Ublox NEO-6, MAX-6, LEA-6 Integration Manual

Abstract

This document describes the features and specifications of the cost effective and high-performance LEA-6, NEO-6 and MAX-6 GPS and GPS/GLONASS/QZSS modules featuring the u-blox 6 positioning engine.

These compact, easy to integrate stand-alone positioning modules combine exceptional performance with highly flexible power, design, and connectivity options. Their compact form factors and SMT pads allow fully automated assembly with standard pick & place and reflow soldering equipment for cost-efficient, highvolume production enabling short time-to-market.

www.u-blox.com

UBX-14054794 - R15

LEA-6 / NEO-6 / MAX-6

u-blox 6 GLONASS, GPS & QZSS modules

Hardware Integration Manual

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Document Information

Title

LEA-6 / NEO-6 / MAX-6

Subtitle

u-blox 6 GLONASS, GPS & QZSS modules

Document type

Hardware Integration Manual

Document number

UBX-14054794

Revision and Date

R15

26-Sep-2017

Document status

Production Information

Document status explanation

Objective Specification

Document contains target values. Revised and supplementary data will be published later.

Advance Information

Document contains data based on early testing. Revised and supplementary data will be published later.

Early Production Information

Document contains data from product verification. Revised and supplementary data may be published later.

Production Information

Document contains the final product specification.

European Union regulatory compliance

Name

Type number

ROM/FLASH version

LEA-6H

All LEA-6H-0-002

FW6.02, FW 7.01, FW 7.03 FW1.00

LEA-6N

All

FW1.00

LEA-6S

All

ROM6.02, ROM7.03

LEA-6A

All

ROM6.02, ROM7.03

LEA-6T-0

All

ROM6.02, ROM7.03

LEA-6T-1

All

FW 7.03

LEA-6T-2

All

FW 6.02

LEA-6R

All

FW DR 1.0, FW 7.03 DR2.0, FW 7.03 DR2.02

NEO-6G

All

ROM6.02, ROM7.03

NEO-6Q

All

ROM6.02, ROM7.03

NEO-6M

All

ROM6.02, ROM7.03

NEO-6P

All

ROM6.02

NEO-6T

All

ROM7.03

NEO-6V

All

ROM7.03

MAX-6G

All

ROM7.03

MAX-6Q

All

ROM7.03

LEA-NEO-MAX-6 complies with all relevant requirements for RED 2014/53/EU. The LEA-NEO-MAX-6 Declaration of Conformity (DoC) is available at www.u-blox.com within Support > Product resources > Conformity Declaration.

This document applies to the following products:

u-blox reserves all rights to this document and the information contained herein. Products, names, logos and designs described herein may in whole or in part be subject to intellectual property rights. Reproduction, use, modification or disclosure to third parties of this document or any part thereof without the express permission of u-blox is strictly prohibited. The information contained herein is provided “as is” and u-blox assumes no liability for the use of the information. No warranty, either express or implied, is given, including but not limited, with respect to the accuracy, correctness, reliability and fitness for a particular purpose of the information. This document may be revised by u-blox at any time. For most recent documents, visit www.u-blox.com.

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Preface

u-blox Technical Documentation

As part of our commitment to customer support, u-blox maintains an extensive volume of technical documentation for our products. In addition to our product-specific technical data sheets, the following manuals are available to assist u-blox customers in product design and development.

 GPS Compendium: This document, also known as the GPS book, provides a wealth of information

regarding generic questions about GPS system functionalities and technology.

 Receiver Description and Protocol Specification: Messages, configuration and functionalities of the u-

blox M8 software releases and receivers are explained in this document.

 Hardware Integration Manual: This Manual provides hardware design instructions and information on

how to set up production and final product tests.

 Application Note: Provides general design instructions and information that applies to all u-blox GNSS

receivers. See section Related documents for a list of Application Notes related to your GNSS receiver.

How to use this manual

This manual has a modular structure. It is not necessary to read it from the beginning to the end. The following symbols are used to highlight important information within the manual:

An index finger points out key information pertaining to chipset integration and performance.

A warning symbol indicates actions that could negatively impact or damage the receiver.

Questions

If you have any questions about u-blox M8 Hardware Integration:

 Read this manual carefully.  Contact our information service on the homepage www.u-blox.com.  Read the questions and answers on our FAQ database on the homepage.

Technical support

Worldwide web

Our website (www.u-blox.com) is a rich pool of information. Product information, technical documents and helpful FAQ can be accessed 24h a day.

By E-mail

If you have technical problems or cannot find the required information in the provided documents, contact the nearest Technical Support office. Use the email addresses in the contact details at the end of this document rather than a personal email address of our staff. This ensures that your request is processed as soon as possible.

Helpful information when contacting technical support

When contacting Technical Support, have the following information ready:

 Receiver type (e.g. LEA-6A-0-000), Datacode (e.g. 160200.0300.000) and firmware version (e.g. FW6.02)  Receiver configuration  Clear description of your question or the problem together with a u-center logfile  A short description of the application  Your complete contact details

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Contents

Preface ................................................................................................................................ 3

Contents .............................................................................................................................. 4

1 Hardware description .................................................................................................. 7

1.1 Overview .............................................................................................................................................. 7

1.2 Architecture .......................................................................................................................................... 7

1.3 Power management ............................................................................................................................. 8

1.3.1 Connecting power ........................................................................................................................ 8

1.3.2 Operating modes .......................................................................................................................... 9

1.4 Antenna supply - V_ANT (LEA-6) .......................................................................................................... 9

1.5 System functions ................................................................................................................................ 10

1.5.1 System monitoring ...................................................................................................................... 10

1.6 Interfaces ............................................................................................................................................ 10

1.6.1 UART ........................................................................................................................................... 10

1.6.2 USB (LEA-6/NEO-6) ...................................................................................................................... 10

1.6.3 Display Data Channel (DDC) ........................................................................................................ 11

1.6.4 SPI (NEO-6, LEA-6R) ..................................................................................................................... 13

1.7 I/O pins ............................................................................................................................................... 16

1.7.1 RESET_N ...................................................................................................................................... 16

1.7.2 EXTINT - External interrupt pin ..................................................................................................... 16

1.7.3 AADET_N (LEA-6) ........................................................................................................................ 16

1.7.4 Configuration pins (LEA-6S/6A, NEO-6) ....................................................................................... 16

1.7.5 Second time pulse for LEA-6T-0 and LEA-6T-1 ............................................................................. 16

1.7.6 TX ready signal (FW 7.0x) ............................................................................................................ 17

1.7.7 ANTOFF (NEO-6) .......................................................................................................................... 17

1.7.8 Antenna supervision signals for LEA-6T-0 .................................................................................... 17

1.7.9 LEA-6R considerations ................................................................................................................. 18

2 Design-in ..................................................................................................................... 19

2.1 Checklist ............................................................................................................................................. 19

2.1.1 Design-in checklist ....................................................................................................................... 19

2.1.2 Design considerations .................................................................................................................. 21

2.1.3 Automotive Dead Reckoning (ADR) solutions .............................................................................. 22

2.2 LEA-6 design ...................................................................................................................................... 23

2.2.1 LEA-6 passive antenna design ...................................................................................................... 23

2.2.2 GLONASS HW design recommendations (LEA-6N, LEA-6H-0-002) ............................................... 25

2.2.3 LEA-6R design ............................................................................................................................. 28

2.2.1 Pin description for LEA-6 designs ................................................................................................. 32

2.3 NEO-6 design ..................................................................................................................................... 33

2.3.1 Passive antenna design (NEO-6) ................................................................................................... 33

2.3.2 Pin description for NEO-6 designs ................................................................................................ 35

2.4 MAX-6 design .................................................................................................................................... 36

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2.4.1 MAX-6 passive antenna design.................................................................................................... 36

2.4.2 Pin description for MAX-6 designs ............................................................................................... 37

2.5 Layout ................................................................................................................................................ 37

2.5.1 Footprint and paste mask ............................................................................................................ 37

2.5.2 Placement ................................................................................................................................... 39

2.5.3 Antenna connection and grounding plane design ....................................................................... 40

2.5.4 Antenna micro strip ..................................................................................................................... 41

2.6 Antenna and antenna supervisor ........................................................................................................ 42

2.6.1 Passive antenna ........................................................................................................................... 43

2.6.2 Active antenna (LEA-6) ................................................................................................................ 43

2.6.3 Active antenna bias power (LEA-6) .............................................................................................. 44

2.6.4 Active antenna supervisor (LEA-6)................................................................................................ 45

2.6.5 Active antenna (NEO-6 and MAX-6) ............................................................................................ 48

2.6.6 External active antenna supervisor using ANTOFF (NEO-6) ........................................................... 50

2.6.7 External active antenna supervisor using ANTON (MAX-6) ........................................................... 51

2.6.8 External active antenna control (NEO-6) ...................................................................................... 52

2.6.9 External active antenna control (MAX-6) ..................................................................................... 53

2.6.10 GPS antenna placement for LEA-6R ............................................................................................. 53

3 Product handling ........................................................................................................ 54

3.1 Packaging, shipping, storage and moisture preconditioning ............................................................... 54

3.1.1 Population of Modules ................................................................................................................ 54

3.2 Soldering ............................................................................................................................................ 54

3.2.1 Soldering paste............................................................................................................................ 54

3.2.2 Reflow soldering ......................................................................................................................... 54

3.2.3 Optical inspection ........................................................................................................................ 55

3.2.4 Cleaning ...................................................................................................................................... 56

3.2.5 Repeated reflow soldering ........................................................................................................... 56

3.2.6 Wave soldering............................................................................................................................ 56

3.2.7 Hand soldering ............................................................................................................................ 56

3.2.8 Rework ........................................................................................................................................ 56

3.2.9 Conformal coating ...................................................................................................................... 57

3.2.10 Casting ........................................................................................................................................ 57

3.2.11 Grounding metal covers .............................................................................................................. 57

3.2.12 Use of ultrasonic processes .......................................................................................................... 57

3.3 EOS/ESD/EMI Precautions .................................................................................................................... 57

3.3.1 Abbreviations .............................................................................................................................. 57

3.3.2 Electrostatic discharge (ESD) ........................................................................................................ 57

3.3.3 ESD handling precautions ............................................................................................................ 58

3.3.4 ESD protection measures ............................................................................................................. 59

3.3.5 Electrical Overstress (EOS) ............................................................................................................ 59

3.3.6 EOS protection measures ............................................................................................................. 59

3.3.7 Electromagnetic interference (EMI) .............................................................................................. 60

3.3.8 Applications with wireless modules LEON / LISA .......................................................................... 61

3.3.9 Recommended parts ................................................................................................................... 63

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3.4 Safety precautions .............................................................................................................................. 64

4 Product testing ........................................................................................................... 65

4.1 u-blox in-series production test ........................................................................................................... 65

4.2 Test parameters for OEM manufacturer .............................................................................................. 65

4.3 System sensitivity test ......................................................................................................................... 66

4.3.1 Guidelines for sensitivity tests ...................................................................................................... 66

4.3.2 ‘Go/No go’ tests for integrated devices ........................................................................................ 66

4.3.3 Testing LEA-6R designs ................................................................................................................ 66

4.3.4 Testing NEO-6V designs .............................................................................................................. 67

Appendix .......................................................................................................................... 68

A Abbreviations ............................................................................................................. 68

B Migration to u-blox-6 receivers ................................................................................. 68

B.1 Checklist for migration ....................................................................................................................... 68

B.2 Software migration ............................................................................................................................. 70

B.2.1 Software migration from ANTARIS 4 or u-blox 5 to a u-blox 6 GPS receiver ................................. 70

B.2.2 Software migration from 6.02 to 7.03 ......................................................................................... 71

B.2.3 Software migration from 7.03 to FW1.00 GLONASS, GPS & QZSS ............................................... 71

B.3 Hardware Migration ........................................................................................................................... 71

B.3.1 Hardware Migration: ANTARIS 4  u-blox 6 ............................................................................... 71

B.3.2 Hardware Migration: u-blox 5  u-blox 6 ................................................................................... 71

B.4 Migration of LEA modules .................................................................................................................. 72

B.4.1 Migration from LEA-4 to LEA-6 ................................................................................................... 72

B.4.2 Migration of LEA-4R designs to LEA-6R ....................................................................................... 73

B.4.3 Migration from LEA-5 to LEA-6 ................................................................................................... 74

B.5 Migration of NEO modules ................................................................................................................. 74

B.5.1 Migration from NEO-4S to NEO-6................................................................................................ 74

B.5.2 Migration from NEO-5 to NEO-6 ................................................................................................. 75

C Interface Backgrounder ............................................................................................. 76

C.1 DDC Interface ..................................................................................................................................... 76

C.1.1 Addresses, roles and modes ........................................................................................................ 76

C.1.2 DDC troubleshooting .................................................................................................................. 77

C.2 SPI Interface ........................................................................................................................................ 78

C.2.1 SPI basics ..................................................................................................................................... 78

D DR calibration ............................................................................................................. 81

D.1 Constraints ......................................................................................................................................... 81

D.2 Initial calibration drive ......................................................................................................................... 81

Related documents........................................................................................................... 83

Revision history ................................................................................................................ 84

Contact .............................................................................................................................. 85

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

RF Front-End

with

Integrated LNA

Baseband Processor

Power

Management

TCXO or

Crystal

RTC

Cry stal

(opti onal )

FLASH EPROM

(optional)

Antenna

Supervision

& Supply

(optional)

Power Control

RF_IN

V_ANT

AADET_N

VCC_RF

VCC

V_BACKUP

G ND

VCC_OUT

UART

EXTINT

RESET_N

USB V2.0

CFG

Digital

IF Filter

Backup

RAM

ROM Code

GPS/GALILEO

Engine

ARM7TDMI-S

SRAM

TIMEPULSE

SAW Filter

RTC

DDC

SPI (optional)

VCC_IO

ANTON

1 Hardware description

1.1 Overview

The u-blox 6 leadless chip carrier (LCC) modules are standalone GPS and GPS/GLONASS/QZSS1 modules featuring the high performance u-blox-6 positioning engine. These compact, easy to integrate modules combine exceptional GPS performance with highly flexible power, design, and connectivity options. Their compact form factors and SMT pads allow fully automated assembly with standard pick & place and reflow-soldering equipment for cost-efficient, high-volume production enabling short time-to-market.

u-blox positioning modules are not designed for life saving or supporting devices or for aviation and should not be used in products that could in any way negatively impact the security or health of the user or third parties or that could cause damage to goods.

1.2 Architecture

u-blox 6 LCC modules consist of two functional parts - the RF and the Baseband sections. See Figure 1 for block diagrams of the modules.

The RF Front-End includes the input matching elements, the SAW bandpass filter, the u-blox 6 RF-IC (with integrated LNA) and the frequency source.

The Baseband section contains the u-blox 6 Baseband processor, the RTC crystal and additional elements such as the optional FLASH Memory for enhanced programmability and flexibility.

Figure 1: u-blox-6 block diagram

GLONASS and QZSS functionality available with LEA-6N, or LEA-6H-0-002 with firmware upgrade.

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VCC

V_BCKP

Voltage

Supervisor

Module Voltage Supply

RTC and Battery Backup RAM (BBR)

1.3 Power management

1.3.1 Connecting power

u-blox 6 receiver modules have three power supply pins: VCC, V_BCKP and VDDUSB.

(No VDDUSB for MAX-6)

1.3.1.1 VCC - main power

The main power supply is fed through the VCC pin. During operation, the current drawn by the u-blox 6 GPS module can vary by some orders of magnitude, especially, if low-power operation modes are enabled. It is important that the system power supply circuitry is able to support the peak power (see data sheet for specification) for a short time. In order to define a battery capacity for specific applications the sustained power figure shall be used.

When switching from backup mode to normal operation or at start-up u-blox 6 modules must charge the

internal capacitors in the core domain. In certain situations this can result in a significant current draw. For low power applications using Power Save and backup modes it is important that the power supply or low ESR capacitors at the module input can deliver this current/charge.

1.3.1.2 V_BCKP - backup battery

In case of a power failure on pin VCC, the real-time clock and backup RAM are supplied through pin V_BCKP. This enables the u-blox 6 receiver to recover from a power failure with either a Hotstart or a Warmstart (depending on the duration of VCC outage) and to maintain the configuration settings saved in the backup RAM. If no backup battery is connected, the receiver performs a Coldstart at power up.

If no backup battery is available connect the V_BCKP pin to GND.

As long as VCC is supplied to the u-blox 6 receiver, the backup battery is disconnected from the RTC and the backup RAM in order to avoid unnecessary battery drain (see Figure 2). Power to RTC and BBR is supplied from

VCC in this case.

Avoid high resistance on the on the V_BCKP line: During the switch from main supply to backup

supply a short current adjustment peak can cause high voltage drop on the pin and possible malfunctions.

Figure 2: Backup Battery and Voltage

1.3.1.3 VDD_USB - USB interface power supply

On LEA-6 and NEO-6 VDD_USB supplies the USB interface. If the USB interface is not used, the VDD_USB pin

must be connected to GND. For more information regarding the correct handling of VDD_USB, see section

1.6.2.1.

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1.3.2 Operating modes

u-blox 6 modules with FW 7.0x or ROM6.02 have two continuous operating modes (Maximum Performance and Eco) and one intermittent operating mode (Power Save mode). Maximum Performance mode freely uses the acquisition engine, resulting in the best possible TTFF, while Eco mode optimizes the use of the acquisition engine to deliver lower current consumption. At medium to strong signals, there is almost no difference for acquisition and tracking performance in these modes.

1.3.2.1 Maximum Performance mode

In Maximum Performance mode, u-blox 6 receivers use the acquisition engine at full performance to search for all possible satellites until the Almanac is completely downloaded.

As a consequence, tracking current consumption level will be achieved when:

 A valid GPS position is fixed  Almanac is entirely downloaded  Ephemeris for all satellites in view are valid

1.3.2.2 Eco mode

In Eco mode, u-blox 6 receivers use the acquisition engine to search for new satellites only when needed for navigation:

 In cold starts, u-blox 6 searches for enough satellites to navigate and optimizes use of the acquisition

engine to download their ephemeris.

 In non-cold starts, u-blox 6 focuses on searching for visible satellites whose orbits are known from the

Almanac.

In Eco mode, the u-blox 6 acquisition engine limits use of its searching resources to minimize power consumption. As a consequence the time to find some satellites at weakest signal level might be slightly increased in comparison to the Maximum Performance mode.

u-blox 6 deactivates the acquisition engine as soon as a position is fixed and a sufficient number (at least 4) of satellites are being tracked. The tracking engine continues to search and track new satellites without orbit information.

1.3.2.3 Power Save mode

u-blox 6 receivers include a Power Save Mode. Its operation is called cyclic tracking and allows reducing the average power consumption significantly. The Power Save Mode can be configured for different update periods. u-blox recommends an update period of 1s for best GPS performance. For more information, see the u-blox 6 Receiver Description including Protocol Specification [4]

Dead Reckoning, PPP and Precision Timing features should not be used together with Power Save Mode. Power Save Mode is not supported in GLONASS mode.

1.4 Antenna supply - V_ANT (LEA-6)

LEA-6 modules support active antenna supply and supervision use the pin V_ANT to supply the active antenna. Use a 10  resistor in front of V_ANT. For more information about antenna and antenna supervisor, see section

2.6.

If not used, connect the V_ANT pin to GND.

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Module

VDD_USB

LDO

VDD_USB

USB_DP

USB_DM

C24 C23

VBUS

GND

USB Device Connector

EN R11

1.5 System functions

1.5.1 System monitoring

The u-blox-6 receiver modules provide system monitoring functions that allow the operation of the embedded processor and associated peripherals to be supervised. These System Monitoring functions are output as part of the UBX protocol, class ‘MON’.

Please refer to the u-blox 6 Receiver Description including Protocol Specification [4]. For more information on UBX messages, serial interfaces for design analysis and individual system monitoring functions.

1.6 Interfaces

1.6.1 UART

u-blox 6 modules include a Universal Asynchronous Receiver Transmitter (UART) serial interface. RxD1/TxD1 supports data rates from 4.8 to 115.2 kBit/s. The signal output and input levels are 0 V to VCC. An interface based on RS232 standard levels (+/- 12 V) can be realized using level shifters such as Maxim MAX3232. Hardware handshake signals and synchronous operation are not supported.

For more information, see the LEA-6 Data Sheet [1], NEO-6 Data Sheet [3],or MAX-6 Data Sheet [11].

1.6.2 USB (LEA-6/NEO-6)

The u-blox 6 Universal Serial Bus (USB) interface supports the full-speed data rate of 12 Mbit/s.

1.6.2.1 USB external components

The USB interface requires some external components in order to implement the physical characteristics required by the USB 2.0 specification. These external components are shown in Figure 3 and listed in Table 1.

In order to comply with USB specifications, VBUS must be connected through a LDO (U1) to pin VDD_USB of the module.

If the USB device is self-powered it is possible that the power supply (VCC) is shut down and the Baseband-IC core is not powered. Since VBUS is still available, it still would be signaled to the USB host that the device is present and ready to communicate. This is not desired and thus the LDO (U1) should be disabled using the enable signal (EN) of the VCC-LDO or the output of a voltage supervisor. Depending on the characteristics of the LDO (U1) it is recommended to add a pull-down resistor (R11) at its output to ensure VDD_USB is not floating if LDO (U1) is disabled or the USB cable is not connected i.e. VBUS is not supplied.

If the device is bus-powered, LDO (U1) does not need an enable control.

Figure 3: USB Interface

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Name

Component

Function

Comments

LDO

Regulates VBUS (4.4 …5.25 V)

down to a voltage of 3.3 V.

Almost no current requirement (~1 mA) if the GPS receiver is operated as a USB self-powered device, but if bus-powered LDO (U1) must be able to deliver the maximum current of ~70 mA. A low-cost DC/DC converter such as LTC3410 from Linear Technology may be used as an alternative.

C23, C24

Capacitors

Required according to the specification of LDO U1

Protection diodes

Protect circuit from overvoltage / ESD when connecting.

Use low capacitance ESD protection such as ST Microelectronics USBLC6-2.

R4, R5

Serial termination resistors

Establish a full-speed driver impedance of 28…44 

A value of 22  is recommended. R11

Resistor

10 k is recommended for USB self-powered setup. For bus-powered setup R11 can be ignored.

Load Capacitance

Pull-Up Resistor Value R20, R21

50 pF

N/A

100 pF

18 k

250 pF

4.7 k

Table 1: Summary of USB external components

1.6.3 Display Data Channel (DDC)

An I2C compatible Display Data Channel (DDC) interface is available with LEA-6, NEO-6 and MAX-6 modules for serial communication. For more information about DDC implementation refer to the u-blox 6 Receiver Description including Protocol Specification [4]. Background information about the DDC interface is available in Appendix C.1.

u-blox 6 GPS receivers normally run in I2C slave mode. Master Mode is only supported when external

EEPROM is used to store configuration. No other nodes may be connected to the bus. In this case, the receiver attempts to establish presence of such a non-volatile memory component by writing and reading from a specific location.

TX ready indicator (data ready) for FW 7.0x. See section 1.7.6.

The u-blox 6 DDC interface supports serial communication with u-blox wireless modules. See the

specification of the applicable wireless module to confirm compatibility.

With u-blox 6, when reading the DDC internal register at address 0xFF (messages transmit buffer), the

master must not set the reading address before every byte accessed as this could cause a faulty behavior. Since after every byte being read from register 0xFF the internal address counter is incremented by one saturating at 0xFF, subsequent reads can be performed continuously.

Pins SDA2 and SCL2 have internal 13 k pull-ups. If capacitive bus load is very large, additional external pull-ups may be needed in order to reduce the pull-up resistance.

Table 2 lists the maximum total pull-up resistor values for the DDC interface. For small loads, e.g. if just connecting to an external EEPROM, these built-in pull-ups are sufficient.

Table 2: Pull-up resistor values for DDC interface

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1.6.3.1 Communicating to an I

C EEPROM with the GPS receiver as I2C master

Serial I2C memory can be connected to the DDC interface. This can be used to save configuration permanently. It will automatically be recognized by firmware. The memory address must be set to 0b10100000 (0xA0) and the size fixed to 4 kB.

Figure 4: Connecting external serial I2C memory used by the GPS receiver (see EEPROM data sheet for exact pin orientation)

Figure 5: Connecting external serial I2C memory used by external host (see data sheet for exact pin orientation)

Note that the case shown on Figure 4 is different than the case when EEPROM is present but used by external host / CPU as indicated on Figure 5. This is allowed but precaution is required to ensure that the GPS receiver does not detect the EEPROM device, which would effectively configure the GPS receiver to be MASTER on the bus causing collision with the external host.

To ensure that the EEPROM device (connected to the bus and used by the host) is not detected by the GPS receiver it is important to set the EEPROM’s address to a value different than 0xA0. This way EEPROM remains free to be used for other purposes and the GPS receiver will assume the SLAVE mode.

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Manufacturer

Order No.

M24C32-R

Microchip

24AA32A

Catalyst

CAT24C32

Samsung

S524AB0X91

u-blox GPS Receiver SPI Master

SS_N

MISO

SCS_N

VDD

MOMOSI

SCK SCK

VDD

At start up ensure that the host allows enough time (250 ms) for the receiver to interrogate any external

EEPROM over the bus. The receiver always performs this interrogation within 250 ms of start up, and the external host must provide the GPS receiver sufficient time to complete it. Only after the interrogation can the host enter MASTER mode and have full control over the bus.

Following I2C serial EEPROM are supported:

Table 3: Recommend parts list for I2C Serial EEPROM memory

1.6.4 SPI (NEO-6, LEA-6R)

A Serial Peripheral Interface (SPI) is available with u-blox 6 NEO modules. The SPI allows for the connection of external devices with a serial interface, e.g. FLASH memories or A/D converters, or to interface to a host CPU.

LEA-6R includes a Serial Peripheral Interface (SPI) for connecting external sensors. The interface can be operated in SPI master mode only. Two chip select signals are available to select external slaves. See section 2.2.3.1.

TX ready indicator (data ready) for LEA-6H (FW 7.0x). See section 1.7.6.

Background information about the SPI interface is available in Appendix C.2.

1.6.4.1 Connecting SPI FLASH memory (NEO-6 modules)

SPI FLASH memory can be connected to the SPI interface to save Assist Now Offline data and/or receiver configuration. It will automatically be recognized by firmware when connected to SS_N.

Figure 6 shows how external memory can be connected. Minimum SPI FLASH memory size is 1 Mbit.

Figure 6: Connecting external SPI Memory to u-blox GPS receivers

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Manufacturer

Order No.

Winbond

W25X10A

Winbond

W25X20A

AMIC

A25L010

AMIC

A25L020

Table 4: Supported SPI FLASH memory devices

u-blox GPS Receiver SPI Master

SS_N

MISO

SCS_N

VDD

MOMOSI

SCK SCK

VDD

Following SPI serial Flash are supported:

Only use serial FLASH types listed in Table 4. For new designs confirm if the listed type is still available. It is

not possible to use other serial FLASH types than those listed in Table 4 with u-blox 6 receivers.

1.6.4.2 SPI communication (connecting to an SPI master) NEO-6

Figure 7 shows how to connect a u-blox GPS receiver to a host/master. The signal on the pins must meet the conditions specified in the Data Sheet.

Figure 7: Connecting to SPI Master

For those u-blox 6 modules supporting SPI the SPI MOSI, MISO and SCK pins share a configuration

function at start up. To secure correct receiver operation make sure that the SS_N pin is high at start up. Afterwards the SPI function will not affect the configuration pins.

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Component

Description

Model

Supplier

U1 – U3

Buffer

NC7SZ125

Fairchild

1.6.4.3 Pin configuration with module as one of several slaves

The buffers enabled by the CS_N signal make sure that the GPS receiver starts up with a known defined configuration, since the SPI pins (MOSI, MISO and SCK) are at start up also configuration pins.

Figure 8: Diagram of SPI Pin Configuration

Table 5: Recommended components for SPI pin configuration

Use same power voltage to supply U1 – U3 and VCC.

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1.7 I/O pins

1.7.1 RESET_N

LEA-6 modules include a RESET_N pin. Driving RESET_N low activates a hardware reset of the system. RESET_N is only an input and will not reset external circuitry.

Use components with open drain output (i.e. with buffer or voltage supervisor). There is an internal pull up resistor of 3.3 k to VCC inside the module that requires that the reset circuitry can

deliver enough current (e.g. 1 mA). Do not drive RESET_N high. NEO-6 and MAX-6 modules do not include a RESET_N pin. However, this functionality can be implemented for

these modules by connecting the NEO-6 and MAX-6 pin 8 to pin 9 with a 3.3 k resistor, instead of connecting them directly. Pin 8 (NEO-6) or pin 9 (MAX-6) can then be used as a RESET_N input with the same characteristics as the reset pin on LEA-6 modules.

Use caution when implementing RESET_N on NEO-6 and MAX-6 modules since forward

compatibility is not guaranteed.

1.7.2 EXTINT - External interrupt pin

EXTINT0 is an external interrupt pin with fixed input voltage thresholds with respect to VCC (see the data sheet

for more information). It can be used for the time mark function on LEA-6T or for wake-up functions in Power Save Mode on all u-blox 6 LCC modules. Leave open if unused.

1.7.3 AADET_N (LEA-6)

AADET_N is an input pin and is used to report whether an external circuit has detected an external antenna or

not. Low means the antenna has been detected. High means no external antenna has been detected. See section 2.6.4 for an implementation example.

1.7.4 Configuration pins (LEA-6S/6A, NEO-6)

ROM-based modules provide up to 3 pins (CFG_COM0, CFG_COM1, and CFG_GPS0) for boot-time configuration. These become effective immediately after start-up. Once the module has started, the configuration settings can be modified with UBX configuration messages. The modified settings remain effective until power-down or reset. If these settings have been stored in battery-backup RAM, then the modified configuration will be retained, as long as the backup battery supply is not interrupted.

The module data sheets indicate the meaning of the configuration pins when they are high (1) or low (0). In fact no configuration pins need to be pulled high. All have internal pull ups and therefore default to the high (1) state when left open or connected to a high impedance output. They should be left open unless there is a need to pull them low to alter the initial configuration.

Some configuration pins are shared with other functions. During start-up, the module reads the state of the configuration pins. Afterwards the other functions can be used.

The configuration pins of u-blox 6 use an internal pull-up resistor, which determines the default setting.

For more information about settings and messages see the module data sheet.

MAX-6 doesn’t have pins for boot-time configuration.

1.7.5 Second time pulse for LEA-6T-0 and LEA-6T-1

LEA-6T-0 and LEA-6T-1 include a second time pulse pin (TIMEPULSE2). For more information and configuration see the LEA-6 Data Sheet [1] and also the u-blox 6 Receiver Description including Protocol Specification [4]. (LEA6T-2 provides a single time pulse output only.)

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1.7.6 TX ready signal (FW 7.0x)

The TX ready signal indicates that the receiver has data to transmit. A listener can wait on the TX ready signal instead of polling the DDC or SPI interfaces. The UBX-CFG-PRT message lets you configure the polarity and the number of bytes in the buffer before the TX ready signal goes active. The TX ready signal can be mapped to GPIO 05 (TXD1). The TX ready pin is disabled by default.

The TX-ready functionality can be enabled and configured by proper AT commands sent to the involved

u-blox wireless module supporting the feature. For more information see GPS Implementation Application Note, Docu No GSM.G1-CS-09007 [14]

1.7.7 ANTOFF (NEO-6)

The ANTOFF signal can be mapped to GPIO22 (Pin 17). The ANTOFF signal is disabled by default.

To configure the ANTOFF function refer to the u-blox 6 Receiver Description including Protocol

Specification [3].

Use caution when implementing ANTOFF configuration since forward compatibility is not

guaranteed

1.7.8 Antenna supervision signals for LEA-6T-0

With LEA-6T-0, the antenna supervisor GPIOs are numbered differently than the other LEA-6 modules and are wired to specific PIOs:

 ANTOFF is internally mapped to GPIO13  ANTSHORT is internally mapped to GPIO17  AADET_N (Active Antenna Detect) is mapped to GPIO8 (Pin 20)

If the unit is reverted to the default configuration, there is no antenna supply. The CFG-ANT command sets the PIOs and enables Power Control, Short Circuit Detection, Power Down on Short

and Short Circuit Recovery. To store the settings permanently send the UBX-CFG-CFG command with the option 'save current parameters'

to BBR AND SPI Flash (!) Also see the schematic of open circuit detection, Figure 46.

To configure this function refer to the u-blox 6 Receiver Description including Protocol Specification [3].

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Signal name

Direction

Usage

SPEED

Input

Odometer Speedpulses

SCK

Output

SPI clock

SPI_SCS1_N

Output

Chip Select signal for ADC/turn rate sensor

FWD

Input

Direction indication (1 = forward)

SPI_SCS2_N

Output

Chip Select signal for temperature sensor

MISO

Input

Serial data (Master In / Slave Out)

MOSI

Output

Serial data (Master Out / Slave In), leave open

1.7.9 LEA-6R considerations

Figure 9: Block schematic of complete LEA-6R design

LEA-6R includes the following special pins: SPI_MOSI, SPI_MISO, SPI_SCS2_N, FWD, SPI_ SCS1_N, SPI_SCK, and SPEED.

Table 6: LEA-6R special pins

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2 Design-in

For migrating existing ANTARIS®4 product designs to u-blox 6 please refer to Appendix B.

In order to obtain good performance with a GPS receiver module, there are a number of points that require careful attention during the design-in. These include:

 Power Supply: Good performance requires a clean and stable power supply.  Interfaces: Ensure correct wiring, rate and message setup on the module and your host system.  Antenna interface: For optimal performance seek short routing, matched impedance and no stubs.

2.1 Checklist

Good performance requires a clean and stable power supply with minimal ripple. Care needs to be exercised in selecting a strategy to achieve this. Series resistance in the Vcc supply line can negatively impact performance. For better performance, use an LDO to provide a clean supply at Vcc and consider the following:

 Wide power lines or even power planes are preferred.  Place LDO near the module.  Avoid resistive components in the power line (e.g. narrow power lines, coils, resistors, etc.).  Placing a filter or other source of resistance at Vcc can create significantly longer acquisition times.

2.1.1 Design-in checklist

Designing-in a u-blox 6 module is easy, especially when based on a u-blox reference design. Nonetheless, it pays to do a quick sanity check of the design. This section lists the most important items for a simple design check. The Design-In Checklist also helps to avoid an unnecessary respin of the PCB and helps to achieve the best possible performance.

Follow the design-in checklist when developing any u-blox 6 GPS applications. This can significantly

reduce development time and costs.

Have you chosen the optimal module?

u-blox 6 modules have been intentionally designed to allow GPS receivers to be optimally tailored to specific applications. Changing between the different variants is easy.

 Do you need TCXO performance – Then choose an H  Do you want to be able to upgrade the firmware? Then you will have to use a programmable receiver

module: choose an H2 variant.

 Do you need USB? All LEA-6 and NEO-6 modules support USB.  Do you need Dead Reckoning – Then choose a LEA-6R or NEO-6V (see section 2.1.3)  Do you need Precise Point Positioning – Then choose a NEO-6P  Do you need Precision Timing – Then choose a LEA-6T or NEO-6T.  Do you need onboard Antenna Supervisor circuitry - Then choose the LEA form factor.  Do you need onboard Antenna control - Then choose the MAX form factor.  Du you need smallest size and forward compatibility- Then choose the MAX form factor.  Do you need low power - Then choose 1.8V 6G module variant.  Do you need GLONASS - Then choose LEA-6N.

, S3, Q4 or G5 variant.

LEA-6H LEA-6S NEO-6Q / MAX-6Q NEO-6G / MAX-6G

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Check Power Supply Requirements and Schematic:

 Is the power supply within the specified range? (See data sheet.)  Is the voltage VDDUSB within the specified range?  Compare the peak current consumption of your u-blox 6 module (~70 mA) with the specification of the

power supply.

 GPS receivers require a stable power supply, avoid ripple on VCC (<50 mVpp)  For low power applications using Power Save and backup modes, ensure that the power supply or low ESR

capacitors at the module input can deliver the required current/charge for switching from backup mode to normal operation. In certain situations charging the internal capacitors in the core domain can result in a significant instantaneous current draw.

Backup Battery

 For achieving a minimal Time To First Fix (TTFF) in Hotstart or a Warmstart, connect a backup battery to

V_BCKP.

 Time information is a requirement for AssistNow Offline, AssistNow Autonomous and when in Power Save

Mode with update period longer than 10 s.

Antenna

 The total noise figure should be well below 3 dB.  If a patch antenna is the preferred antenna, choose a patch of at least 15x15x4 mm. For smaller antennas

an LNA with a noise figure <2 dB is recommended. To optimize TTFF make use of u-blox’ free A-GPS services AssistNow Online and AssistNow Offline.

 Make sure the antenna is not placed close to noisy parts of the circuitry. (e.g. micro-controller, display, etc.)  For active antennas add a 10  resistor in front of V_ANT

input for short circuit protection or use the

antenna supervisor circuitry.

 To optimize performance in environments with out-band jamming sources, use an additional SAW filter.

For information on ESD protection for patch antennas and removable antennas, see section 3.3.4 and if

you use GPS for design in combination with GSM or other radio, then check sections 3.3.6 to 3.3.8.

For more information dealing with interference issues see the GPS Antenna Application Note [5].

Schematic

 If required, does your schematic allow using different module variants?  Don’t drive RESET_N high!  Don’t drive configuration pins high, they already have internal pull-ups.  Plan the use of 2nd interface (Testpoints on UART, DDC or USB) for firmware updates or as a service

connector.

Layout optimizations (Section 2.5)

 Is the GPS module placed according to the recommendation in section 2.5.2?  Has the Grounding concept been followed? (See section 2.5.3.)  Has the micro strip been kept as short as possible?  Add a ground plane underneath the GPS module to reduce interference.  For improved shielding, add as many vias as possible around the micro strip, around the serial

communication lines, underneath the GPS module etc.

 Have appropriate EOS/ESD/EMI protection measures been included? (See section 3.3.) This is especially

important for designs including 2G, 3G modules.

Only available with LEA-6 modules

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Calculation of the micro strip (Section 2.5.4)

 The micro strip must be 50  and be routed in a section of the PCB where minimal interference from noise

sources can be expected.

 In case of a multi-layer PCB, use the thickness of the dielectric between the signal and the 1st GND layer

(typically the 2nd layer) for the micro strip calculation.

 If the distance between the micro strip and the adjacent GND area (on the same layer) does not exceed 5

times the track width of the micro strip, use the “Coplanar Waveguide” model in AppCad to calculate the micro strip and not the “micro strip” model.

2.1.2 Design considerations

For a minimal design with a u-blox 6 GPS module the following functions and pins need to be considered:

 Connect the Power supply to VCC.  VDDUSB: Connect the USB power supply to a LDO before feeding it to VDDUSB and VCC. Or connect to

GND if USB is not used.

 Assure a optimal ground connection to all ground pins of the module  Connect the antenna to RF_IN over a matching 50  micro strip and define the antenna supply (V_ANT)

for active antennas (internal or external power supply)

 Choose the required serial communication interface (UART, USB, SPI or DDC) and connect the appropriate

pins to your application

 If you need Hot- or Warmstart in your application, connect a backup battery to V_BCKP  Decide whether TIMEPULSE or RESET_N7 options are required in your application and connect the

appropriate pins on your module

Only available with LEA-6 modules, but see section 1.7.1 for NEO-6 modules.

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2.1.3 Automotive Dead Reckoning (ADR) solutions

u-blox’ ADR supports different sensor inputs. The classical setup, called “Gyroscope plus Wheel Tick” (GWT), consists of a gyroscope providing the heading information and wheel tick providing the speed information.

Alternatively, sensor information from left and right wheels (front or rear) or all wheels are used differentially to deduce heading, called “Differential Wheel Tick” (DWT). This results in slightly lower performance compared to GWT, but has the big advantage of saving the cost of a gyroscope.

2.1.3.1 Software sensor interface

Figure 10: Software sensor interface

The industry proven u-blox ADR solution is highly flexible. The application processor can support a vast array of sensors, and must only convert the sensor data into UBX messages and pass them to the GPS receiver via a standard serial interface (USB, SPI, UART, DDC). This makes the u-blox ADR solution very portable between various vehicle platforms and reduces development effort and time-to-market. u-blox ADR is completely selfcalibrating, and requires only pre-configuration to the specific vehicle platform.

u-blox’ ADR with software sensor interface is available as NEO-6V module. These components are ideal for factory installed navigation since they use sensor data (wheel tick and gyroscope data) taken directly from the CAN bus.

2.1.3.2 Hardware sensor interface

Figure 11: Hardware sensor interface

The standard quality grade LEA-6R module is a dedicated ADR solution (GWT only) for aftermarket installations with no access to the vehicle bus and no application processor for sensor data processing. Sensors are connected directly to the module: gyroscopes via SPI and ADC and the speed pulse information from the tachometer.

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USB port

Passive Antenna

Vcc

Micro

Processor

(serial)

(optional)

Backup Battery (optional)

Micro

Processor

(USB)

SDA2 /SPI_MOSI

SCL2 / SPI_MISO

TxD1

RxD1

VCC

GND

VCC_OUT

CFG_COM1/ NC

SPI_SCS2_N /TIMEPULSE2

RESET_N

V_BCKP

Reserved

GND

RF_IN

VCC_RF

V_ANT

Reserved / FWD

Reserved / SPI_SCS1_N

Reserved / SPI_SCK

VDDUSB

USB_DM

USB_DP

EXTINT0 / SPEED

TIMEPULSE

GND

AADET_N

LEA-6

Top View

LDO

Passive Antenna

Vcc

Micro

Processor

(serial)

SDA2 / SPI_MOSI

SCL2 / SPI_MISO

TxD1

RxD1

VCC

GND

VCC_OUT

CFG_COM1/ NC

SPI_SCS2_N /TIMEPULSE2

RESET_N

V_BCKP

Reserved

GND

RF_IN

VCC_RF

V_ANT

Reserved / FWD

Reserved / SPI_SCS1_N

Reserved / SPI_SCK

VDDUSB

USB_DM

USB_DP

EXTINT0 / SPEED

TIMEPULSE

GND

AADET_N

LEA-6

Top View

2.2 LEA-6 design

2.2.1 LEA-6 passive antenna design

This is a minimal setup for a PVT GPS receiver with a LEA-6 module.

Figure 12: LEA-6 passive antenna design with USB port

Figure 13: LEA-6 passive antenna design with no USB port or backup battery

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For best performance with passive antenna designs use an external LNA to increase the sensitivity up to 2

dB. See figure 12 and Figure 15.

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Passive Antenna

Vcc

Micro

Processor

(serial)

SDA2 / SPI_MOSI

SCL2 / SPI_MISO

TxD1

RxD1

VCC

GND

VCC_OUT

CFG_COM1/ NC

SPI_SCS2_N /TIMEPULSE2

RESET_N

V_BCKP

Reserved

GND

RF_IN

VCC_RF

V_ANT

Reserved / FWD

Reserved / SPI_SCS1_N

NReserved / SPI_SCK

VDDUSB

USB_DM

USB_DP

EXTINT0 / SPEED

TIMEPULSE

GND

AADET_N

LEA-6

Top View

LNA

SAW L

Passive Antenna

Vcc

Micro

Processor

(serial)

SDA2 / SPI_MOSI

SCL2 / SPI_MISO

TxD1

RxD1

VCC

GND

VCC_OUT

CFG_COM1/ NC

SPI_SCS2_N /TIMEPULSE2

RESET_N

V_BCKP

Reserved

GND

RF_IN

VCC_RF

V_ANT

Reserved / FWD

Reserved / SPI_SCS1_N

Reserved / SPI_SCK

VDDUSB

USB_DM

USB_DP

EXTINT0 / SPEED

TIMEPULSE

GND

AADET_N

LEA-6

Top View

SAW

LNA

SAW

Figure 14: LEA-6 passive antenna design for best performance (with external LNA and SAW)

Figure 15: LEA-6 passive antenna design for best performance and increased immunity to jammers such as GSM

For information on increasing immunity to jammers such as GSM see section 3.3.8.

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2.2.2 GLONASS HW design recommendations (LEA-6N, LEA-6H-0-002

)

The Russian GLONASS satellite system is an alternative system to the US-based Global Positioning System (GPS). LEA-6N modules can receive and process GLONASS signals. LEA-6H-0-002 modules are GLONASS ready and are capable of receiving and processing GLONASS signals via a firmware upgrade8.

LEA-6N and LEA-6H-0-002 designs for GLONASS require a wide RF path. Ensure that the antenna and external SAW filter are sufficient to allow GLONASS & GPS signals to pass (see Figure 16).

Use an active GLONASS antenna. For best performance with passive antenna designs use an external LNA. (See section 2.2.2.7.)

LEA-6N and LEA-6H-0-002 modules are pin compatible.

2.2.2.1 Wide RF path

As seen in Figure 16, the GLONASS / GPS satellite signals are not at the same frequency. For this reason the RF path, LNA, filter, and antenna must be modified accordingly to let both signals pass.

2.2.2.2 Filter

 Use a GPS & GLONASS SAW filter (see Figure 16) that lets both GPS and GLONASS signals pass. (See the

recommended parts list in section 3.3.9.)

 If an active antenna is used, make sure that any filter inside is wide enough.

Figure 16: GPS & GLONASS SAW filter

2.2.2.3 Active antenna

Usually an active GPS antenna includes a GPS band pass filter which might filter out the GLONASS signal (see Figure 16). For this reason make sure that the filter in the active antenna is wide enough to let the GPS and GLONASS signals pass.

In combined GPS & GLONASS antennas, the antenna has to be tuned to receive both signals and the filter has a larger bandwidth to provide optimal GPS & GLONASS signal reception (see Figure 16).

Use a good performance GPS & GLONASS active antenna (for recommended components see section

3.3.9.1).

Figure 17: GPS & GLONASS active antenna

Requires firmware upgrade with FW1.00 GLONASS, GPS & QZSS Flash firmware image, available from u-blox.

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size

Typical bandwidth

36*36*4 mm

40 MHz

25*25*4 mm

20 MHz

18*18*4 mm

10 MHz

15*15*4 mm

8 MHz

12*12*4 mm

7 MHz

10*10*4 mm

5 MHz

2.2.2.4 Passive Antenna

The bandwidth of a ceramic patch antenna narrows with size (see Table 7).

Table 7: Typical bandwidths for GPS patch antennas

Figure 18 shows a 12*12*4 mm patch antenna with 20*20 mm ground plane, tuned to GPS. This patch bandwidth is so narrow that it cannot be simultaneously matched to GPS and GLONASS.

Figure 18: 12*12*4 patch antenna on 20*20 mm GND plane

Figure 19 shows a 25*25*4 mm patch antenna with 60*60 mm ground plane. Due to the larger bandwidth, it can be matched to GPS and GLONASS.

Figure 19: 25*25*4 mm patch antenna on 60*60 mm GND plane

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Figure 20 show a 36*36*4 mm patch antenna. Due to the large bandwidth, the antenna is also tolerant to changes in the ground plane.

Figure 20 36*36*4 mm patch antenna

Use at least a 25*25*4 mm patch antenna, (a 36*36*4 mm patch antenna is better) and tune it so that

GPS & GLONASS signals are received.

2.2.2.5 Module designs

For GPS & GLONASS designs chose the LEA-6N GLONASS, GPS & QZSS module, which has a wide RF path and includes an internal Flash.

2.2.2.6 Module design with active antenna

Figure 21 shows a GPS & GLONASS active antenna design with the LEA-6N GLONASS, GPS & QZSS module.

Figure 21: Module design with active antenna

Use a good performance GPS & GLONASS active antenna (for recommended components, see section

3.3.9.1).

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Signal name

Direction

Usage

SPI_SCK

Output

SPI clock 22

SPI_SCS1_N

Output

Chip Select signal for ADC/turn rate sensor

SPI_SCS2_N

Output

Chip Select signal for temperature sensor

SPI_MISO

Input

Serial data (Master In / Slave Out)

SPI_MOSI

Output

Serial data (Master Out / Slave In), leave open

2.2.2.7 Module design with passive antenna and an external LNA

Figure 22 shows a GPS & GLONASS passive antenna design with the LEA-6N GLONASS, GPS & QZSS module. For best performance with passive antenna designs use an external LNA.

Figure 22: Module design with passive antenna

A standard GPS LNA has enough bandwidth to amplify GPS and GLONASS.

For recommended SAW Filters for GPS & GLONASS (Part F2 in Figure 22), see section 3.3.9.

2.2.2.8 GLONASS SW integration

To activate GLONASS mode the customer application will have to send UBX proprietary commands for activating and switching to GLONASS reception. The applicable SW commands are documented in the u-blox 6 Receiver Description including Protocol Specification (GPS/GLONASS/QZSS) [5].

2.2.3 LEA-6R design

2.2.3.1 Connecting gyroscope and temperature sensor to the LEA-6R

The LEA-6R acts as SPI master. Following signals are used by the SPI:

Table 8: SPI pins for LEA-6R

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LEA-6R

Turn Rate Sensor

(MOSI)

22K

10R

leave open

Gyro

SCK

MISO

SPI_SCS2_N

+5V

REF

100nF

GND

CONV

SCK

VCC

REF

12-Bit

A/D Converter

Linear LTC1860

Temperature

Sensor

National LM70-5

SDO

SI/O

GND

100nF

RATE

100nF

GND

100K

SPI_SCS1_N

10uF

220nF

+5V

+3V

+5V

+3V

Parameter

Specification

Supply Voltage

5.0 V ± 0.25 V

Zero Point

2.5 V ± 0.4 V

Scale Factor

25 mV/(°/s) ± 5 mV/(°/s)

Dynamic Range

±60 °/s to ±125 °/s

Linearity

±0.5 % (full scale)

Recommended operating temperature range

-40 to +85°C

The following block schematic specifies the A/D converter and temperature sensor for the LEA-6R.

The LTC1860 and LM70-5 function at 5 V. A level translation with open-drain buffers and pull-up

resistors on the outputs is required.

Figure 23: Attaching A/D converter and temperature sensor using the SPI

Add appropriate coupling capacitances according to the recommendations in the data sheets of the illustrated semiconductor products. All shown resistors shall have 5% accuracy or better. All shown capacitors (X7R types) shall have 10% accuracy or better.

For correct operation with the LEA-6R firmware, this circuit must be adopted without making any modifications such as, but not limited to, using different types of semiconductor devices and changing signal assignment.

LEA-6R default SPI clock is 870 kHz. As LEA-4R default value is 460 kHz, migrating from LEA-4R to LEA-6R

will require a bandwidth verification of the SPI circuits and shall be designed for a bandwidth of 4 MHz.

2.2.3.2 Gyroscope requirements

Gyroscopes should meet the requirements listed below:

Table 9: Requirements for gyroscopes

Follow the gyroscope manufacturer design recommendations for proper analog signal conditioning.

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Manufacturer

Device

Linear Technology

LTC1860

Manufacturer

Device

National Semiconductor

LM70

Signal name

Direction

Usage

FWD

Input

Direction indication (1 = forward)

2.2.3.3 Supported A/D converters

The following table lists the supported A/D converters:

Table 10: Supported A/D converters

2.2.3.4 Supported temperature sensors

The following table lists the supported temperature sensors:

Table 11: Supported temperature sensors

Note, that the temperature sensor inside the EPSON XV-8000 gyroscope sensor is not supported.

2.2.3.5 Forward / Backward indication

Use of the forward / backward indication signal FWD is optional but strongly recommended for good dead reckoning performance. It has an internal pull-up and therefore can be left open or connected to VCC_OUT or VCC if not used.

You need to check the voltage levels and the quality of the vehicle signals. They may be of different voltage levels, for example 12V nominal with a certain degree of variation. Use of optocouplers or other approved EMI protection and filtering is strongly recommended.

If no direction signal is available, the direction must be set to forward by configuring the meaning of the

direction pin appropriately, otherwise DR positioning will be incorrect due to the wrong direction. GPS only navigation is not affected by this configuration.

As the forward/backward direction signal is not available in all cars, try to make use of the reverse gear

light.

Table 12: LEA-6R Forward / Backward indication

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Signal name

Direction

Usage

SPEED

Input

Odometer Speedpulses

2.2.3.6 Odometer / Speedpulses

DR receivers use signals from sensors in the car to establish the velocity and distance traveled. These sensors are referred to as the odometer and the signals can be designated odometer pulses, speedpulses, speed ticks, wheel pulses or wheel ticks. These terms are often used interchangeably which can sometimes lead to confusion. For the sake of consistency, in this document we will be referring to these signals as speedpulses.

Table 13: LEA-6R Odometer / Speedpulses

The speedpulse signal required for DR modules must have a frequency range from 1 Hz to 2 kHz (0 Hz is equal to a speed of 0 km/hour) and must be linear to the driven speed.

For DR calibration see section D.

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Function

I/O

Description

Remarks

Power

VCC 6 I

Supply Voltage

Provide clean and stable supply.

GND

7, 13-15, 17

Ground

Assure a good GND connection to all GND pins of the module, preferably with a large ground.

VCC_OUT

8 O

Leave open if not used.

V_BCKP

11 I Backup voltage supply

It’s recommended to connect a backup battery to V_BCKP in order to enable Warm and Hot Start features on the receivers. Otherwise connect to GND.

VDDUSB

24 I USB Power Supply

To use the USB interface connect this pin to 3.0 – 3.6V derived from VBUS. If no USB serial port used connect to GND.

Antenna

RF_IN

16 I GPS/GALILEO signal input from antenna

Use a controlled impedance transmission line of 50 Ohm to connect to RF_IN.

Don’t supply DC through this pin. Use V_ANT pin to supply power.

VCC_RF

18 O Output Voltage RF section

Can be used to power an external active antenna (VCC_RF connected to V_ANT with 10 ). The max power consumption of the Antenna must not exceed the datasheet specification of the module. Leave open if not used.

V_ANT

19 I Antenna Bias voltage

Connect to GND (or leave open) if Passive Antenna is used. If an active Antenna is used, add a 10  resistor in front of V_ANT input to the Antenna Bias Voltage or VCC_RF

AADET_N

20 I Active Antenna Detect

Input pin for optional antenna supervisor circuitry. Leave open if not used.

UART

TxD1

3 O Serial Port 1

Communication interface can be programmed as TX ready for I2C interface. Leave open if not used.

RxD1

4 I Serial Port 1

Serial port input with internal pull-up resistor to VCC. Leave open if not used. Don’t use external pull up resistor.

USB USB_DM

I/O

USB I/O line

USB2.0 bidirectional communication pin. Leave open if unused. Implementations see section 1.6.2.

USB_DP

I/O

USB I/O line

System

RESET_N

10 I Hardware Reset (Active Low)

Leave open if not used. Do not drive high.

TIMEPULSE

28 O Timepulse Signal

Configurable Timepulse signal (one pulse per second by default). Leave open if not used.

EXTINT0 /SPEED

27 I Ext. Interrupt /Odometer

Ext. Interrupt Pin. Int. pull-up resistor to VCC. Leave open if unused. LEA-6R: Odometer speed

CFG_COM1 /NC /SPI_SCS2_N /TIMEPULSE2

9 I Config. Pin /NC /SPI /TIMEPULSE2

LEA-6S, LEA-6A: Leave open for default configuration. LEA-6H, LEA-6T-2: Do not connect

LEA-6R: SPI select 2 LEA-6T-0, LEA-6T-1: TIMEPULSE2

SDA2 /SPI_MOSI

I/O

DDC Pins /SPI

DDC Data. Leave open if not used. LEA-6R: SPI MOSI

SCL2 /SPI_MISO

I/O

DDC Pins /SPI

DDC Clock. Leave open if not used. LEA-6R: SPI MISO

Reserved

12 I

Leave open, do not drive low.

NC 5 Leave open for only LEA-6x design. Connect to VCC for backward compatibility to LEA-5x.

NC /FWD

21 Not Connect /Direction

Leave open LEA-6R: Forward / Backward indication

NC /SPI_ SCS1_N

22 Not Connect /SPI

Leave open LEA-6R: SPI select 1

NC /SPI_SCK

23 Not Connect /SPI

Leave open LEA-6R: SPI clock

2.2.1 Pin description for LEA-6 designs

Table 14: Pin description LEA-6

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Vcc

Micro

Processor

(serial)

Passive Antenna

Backup Battery

NEO-6

Top View

GND

Reserved

SS_N

TIMEPULSE

EXTINT0

USB_DM

USB_DP

VDDUSB

Reserved

VCC_RF

GND

RF_IN

GND

VCC

V_BCKP

RxD1

TxD1

SCL2

SDA2

Reserved

CFG_GPS0/SCK

MISO/CFG_COM1

MOSI/CFG_COM0

USB port (Optional)

Micro

Processor

(USB)

LDO

2.3 NEO-6 design

2.3.1 Passive antenna design (NEO-6)

This is a minimal setup for a PVT GPS receiver with a NEO-6 module.

Figure 24: NEO-6 passive antenna design (with USB)

The above design is for the USB in self-powered mode. For bus-powered mode pin 14 (CFG_COM0) must

be left open and VCC must be connected to VDDUSB. NMEA baud rate is 38400 when in self-powered mode.

For best performance with passive antenna designs use an external LNA to increase the sensitivity up to 2

dB. See Figure 25 and Figure 26.

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Vcc

Micro

Processor

(serial)

Passive Antenna

Backup Battery

NEO-6

Top View

GND

Reserved

SS_N

TIMEPULSE

EXTINT0

USB_DM

USB_DP

VDDUSB

Reserved

VCC_RF

GND

RF_IN

GND

VCC

V_BCKP

RxD1

TxD1

SCL2

SDA2

Reserved

CFG_GPS0/SCK

MISO/CFG_COM1

MOSI/CFG_COM0

USB port (Optional)

Micro

Processor

(USB)

LDO

LNA

SAW

Vcc

Micro

Processor

(serial)

Passive Antenna

Backup Battery

NEO-6

Top View

GND

Reserved

SS_N

TIMEPULSE

EXTINT0

USB_DM

USB_DP

VDDUSB

Reserved

VCC_RF

GND

RF_IN

GND

VCC

V_BCKP

RxD1

TxD1

SCL2

SDA2

(ANTOFF)

CFG_GPS0/SCK

MISO/CFG_COM1

MOSI/CFG_COM0

USB port (Optional)

Micro

Processor

(USB)

LDO

SAW

LNA

SAW

inverter

VCC

Figure 25: NEO-6 passive antenna design for best performance (with external LNA and SAW)

Figure 26 below shows a passive antenna design for NEO-6 GPS modules with an external SAW-LNA-SAW for best performance and increased immunity to jammers such as GSM. For lowest power in backup mode use ANTOFF

Figure 26: NEO-6 passive antenna design for best performance and increased immunity to jammers such as GSM

For information on increasing immunity to jammers such as GSM, see section 3.3.8.

When using an external LNA in PSM on / off mode, pin 17 can be programmed as ANTOFF.

To configure the ANTOFF function, refer to the u-blox 6 Receiver Description including Protocol

Specification [3].

Use caution when implementing ANTOFF configuration since forward compatibility is not

guaranteed

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Function

I/O

Description

Remarks

Power

VCC

23 I Supply Voltage

Max allowed ripple on VCC=50 mVpp

GND

10,12,13,24

Ground

Assure a good GND connection to all GND pins of the module, preferably with a large ground plane.

V_BCKP

22 I Backup voltage supply

It’s recommended to connect a backup battery to V_BCKP in order to enable Warm and Hot Start features on the receivers. Otherwise connect to GND.

VDDUSB

7 I USB Power Supply

To use the USB interface connect this pin to 3.0 – 3.6 V. If no USB serial port used connect to GND.

Antenna

RF_IN

11 I GPS signal input from antenna

The connection to the antenna has to be routed on the PCB. Use a controlled impedance of 50  to connect RF_IN to the antenna or the antenna connector.

VCC_RF

9 O Output Voltage RF section

Pins 8 and 9 must be connected together. VCC_RF can also be used to power an external active antenna.

UART TxD1

20 O Serial Port 1

Communication interface, can be programmed as TX ready for I2C interface.

RxD1

21 I Serial Port 1

Serial input. Internal pull-up resistor to VCC. Leave open if not used.

USB USB_DM

I/O

USB I/O line

USB2.0 bidirectional communication pin. Leave open if unused. Implementation see section 1.6.2

USB_DP

I/O

USB I/O line

System

TIMEPULSE

3 O Timepulse Signal

Configurable Timepulse signal (one pulse per second by default). Leave open if not used.

EXTINT0

4 I External Interrupt

External Interrupt Pin. Internal pull-up resistor to VCC. Leave open if not used.

SDA2

I/O

DDC Pins

DDC Data. Leave open, if not used.

SCL2

I/O

DDC Pins

DDC Clock. Leave open, if not used.

Reserved

I/O

Reserved

Can be configured as ANTOFF

CFG_COM1 /MISO

I/O

Config. Pin /SPI MISO

Leave open if not used.

CFG_COM0 /MOSI

I/O

Config. Pin /SPI MOSI

Leave open if not used. Note Connect to GND to use USB in Self Powered mode. See section 1.7.4 and the NEO-6 Data Sheet [3]

Reserved

8 I Reserved

Pins 8 and 9 must be connected together. Can be used as a

RESET_N input. See section 1.7.1

Reserved

1 - Reserved

Leave open.

SS_N

I/O

SPI Select

Leave open if not used.

CFG_GPS0 /SCK

I/O

Config. Pin /SPI SCK

Leave open if not used.

2.3.2 Pin description for NEO-6 designs

Table 15: Pinout NEO-6

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Vcc

Micro

Processor

(serial)

Passive Antenna

Backup Battery

Reserved

TIMEPULSE

EXTINT0

TxD1

VCC_IO

V_RESET

VCC_RF

GND

RF_IN

GND

VCC

V_BCKP

RxD1

ANTON

SCL2

SDA2

Reserved

MAX-6

Passive Antenna

LNA SAW

Vcc

Micro

Processor

(serial)

Backup Battery

Reserved

TIMEPULSE

EXTINT0

TxD1

VCC_IO

V_RESET

VCC_RF

GND

RF_IN

GND

VCC

V_BCKP

RxD1

ANTON

SCL2

SDA2

Reserved

MAX-6

SAW

Vcc

2.4 MAX-6 design

MAX-6 modules provide the following signals:

 ANTON Signal (to turn on and off external LNA). To save power consumption in Power Save mode. See

section 2.6.9.

 TX ready Signal (to trigger a host, e.g. a u-blox LEON wireless module, when data at DDC interface is ready

to be picked up). To save power consumption on Host side.

2.4.1 MAX-6 passive antenna design

This is a minimal setup for a PVT GPS receiver with a MAX-6 module.

Figure 27: MAX-6 passive antenna design

Figure 28: MAX-6 passive antenna design for best performance and increased immunity to jammers such as GSM

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For information on increasing immunity to jammers such as GSM, see section 3.3.8.

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Function

I/O

Description

Remarks

Power

VCC 8 I

Supply Voltage

Max allowed ripple on VCC=50 mVpp

GND

1,10,12

Ground

Assure a good GND connection to all GND pins of the module, preferably with a large ground plane.

V_BCKP

6 I Backup voltage supply

Backup voltage input pin. Connect to GND if not used.

Antenna

RF_IN

11 I GPS signal input from antenna

The connection to the antenna has to be routed on the PCB. Use a controlled impedance of 50  to connect RF_IN to the antenna or the antenna connector. DC block inside.

VCC_RF

14 O Output Voltage RF section

Can be used for active antenna or external LNA supply.

ANTON

13 O

Active antenna or ext. LNA control pin in power save mode. Int. pull-up resistor to VCC

UART TxD1

2 O Serial Port 1

UART, leave open if not used, Voltage level referred VCC_IO. Can be configured as TX ready indication for the DDC interface.

RxD1

3 I Serial Port 1

UART, leave open if not used, Voltage level referred VCC_IO

System

TIMEPULSE

4 O Timepulse Signal

Leave open if not used, Voltage level referred VCC_IO

EXTINT0

5 I External Interrupt

Leave open if not used, Voltage level referred VCC_IO SDA2

I/O

DDC Pins

DDC Data. Leave open, if not used.

SCL2

I/O

DDC Pins

DDC Clock. Leave open, if not used.

Reserved

18 Reserved

Leave open

VCC_IO

7 I

IO supply voltage Input must be always supplied. Usually connect to VCC Pin 8. If I/O level should be different from VCC, supply VCC_IO with the I/O level required.

V_RESET

9 I VRESET

Must be connected to VCC always. Can be used as reset input pin with additional circuit (connected to VCC by 3.3 k resistor). See section 1.7.1

Reserved

15 Reserved

Leave open

2.4.2 Pin description for MAX-6 designs

Table 16: Pinout MAX-6

2.5 Layout

This section provides important information for designing a reliable and sensitive GPS system. GPS signals at the surface of the Earth are about 15 dB below the thermal noise floor. Signal loss at the antenna

and the RF connection must be minimized as much as possible. When defining a GPS receiver layout, the placement of the antenna with respect to the receiver, as well as grounding, shielding and jamming from other digital devices are crucial issues and need to be considered very carefully.

2.5.1 Footprint and paste mask

Figure 29 - Figure 34 describe the footprint and provide recommendations for the paste mask for u-blox 6 LCC modules. These are recommendations only and not specifications. Note that the Copper and Solder masks have the same size and position.

To improve the wetting of the half vias, reduce the amount of solder paste under the module and increase the volume outside of the module by defining the dimensions of the paste mask to form a T-shape (or equivalent) extending beyond the Copper mask. For the stencil thickness, see section 3.2.1.

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17.0 mm [669 mil]

22.4 mm [881.9 mil]

1.0 mm [39 mil]

0.8 mm [31.5 mil]

2.45 mm

[96.5 mil]

1.1 mm

[43 mil]

3.0 mm

[118 mil]

2.15 mm

[84.5 mil]

0.8 mm

[31.5 mil]

Figure 29: LEA-6 footprint

Stencil: 150m

15.7 mm [618 mil]

17.0 mm [669 mil]

20.8 mm [819 mil]

0.8 mm [31.5

mil

]

0.6 mm [23.5

mil

]

Figure 30: LEA-6 paste mask

12.2 mm [480.3 mil]

16.0 mm [630

mil

]

1.0 mm

[39.3 mil]

0.8 mm [31.5

mil

]

0.8 mm

[31.5

mil

]

3.0 mm [118.1

mil

]

1.0 mm [39.3

mil

]

1.1 mm [43.3

mil

]

Figure 31: NEO-6 footprint

9.7 mm [382 mil]

10.1 mm [

398

mil

]

1.0 mm

[39.3 mil]

0.7 mm [

27.6

mil

]

0.8 mm

[31.5

mil

]

0.65 mm

[

26.6

mil

]

1.1 mm [43.3

mil

]

0.8 mm [

31.5

mil

]

Figure 32: MAX-6 footprint

Stencil: 150m

10.4 mm [409.5 mil]

14.6 mm [575 mil]

12.2 mm [480 mil]

0.8 mm [31.5

mil

]

0.6 mm [23.5

mil

]

Figure 33: NEO-6 paste mask

Stencil: 150m

7.9 mm [311 mil]

12.5 mm [492 mil]

9.7 mm [382 mil]

0.7 mm [27.6

mil

]

0.5 mm [19.7

mil

]

0.8 mm [31.5

mil

]

0.6 mm [23.5

mil

]

Figure 34: MAX-6 paste mask

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Non 'emitting'

circuits

PCB

Digital & Analog circuits

Non

'emitting'

circuits

Antenna

Digital Part

RF Part

RF & heat

'emitting'

circuits

PCB

Digital & Analog circuits

RF& heat 'emitting'

circuits

Antenna

MAX Form Factor (10.1 x 9.7 x 2.5): Same Pitch as NEO for all pins: 1.1 mm, but 4 pads in each corner

(pin 1, 9, 10 and 18) only 0.7 mm wide instead 0.8 mm

The paste mask outline needs to be considered when defining the minimal distance to the next

component. The exact geometry, distances, stencil thicknesses and solder paste volumes must be adapted to the specific production processes (e.g. soldering etc.) of the customer.

2.5.2 Placement

A very important factor in achieving maximum performance is the placement of the receiver on the PCB. The connection to the antenna must be as short as possible to avoid jamming into the very sensitive RF section.

Make sure that RF critical circuits are clearly separated from any other digital circuits on the system board. To achieve this, position the receiver digital part towards your digital section of the system PCB. Care must also be exercised with placing the receiver in proximity to circuitry that can emit heat. The RF part of the receiver is very sensitive to temperature and sudden changes can have an adverse impact on performance.

The RF part of the receiver is a temperature sensitive component. Avoid high temperature drift

and air vents near the receiver.

Figure 35: Placement (for exact pin orientation see data sheet)

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2.5.3 Antenna connection and grounding plane design

u-blox 6 modules can be connected to passive patch or active antennas. The RF connection is on the PCB and connects the RF_IN pin with the antenna feed point or the signal pin of the connector, respectively. Figure 36 illustrates connection to a typical five-pin RF connector. One can see the improved shielding for digital lines as discussed in the GPS Antenna Application Note [5]. Depending on the actual size of the ground area, additional vias should be placed in the outer region. In particular, the edges of the ground area should be terminated with a dense line of vias.

Figure 36: Recommended layout (for exact pin orientation see data sheet)

As seen in Figure 36, an isolated ground area is created around and below the RF connection. This part of the circuit MUST be kept as far from potential noise sources as possible. Make certain that no signal lines cross, and that no signal trace vias appear at the PCB surface within the area of the red rectangle. The ground plane should also be free of digital supply return currents in this area. On a multi layer board, the whole layer stack below the RF connection should be kept free of digital lines. This is because even solid ground planes provide only limited isolation.

The impedance of the antenna connection has to match the 50  impedance of the receiver. To achieve an impedance of 50 Ohms, the width W of the micro strip has to be chosen depending on the dielectric thickness H, the dielectric constant r of the dielectric material of the PCB and on the build-up of the PCB (see section 2.5.4). Figure 37 shows two different builds: A 2 Layer PCB and a 4 Layer PCB. The reference ground plane is in both designs on layer 2 (red). Therefore the effective thickness of the dielectric is different.

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Module

micro strip line

Ground plane

Module

micro strip line

Ground plane

PCB

Either don't use these layers or fillwith ground planes

Antenna

PCB

Figure 37: PCB build-up for micro strip line. Left: 2-layer PCB, right: 4-layer PCB

General design recommendations:

 The length of the micro strip line should be kept as short as possible. Lengths over 2.5 cm (1 inch) should be

avoided on standard PCB material and without additional shielding.

 For multi layer boards the distance between micro strip line and ground area on the top layer should at least

be as large as the dielectric thickness.

 Routing the RF connection close to digital sections of the design should be avoided.  To reduce signal reflections, sharp angles in the routing of the micro strip line should be avoided. Chamfers

or fillets are preferred for rectangular routing; 45-degree routing is preferred over Manhattan style 90-degree routing.

Wrong better best

Figure 38: Recommended micro strip routing to RF pin (for exact pin orientation see data sheet)

 Do not route the RF-connection underneath the receiver. The distance of the micro strip line to the ground

plane on the bottom side of the receiver is very small (some 100 µm) and has huge tolerances (up to 100%). Therefore, the impedance of this part of the trace cannot be controlled.

 Use as many vias as possible to connect the ground planes.  In order to avoid reliability hazards, the area on the PCB under the receiver should be entirely covered with

solder mask. Vias should not be open. Do not route under the receiver.

2.5.4 Antenna micro strip

There are many ways to design wave-guides on printed circuit boards. Common to all is that calculation of the electrical parameters is not straightforward. Freeware tools like AppCAD from Agilent or TXLine from Applied Wave Research, Inc. are of great help. They can be downloaded from www.agilent.com or http://www.hp.woodshot.com/ and www.mwoffice.com.

The micro strip is the most common configuration for printed circuit boards. The basic configuration is shown in Figure 39 and Figure 40. As a rule of thumb, for a FR-4 material the width of the conductor is roughly double the thickness of the dielectric to achieve 50  line impedance.

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–For the correct calculation of the micro strip impedance, one does not only need to consider the distance between the top and the first inner layer but also the distance between the micro strip and the adjacent GND plane on the same layer

Use the Coplanar Waveguide model for the calculation of the micro strip.

Figure 39: Micro strip on a 2-layer board (Agilent AppCAD Coplanar Waveguide)

Figure 39 shows an example of a 2-layer FR4 board with 1.6 mm thickness and a 35 µm (1 ounce) copper cladding. The thickness of the micro strip is comprised of the cladding (35µm) plus the plated copper (typically 25µm). Figure 40 is an example of a multi layer FR4 board with 18 µm (½ ounce) cladding and 180 µ dielectric between layer 1 and 2.

Figure 40: Micro strip on a multi layer board (Agilent AppCAD Coplanar Waveguide)

2.6 Antenna and antenna supervisor

u-blox 6 modules receive L1 band signals from GPS and GALILEO satellites at a nominal frequency of

1575.42 MHz. The RF signal is connected to the RF_IN pin. u-blox 6 modules can be connected to passive or active antennas.

For u-blox 6 receivers, the total preamplifier gain (minus cable and interconnect losses) must not exceed

50 dB. Total noise figure should be below 3 dB.

u-blox 6 Technology supports short circuit protection of the active antenna and an active antenna supervisor circuit (open and short circuit detection). For further information refer to Section 2.6.2).

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2.6.1 Passive antenna

A design using a passive antenna requires more attention regarding the layout of the RF section. Typically a passive antenna is located near electronic components; therefore care should be taken to reduce electrical ‘noise’ that may interfere with the antenna performance. Passive antennas do not require a DC bias voltage and can be directly connected to the RF input pin RF_IN. Sometimes, they may also need a passive matching network to match the impedance to 50 .

Some passive antenna designs present a DC short to the RF input, when connected. If a system is

designed with antenna bias supply AND there is a chance of a passive antenna being connected to the design, consider a short circuit protection.

All u-blox 6 receivers have a built-in LNA required for passive antennas.

Consider optional ESD protection (see section 3.3).

2.6.2 Active antenna (LEA-6)

Active antennas have an integrated low-noise amplifier. They can be directly connected to RF_IN. If an active antenna is connected to RF_IN, the integrated low-noise amplifier of the antenna needs to be supplied with the correct voltage through pin V_ANT. Usually, the supply voltage is fed to the antenna through the coaxial RF cable. Active antennas require a power supply that will contribute to the total GPS system power consumption budget with additional 5 to 20 mA typically. Inside the antenna, the DC component on the inner conductor will be separated from the RF signal and routed to the supply pin of the LNA (see Figure 41).

Figure 41: Active antenna biasing (for exact pin orientation see data sheet)

Generally an active antenna is easier to integrate into a system design, but an active antenna must also be placed far from any noise sources to have good performance.

Antennas should only be connected to the receiver when the receiver is not powered. Do not

connect or disconnect the Antenna when the u-blox 6 receiver is running as the receiver calibrates the noise floor on power-up. Connecting the antenna after power-up can result in prolonged acquisition time.

Never feed supply voltage into RF_IN on u-blox LEA-6 modules. Always feed via V_ANT.

To test GPS signal reacquisition, it is recommended to physically block the signal to the antenna, rather

than disconnecting and reconnecting the receiver.

Consider optional ESD protection; see section 3.3 for more information.

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u-blox 6 Module

GND

RF_IN

GND

Active Antenna

V_ANT

VCC_RF

LNA

R_BIAS

u-blox 6 Module

GND

RF_IN

GND

Active Antenna

V_ANT

VCC_RF

LNA

external antenna

voltage

supply

R_BIAS

2.6.3 Active antenna bias power (LEA-6)

There are two ways to supply the bias voltage to pin V_ANT. For Internal supply, the VCC_RF output must be connected to V_ANT to supply the antenna with a filtered supply voltage. However, the voltage specification of the antenna has to match the actual supply voltage of the u-blox 6 Receiver (e.g. 3.0 V).

Figure 42: Internal supply Antenna bias voltage (for exact pin orientation see data sheet)

Figure 43: External supplying Antenna bias voltage (for exact pin orientation see data sheet)

Since the bias voltage is fed into the most sensitive part of the receiver, i.e. the RF input, this supply should be virtually free of noise. Usually, low frequency noise is less critical than digital noise with spurious frequencies with harmonics up to the GPS/QZSS band of 1.575 GHz and GLONASS band of 1.602 GHz. Therefore, it is not recommended to use digital supply nets to feed pin V_ANT.

An internal switch (under control of the u-blox 6 software) can shut down the supply to the external antenna whenever it is not needed. This feature helps to reduce power consumption.

2.6.3.1 Short circuit protection

If a reasonably dimensioned series resistor R_BIAS is placed in front of pin V_ANT, a short circuit situation can be detected by the baseband processor. If such a situation is detected, the baseband processor will shut down supply to the antenna. The receiver is by default configured to attempt to reestablish antenna power supply periodically.

To configure the antenna supervisor use the UBX-CFG-ANT message. For further information refer to the

u-blox 6 Receiver Description including Protocol Specification [4].

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References

Value

Tolerance

Description

Manufacturer

R_BIAS

10 

 10%

Resistor, min 0.250 W

u-blox 6 Module

GND

RF_IN

GND

Active Antenna

V_ANT

VCC_RF

LNA

AADET_N

Antenna

Supervisor

Circuitry

external antenna

voltage

supply

Table 17: Short circuit protection, bill of material

Short circuits on the antenna input without limitation (R_BIAS) of the current can result in

permanent damage to the receiver! Therefore, it’s recommended to implement an R_BIAS in all

risk applications, such as situations where the antenna can be disconnected by the end-user or that have long antenna cables.

An additional R_BIAS is not required when using a short and open active antenna supervisor circuitry as

defined in Section 2.6.4.1, as the R_BIAS is equal to R2.

2.6.4 Active antenna supervisor (LEA-6)

u-blox 6 Technology provides the means to implement an active antenna supervisor with a minimal number of parts. The antenna supervisor is highly configurable to suit various different applications.

Figure 44: External antenna power supply with full antenna supervisor (for exact pin orientation see data sheet)

2.6.4.1 Short and open circuit active antenna supervisor

The Antenna Supervisor can be configured by a serial port message (using only UBX binary message). When enabled the active antenna supervisor produces serial port messages (status reporting in NMEA and/or UBX binary protocol) which indicates all changes of the antenna circuitry (disabled antenna supervisor, antenna circuitry ok, short circuit, open circuit) and shuts the antenna supply down if required. Active antenna status can be determined also polling UBX-MON-HW.

The active antenna supervisor provides the means to check the active antenna for open and short circuits and to shut the antenna supply off, if a short circuit is detected. The state diagram in Figure 45 applies. If an antenna is connected, the initial state after power-up is “Active Antenna OK”.

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Super-

vision

Active

Antenna

Open

Circuit

detected

Short

Circuit

detected

Powerup

Events AADET0_N

User controlled events

Disable Supervision

Enable Supervision

Short Circuit

detected

Disable

Supervision

Antenna connected

Short Circuit

detected

open circuit

detected, given

OCD enabled

Periodic

reconnection

attempts

Figure 45: State diagram of active antenna supervisor

Firmware supports an active antenna supervisor circuit, which is connected to the pin AADET_N. An example of an open circuit detection circuit is shown in Figure 46 and Figure 47. High on AADET_N means that an external antenna is not connected.

Short Circuit Detection (SCD)

A short circuit in the active antenna pulls V_ANT to ground. This is detected inside the u-blox 6 module and the antenna supply voltage will be immediately shut down.

Antenna short detection (SCD) and control is enabled by default.

Open Circuit Detection (OCD)

Figure 46: Schematic of open circuit detection variant A (for exact pin orientation see data sheet)

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References

Value

Tolerance

Description

Remarks

10 

 5%

Resistor, min 0.250 W

560 

 5%

Resistor

100 k

 5%

Resistor

LT6000

Rail to Rail Op Amp

Linear Technology

RFVcc

I _



 



 







GND

RF_IN

GND

V_ANT

VCC_RF

Active Antenna

ADDET_N

V_ANT

Antenna

Supply in

Analog GND

R3 R4 R5

T2 PNP

PNP

FB1

AADET_N

LEA-6x

Table 18: Active antenna supervisor, bill of material

Equation 1: Calculation of threshold current for open circuit detection

If the antenna supply voltage is not derived from Vcc_RF, do not exceed the maximum voltage rating of

AADET_N.

The open circuit detection circuit uses the current flow to detect an open circuit in the antenna. The threshold current can be calculated using Equation 1.

Figure 47: Schematic of open circuit detection variant B (for exact pin orientation see data sheet)

The open circuit supervisor circuitry shown in Figure 47 has a quiescent current of approximately 2mA.

This current can be reduced with an advanced circuitry such as shown in Figure 47.

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References

Value

Tolerance

Description

Remarks / Manufacturer

2.2 µF

 10%

Capacitor, X7R, min 10 V

100 nF

 10%

Capacitor, X7R, min 10 V

FB1

600 

Ferrite Bead

e.g. Murata BLM18HD601SN1

15 

 10%

Resistor, min 0.063 W

10 

 10%

Resistor, min 0.250 W

R3, R4

10 k

 10%

Resistor, min 0.063 W

33 k

 10%

Resistor, min 0.063 W

T1, T2

BC856B

PNP Transistor

e.g. Philips Semiconductors9

Abbreviation

Description

Antenna Control (e.g. the antenna will be switched on/ off controlled by the GPS receiver)

Short Circuit Detection Enabled

Short Circuit Recovery Enabled

Open Circuit Detection Enabled

PdoS

Power Down on short

Message

Description ANTSTATUS=DONTKNOW

Active antenna supervisor is not configured and deactivated.

ANTSTATUS=OK

Active antenna connected and powered

ANTSTATUS=SHORT

Antenna short

ANTSTATUS=OPEN

Antenna not connected or antenna defective

Table 19: Active antenna supervisor, bill of material

Status reporting

At startup and on every change of the antenna supervisor configuration the u-blox 6 GPS/GALILEO module will output a NMEA ($GPTXT) or UBX (INF-NOTICE) message with the internal status of the antenna supervisor (disabled, short detection only, enabled).

None, one or several of the strings below are part of this message to inform about the status of the active

antenna supervisor circuitry (e.g. “ANTSUPERV= AC SD OD PdoS”).

Table 20: Active Antenna Supervisor Message on startup (UBX binary protocol)

To activate the antenna supervisor use the UBX-CFG-ANT message. For further information refer to the

u-blox 6 Receiver Description including Protocol Specification [4].

Similar to the antenna supervisor configuration, the status of the antenna supervisor will be reported in a NMEA ($GPTXT) or UBX (INF-NOTICE) message at start-up and on every change.

Table 21: Active antenna supervisor message on startup (NMEA protocol)

2.6.5 Active antenna (NEO-6 and MAX-6)

NEO-6 and MAX-6 modules do not provide the antenna bias voltage for active antennas on the RF_IN pin. It is therefore necessary to provide this voltage outside the module via an inductor L as indicated in Figure 48. u-blox

recommends using an inductor from Murata (LQG15HS27NJ02). Alternative parts can be used if the inductor’s

resonant frequency matches the GPS frequency of 1575.42 MHz.

Transistors from other suppliers with comparable electrical characteristics may be used.

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Low Noise Amplifier

Active Antenna

RF_IN

VCC_RF

GND



R_BIAS

Low Noise Amplifier

Active Antenna

RF_IN

VCC_RF

GND

External antenna

supply

voltage

GND

Mic rostrip

GND

RF_IN

Antenna Supply Voltage

(e.g. VCC_RF)

Inductor L

GND

Antenna Supply Voltage

(e.g. VCC_RF)

Inductor L

Mic rostrip

RF_IN

Good Bad

Figure 48: Internal antenna bias voltage for active antennas

Figure 49: External antenna bias voltage for active antennas

For optimal performance, it is important to place the inductor as close to the microstrip as possible. Figure 50 illustrates the recommended layout and how it should not be done.

Figure 50: Recommended layout for connecting the antenna bias voltage for LEA-6M and NEO-6

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References

Value

Tolerance

Description

Remarks / Manufacturer

10 

 5%

Resistor, min 0.25 W

560 

 5%

Resistor

100 k

 5%

Resistor

100 k

 5%

Resistor

LT6000

Rail to Rail Op Amp

Linear Technology

Si1016X-T1-E3

Transistor

Vishay

LQG15HS27NJ02

Inductor

muRata

X5R 100N 10V

10%

Decoupling Capacitor

muRata

RFVcc

I _



 



 







2.6.6 External active antenna supervisor using ANTOFF (NEO-6)

Figure 51: External active antenna supervisor using ANTOFF (NEO-6)

Table 22: Active antenna supervisor, bill of material

Equation 2: Calculation of threshold current for open circuit detection

The state diagram of active antenna supervisor is in Figure 45. When using an external LNA in PSM on /

off mode, pin 17 can be programmed as ANTOFF (see section 1.7.7). Use ANTOFF_IN and ANTOFF_OUT signals to command antenna power supply when going into Power Save Mode (Backup mode).

Use caution when implementing ANTOFF configuration since forward compatibility is not

guaranteed

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References

Value

Tolerance

Description

Remarks / Manufacturer

10 

 5%

Resistor, min 0.25 W

560 

 5%

Resistor

100 k

 5%

Resistor

100 k

 5%

Resistor

LT6000

Rail to Rail Op Amp

Linear Technology

Si1016X-T1-E3

Transistor

Vishay

LQG15HS27NJ02

Inductor

muRata

X5R 100N 10V

10%

Decoupling Capacitor

muRata

RFVcc

I _



 



 







2.6.7 External active antenna supervisor using ANTON (MAX-6)

Figure 52: External active antenna supervisor using ANON (MAX-6)

Table 23: Active antenna supervisor, bill of material

Equation 3: Calculation of threshold current for open circuit detection

State diagram of active antenna supervisor see Figure 45. When using an external LNA in PSM on / off

mode, pin 17 can be programmed as ANTOFF (see section 1.7.7). Use ANTOFF_IN and ANTOFF_OUT signals to command antenna power supply when going into Power Save Mode (Backup mode).

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References

Value

Tolerance

Description

Remarks / Manufacturer

10 

 5%

Resistor, min 0.25 W

100 k

 5%

Resistor

Si1016X-T1-E3

Transistor

Vishay

LQG15HS27NJ02

Inductor

muRata

X5R 100N 10V

10%

Decoupling Capacitor

muRata

2.6.8 External active antenna control (NEO-6)

Figure 53: External active antenna control (NEO-6)

When using an external LNA in PSM on / off mode, pin 17 can be programmed as ANTOFF (see section

1.7.7).

Use caution when implementing ANTOFF configuration since forward compatibility is not

guaranteed

Table 24: Active antenna control, bill of material

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References

Value

Tolerance

Description

Remarks / Manufacturer

10 

 5%

Resistor, min 0.25 W

100 k

 5%

Resistor

Si1040X

Power MOSFET

Vishay

LQG15HS27NJ02

Inductor

muRata

X5R 1N 10V

10%

Decoupling Capacitor

muRata

2.6.9 External active antenna control (MAX-6)

ANTON Signal can be used to turn on and off an external LNA. This reduces power consumption in Power Save Mode (Backup mode).

Figure 54: External active antenna control (MAX-6)

Table 25: Active antenna control, bill of material

2.6.10 GPS antenna placement for LEA-6R

For an optimum ADR navigation performance, the following setup recommendations should be considered.

GPS antenna placement, gyro placement and single tick origin

Due to geometric and dynamic aspects of driving vehicles, it is important to correctly place the GPS antenna and the external sensors - from a geometric point of view - in order to get consistent measurement information from the different sensors.

For standard road vehicles: The GPS antenna should be placed above the middle of the rear (unsteered) axis. The gyro can be placed anywhere on the vehicle. Single ticks should origin from the rear (unsteered) wheels. For articulated busses, the sensors should be placed on the front car as if this was a standard road vehicle. In case the GWT solution is used for rail vehicles: The GPS antenna should be placed in the middle of a wagon, while the gyro can be placed anywhere on the same wagon and the single ticks can origin from any wheels of the same wagon.

Large geometrical deviations from the optimal placement - especially of the GPS antenna (e.g.

when placing it above the front axis of a long bus) - can result in significant performance degradation!

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3 Product handling

3.1 Packaging, shipping, storage and moisture preconditioning

For information pertaining to reels and tapes, Moisture Sensitivity levels (MSD), shipment and storage information, as well as drying for preconditioning see the data sheet of the specific u-blox 6 GPS module.

3.1.1 Population of Modules

When populating our modules make sure that the pick and place machine is aligned to the copper pins of

the module and not on the module edge.

3.2 Soldering

3.2.1 Soldering paste

Use of "No Clean" soldering paste is strongly recommended, as it does not require cleaning after the soldering process has taken place. The paste listed in the example below meets these criteria.

Soldering Paste: OM338 SAC405 / Nr.143714 (Cookson Electronics) Alloy specification: Sn 95.5/ Ag 4/ Cu 0.5 (95.5% Tin/ 4% Silver/ 0.5% Copper) Melting Temperature: 217°C Stencil Thickness: 150 µm for base boards The final choice of the soldering paste depends on the approved manufacturing procedures. The paste-mask geometry for applying soldering paste should meet the recommendations in section 2.5.1.

The quality of the solder joints on the connectors (’half vias’) should meet the appropriate IPC

specification.

3.2.2 Reflow soldering

A convection type-soldering oven is strongly recommended over the infrared type radiation oven.

Convection heated ovens allow precise control of the temperature and all parts will be heated up evenly, regardless of material properties, thickness of components and surface color.

Consider the "IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave) processes, published 2001".

Preheat phase

Initial heating of component leads and balls. Residual humidity will be dried out. Please note that this preheat phase will not replace prior baking procedures.

 Temperature rise rate: max.3°C/s If the temperature rise is too rapid in the preheat phase it may cause

excessive slumping.

 Time: 60 – 120 s If the preheat is insufficient, rather large solder balls tend to be

generated. Conversely, if performed excessively, fine balls and large balls will be generated in clusters.

 End Temperature: 150 - 200°C If the temperature is too low, non-melting tends to be caused in

areas containing large heat capacity.

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Heating/ Reflow phase

The temperature rises above the liquidus temperature of 217°C. Avoid a sudden rise in temperature as the slump of the paste could become worse.

 Limit time above 217°C liquidus temperature: 40 – 60 s  Peak reflow temperature: 245°C

Cooling phase

A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder and possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder fillets with a good shape and low contact angle.

 Temperature fall rate: max 4°C / s

To avoid falling off, the u-blox 6 GPS module should be placed on the topside of the motherboard during

soldering.

The final soldering temperature chosen at the factory depends on additional external factors like choice of soldering paste, size, thickness and properties of the base board, etc. Exceeding the maximum soldering temperature in the recommended soldering profile may permanently damage the module.

Figure 55: Recommended soldering profile

u-blox 6 modules must not be soldered with a damp heat process.

3.2.3 Optical inspection

After soldering the u-blox 6 module, consider an optical inspection step to check whether:

 The module is properly aligned and centered over the pads  All pads are properly soldered  No excess solder has created contacts to neighboring pads, or possibly to pad stacks and vias nearby.

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3.2.4 Cleaning

In general, cleaning the populated modules is strongly discouraged. Residues underneath the modules cannot be easily removed with a washing process.

 Cleaning with water will lead to capillary effects where water is absorbed in the gap between the baseboard

and the module. The combination of residues of soldering flux and encapsulated water leads to short circuits or resistor-like interconnections between neighboring pads.

 Cleaning with alcohol or other organic solvents can result in soldering flux residues flooding into the two

housings, areas that are not accessible for post-wash inspections. The solvent will also damage the sticker and the ink-jet printed text.

 Ultrasonic cleaning will permanently damage the module, in particular the quartz oscillators.

The best approach is to use a "no clean" soldering paste and eliminate the cleaning step after the soldering.

3.2.5 Repeated reflow soldering

Only single reflow soldering processes are recommended for boards populated with u-blox 6 modules. u-blox 6 modules should not be submitted to two reflow cycles on a board populated with components on both sides in order to avoid upside down orientation during the second reflow cycle. In this case the module should always be placed on that side of the board which is submitted into the last reflow cycle. The reason for this (besides others) is the risk of the module falling off due to the significantly higher weight in relation to other components.

Two reflow cycles can be considered by excluding the above described upside down scenario and taking into account the rework conditions described in Section 3.2.8.

Repeated reflow soldering processes and soldering the module upside down are not recommended.

3.2.6 Wave soldering

Base boards with combined through-hole technology (THT) components and surface-mount technology (SMT) devices require wave soldering to solder the THT components. Only a single wave soldering process is encouraged for boards populated with u-blox 6 modules.

3.2.7 Hand soldering

Hand soldering is allowed. Use a soldering iron temperature setting equivalent to 350°C. Place the module precisely on the pads. Start with a cross-diagonal fixture soldering (e.g. pins 1 and 15), and then continue from left to right.

3.2.8 Rework

The u-blox 6 module can be unsoldered from the baseboard using a hot air gun. When using a hot air gun for unsoldering the module, max 1 reflow cycle is allowed. In general we do not recommend using a hot air gun because this is an uncontrolled process and might damage the module.

Attention: use of a hot air gun can lead to overheating and severely damage the module.

Always avoid overheating the module.

After the module is removed, clean the pads before placing and hand-soldering a new module.

Never attempt a rework on the module itself, e.g. replacing individual components. Such

actions immediately terminate the warranty.

In addition to the two reflow cycles manual rework on particular pins by using a soldering iron is allowed. Manual rework steps on the module can be done several times.

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3.2.9 Conformal coating

Certain applications employ a conformal coating of the PCB using HumiSeal® or other related coating products. These materials affect the HF properties of the GPS module and it is important to prevent them from flowing into the module. The RF shields do not provide 100% protection for the module from coating liquids with low viscosity; therefore care is required in applying the coating.

Conformal Coating of the module will void the warranty.

3.2.10 Casting

If casting is required, use viscose or another type of silicon pottant. The OEM is strongly advised to qualify such processes in combination with the u-blox 6 module before implementing this in the production.

Casting will void the warranty.

3.2.11 Grounding metal covers

Attempts to improve grounding by soldering ground cables, wick or other forms of metal strips directly onto the EMI covers is done at the customer's own risk. The numerous ground pins should be sufficient to provide optimum immunity to interferences and noise.

u-blox makes no warranty for damages to the u-blox 6 module caused by soldering metal cables or any

other forms of metal strips directly onto the EMI covers.

3.2.12 Use of ultrasonic processes

Some components on the u-blox 6 module are sensitive to Ultrasonic Waves. Use of any Ultrasonic Processes (cleaning, welding etc.) may cause damage to the GPS Receiver.

u-blox offers no warranty against damages to the u-blox 6 module caused by any Ultrasonic Processes.

3.3 EOS/ESD/EMI Precautions

When integrating GPS receivers into wireless systems, careful consideration must be given to electromagnetic and voltage susceptibility issues. Wireless systems include components which can produce Electrical Overstress (EOS) and Electro-Magnetic Interference (EMI). CMOS devices are more sensitive to such influences because their failure mechanism is defined by the applied voltage, whereas bipolar semiconductors are more susceptible to thermal overstress. The following design guidelines are provided to help in designing robust yet cost effective solutions.

To avoid overstress damage during production or in the field it is essential to observe strict

EOS/ESD/EMI handling and protection measures.

To prevent overstress damage at the RF_IN of your receiver, never exceed the maximum input

power (see Data Sheet).

3.3.1 Abbreviations

For a list of abbreviations used see Table 28 in Appendix A.

3.3.2 Electrostatic discharge (ESD)

Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between two objects at different electrical potentials caused by direct contact or induced by an electrostatic field. The term is usually used in the electronics and other industries to describe momentary unwanted currents that may cause damage to electronic equipment.

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 Unless there is a galvanic coupling between the local GND (i.e. the

work table) and the PCB GND, the first point of contact when handling the PCB shall always be between the local GND and PCB GND.

 Before mounting an antenna patch, connect ground of the device.

GND

Local GND

 When handling the RF pin, do not come into contact with any

charged capacitors and be careful when contacting materials that can develop charges (e.g. patch antenna ~10 pF, coax cable ~5080 pF/m, soldering iron, …)

ESD

Sensitive!

RF_IN

 To prevent electrostatic discharge through the RF input, do not

touch any exposed antenna area. If there is any risk that such exposed antenna area is touched in non ESD protected work area, implement proper ESD protection measures in the design.

 When soldering RF connectors and patch antennas to the receiver’s

RF pin, make sure to use an ESD safe soldering iron (tip).

RF_IN

ESD Safe

3.3.3 ESD handling precautions

ESD prevention is based on establishing an Electrostatic Protective Area (EPA). The EPA can be a small working station or a large manufacturing area. The main principle of an EPA is that there are no highly charging materials in the vicinity of ESD sensitive electronics, all conductive materials are grounded, workers are grounded, and charge build-up on ESD sensitive electronics is prevented. International standards are used to define typical EPA and can be obtained for example from International Electrotechnical Commission (IEC) or American National Standards Institute (ANSI).

GPS receivers are sensitive to ESD and require special precautions when handling. Particular care must be exercised when handling patch antennas, due to the risk of electrostatic charges. In addition to standard ESD safety practices, the following measures should be taken into account whenever handling the receiver.

Failure to observe these precautions can result in severe damage to the GPS receiver!

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Small passive antennas (<2 dBic and performance critical)

Passive antennas (>2 dBic or performance sufficient)

Active Antennas

RF_IN

GPS

Receiver

LNA

RF_IN

GPS

Receiver

RF_IN

GPS

Receiver

LNA with appropriate ESD rating

3.3.4 ESD protection measures

GPS receivers are sensitive to Electrostatic Discharge (ESD). Special precautions are required

when handling.

For more robust designs, employ additional ESD protection measures. Using an LNA with appropriate ESD

rating can provide enhanced GPS performance with passive antennas and increases ESD protection.

Most defects caused by ESD can be prevented by following strict ESD protection rules for production and handling. When implementing passive antenna patches or external antenna connection points, then additional ESD measures as shown in Figure 56 can also avoid failures in the field.

Figure 56: ESD Precautions

Protection measure A is preferred because it offers the best GPS performance and best level of ESD

protection.

3.3.5 Electrical Overstress (EOS)

Electrical Overstress (EOS) usually describes situations when the maximum input power exceeds the maximum specified ratings. EOS failure can happen if RF emitters are close to a GPS receiver or its antenna. EOS causes damage to the chip structures.

If the RF_IN is damaged by EOS, it’s hard to determine whether the chip structures have been damaged by ESD or EOS.

3.3.6 EOS protection measures

For designs with GPS receivers and wireless (e.g. GSM/GPRS) transceivers in close proximity, ensure

sufficient isolation between the wireless and GPS antennas. If wireless power output causes the specified maximum power input at the GPS RF_IN to be exceeded, employ EOS protection measures to prevent overstress damage.

For robustness, EOS protection measures as shown in Figure 57 are recommended for designs combining wireless communication transceivers (e.g. GSM, GPRS) and GPS in the same design or in close proximity.

See C26 telematics reference design [12].

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Small passive antennas (<2 dBic and performance critical)

Passive antennas (>2 dBic or performance sufficient)

Active Antennas (without internal filter which need the module antenna supervisor circuits)

RF_IN

GPS

Receiver

LNA

GPS

Bandpas s

Filtler

RF_IN

GPS

Receiver

GPS

Bandpas s

Filtler

LNA with appropriate ESD rating and maximum input power

GPS Bandpass Filter: SAW or Ceramic with low insertion loss and appropriate ESD rating

GPS

Receiver

BLM15HD102SN1

>10mm

Figure 57: EOS and ESD Precautions

3.3.7 Electromagnetic interference (EMI)

Electromagnetic interference (EMI) is the addition or coupling of energy originating from any RF emitting device. This can cause a spontaneous reset of the GPS receiver or result in unstable performance. Any unshielded line or segment (>3mm) connected to the GPS receiver can effectively act as antenna and lead to EMI disturbances or damage.

The following elements are critical regarding EMI:

 Unshielded connectors (e.g. pin rows etc.)  Weakly shielded lines on PCB (e.g. on top or bottom layer and especially at the border of a PCB)  Weak GND concept (e.g. small and/or long ground line connections)

EMI protection measures are recommended when RF emitting devices are near the GPS receiver. To minimize the effect of EMI a robust grounding concept is essential. To achieve electromagnetic robustness follow the standard EMI suppression techniques.

http://www.murata.com/products/emc/knowhow/index.html http://www.murata.com/products/emc/knowhow/pdf/4to5e.pdf Improved EMI protection can be achieved by inserting a resistor (e.g. R>20 ) or better yet a ferrite bead

(BLM15HD102SN1) or an inductor (LQG15HS47NJ02) into any unshielded PCB lines connected to the GPS receiver. Place the resistor as close as possible to the GPS receiver pin.

Example of EMI protection measures on the RX/TX line using a ferrite bead:

Figure 58: EMI Precautions

VCC can be protected using a feed thru capacitor. For electromagnetic compatibility (EMC) of the RF_IN pin refer to section 3.3.6

Intended use

In order to mitigate any performance degradation of a radio equipment under EMC disturbance, system

integration shall adopt appropriate EMC design practice and not contain cables over three meters on signal and supply ports.

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

1525 1550 1625

GPS input filter characteristics

1575 1600

-110

Jammin g signal

1525 1550 1625

Frequency [MHz]

Power [dBm]

GPS input filter characteristics

1575 1600

Jamming

signal

GPS

signals

GPS Carrier

1575.4 MHz

3.3.8 Applications with wireless modules LEON / LISA

GSM uses power levels up to 2 W (+33 dBm). Consult the Data Sheet for the absolute maximum power input at the GPS receiver.

3.3.8.1 Isolation between GPS and GSM antenna

In a handheld type design an isolation of approximately 20dB can be reached with careful placement of the antennas. If such isolation can’t be achieved, e.g. in the case of an integrated GSM/GPS antenna, an additional input filter is needed on the GPS side to block the high energy emitted by the GSM transmitter. Examples of these kinds of filters would be the SAW Filters from Epcos (B9444 or B7839) or Murata.

3.3.8.2 Increasing jamming immunity

Jamming signals come from in-band and out-band frequency sources.

3.3.8.3 In-band jamming

With in-band jamming the signal frequency is very close to the GPS/QZSS band of 1.575 GHz and GLONASS band of 1.602 GHz (see Figure 59). Such jamming signals are typically caused by harmonics from displays, microcontroller, bus systems, etc.

Figure 59: In-band jamming signals

Figure 60: In-band jamming sources

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Measures against in-band jamming include:

 Maintaining a good grounding concept in the design  Shielding  Layout optimization  Filtering  Placement of the GPS antenna  Adding a CDMA, GSM, WCDMA bandpass filter before handset antenna

3.3.8.4 Out-band jamming

Out-band jamming is caused by signal frequencies that are different from the GPS carrier (see Figure 61). The main

sources are wireless communication systems such as GSM, CDMA, WCDMA, WiFi, BT, etc.

Figure 61: Out-band jamming signals

Measures against out-band jamming include maintaining a good grounding concept in the design and adding a SAW or bandpass ceramic filter (as recommend in Section 3.3.6) into the antenna input line to the GPS receiver (see Figure 62).

Figure 62: Measures against in-band jamming

3.3.8.5 GPS and GSM solution with integrated SMT antennas and chip SIM

An example is available on our C16 telematics reference design [12], that combines LEON-G200 GSM/GPRS modem module with NEO-6Q GPS receiver module.

UBX-14054794 Production Information Product handling Page 62 of 85

3.3.9 Recommended parts

Manufacturer

Part ID

Remarks

Parameters to consider

Diode ON Semiconductor

ESD9R3.3ST5G

(3.3.4 C) Standoff Voltage>3.3 V

• Low Capacitance < 0.5 pF

ESD9L3.3ST5G

(3.3.4 C) Standoff Voltage>3.3 V

• Standoff Voltage > Voltage for

active antenna

ESD9L5.0ST5G

(3.3.4 C) Standoff Voltage>5 V

• Low Inductance

SAW

Epcos B9444: B39162-B9444-M410

(3.3.6) 15dBm Max Power Input

B9416: B39162-B9416-K610

(3.3.6) Low insertion loss

B8401: B39162-B8401-P810

GPS and GLONASS

Murata

SAFEA1G57KD0F00

(3.3.6) 1.35x1.05x0.5 mm

SAFZE1G57KA0F90

(3.3.6) 2.5x2.0x1.0 mm

SAFEB1G57KB0F00

(3.3.6) 1.35x1.05x0.6 mm

SAFEA1G57KE0F00

(3.3.6) 1.35x1.05x0.45 mm

•Good wireless band suppression

SAFFB1G58KA0F0A

GPS and GLONASS

•High attenuation

SAFEA1G58KA0F00

GPS and GLONASS

•High attenuation

CTS

CER0032A

(3.3.6) 4.2x4.0x2.0 mm > 8kV ESD HBM

LNA

Avago

ALM-1106

(3.3.4 A) LNA

pHEMT (GaAS)

ALM-1412

(3.3.6 D) LNA + FBAR Filter

ALM-1712

(3.3.6 D) Filter + LNA + FBAR Filter

ALM-2412

(3.3.4 A) LNA + FBAR Filter

MAXIM

MAX2659ELT+

(3.3.4 A) LNA

SiGe

JRC

NJG1143UA2

LNA

Infineon

BGM1032N16

Filter + LNA

BGM981N11

Filter + LNA + Filter

BGM1052N16

LNA + Filter

Triquint

TQM640002

Filter + LNA + Filter

Inductor

Murata

LQG15HS27NJ02

(3.3.6 F) L, 27 nH

Impedance @ freq GPS > 500 

Capacitor

Murata

GRM1555C1E470JZ01

(3.3.6 F) C, 47 pF

Ferrite Bead

Murata

BLM15HD102SN1

(3.3.7) FB

High IZI @ fGSM

Feed thru Capacitor for Signal Murata

NFL18SP157X1A3

Monolithic Type Array Type

Load Capacitance appropriate to Baud rate CL < xxx pF

NFA18SL307V1A45

Feed thru Capacitor

for VCC

Murata

NFM18PC …. NFM21P….

0603 2A 0805 4A

Rs < 0.5 

Manufacturer

Order No.

Comments

Inpaq (www.inpaq.com.tw)

GPSGLONASS03D-S3-00-A

25*25*4mm, 2.7 to 3.9 V 6 mA at 3.3V

Taoglas (www.taoglas.com)

AA.160.301111

36*36*6mm, 3 to 5V / 30mA at 5V

Taoglas (www.taoglas.com)

AA.161.301111

36*36*3mm, 1.8 to 5.5V / 10mA at 3V

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Table 26: Recommended parts for ESD/EOS protection

3.3.9.1 Recommended GPS & GLONASS active antenna (A1)

Table 27: Recommend GPS & GLONASS active antenna (A1). If possible, using a 36*36 mm patch antenna is preferred.

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

3.4 Safety precautions

LEA-6 / NEO-6 / MAX-6 modules must be supplied by an external limited power source in compliance with the clause 2.5 of the standard IEC 60950-1. In addition to external limited power source, only separated or Safety Extra-Low Voltage (SELV) circuits are to be connected to the module, including interfaces and antennas.

For more information about SELV circuits, see section 2.2 in Safety standard IEC 60950-1 [15].

UBX-14054794 Production Information Product handling Page 64 of 85

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

4 Product testing

4.1 u-blox in-series production test

u-blox focuses on high quality for its products. To achieve a high standard it’s our philosophy to supply fully tested units. Therefore at the end of the production process, every unit is tested. Defective units are analyzed in detail to improve the production quality.

This is achieved with automatic test equipment, which delivers a detailed test report for each unit. The following measurements are done:

 Digital self-test (Software Download, verification of FLASH firmware, etc.)  Measurement of voltages and currents  Measurement of RF characteristics (e.g. C/No)

Figure 63: Automatic Test Equipment for Module Tests

4.2 Test parameters for OEM manufacturer

Because of the testing done by u-blox (with 100% coverage), an OEM manufacturer doesn’t need to repeat firmware tests or measurements of the GPS parameters/characteristics (e.g. TTFF) in their production test.

An OEM manufacturer should focus on:

 Overall sensitivity of the device (including antenna, if applicable)  Communication to a host controller

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

4.3 System sensitivity test

The best way to test the sensitivity of a GPS device is with the use of a 1-channel GPS simulator. It assures reliable and constant signals at every measurement.

Figure 64: 1-channel GPS simulator

u-blox recommends the following Single-Channel GPS Simulator:

 Spirent GSS6100 (GPS)  Spirent GSS6300 (GPS/GLONASS)

Spirent Communications Positioning Technology www.spirent.com

4.3.1 Guidelines for sensitivity tests

1. Connect a 1-channel GPS/GLONASS simulator to the OEM product

2. Choose the power level in a way that the “Golden Device” would report a C/No ratio of 38-40 dBHz

3. Power up the DUT (Device Under Test) and allow enough time for the acquisition

4. Read the C/No value from the NMEA GSV or the UBX-NAV-SVINFO message (e.g. with u-center)

5. Compare the results to a “Golden Device” or a u-blox 6 Evaluation Kit.

4.3.2 ‘Go/No go’ tests for integrated devices

The best test is to bring the device to an outdoor position with excellent sky view (HDOP < 3.0). Let the

receiver acquire satellites and compare the signal strength with a “Golden Device”.

As the electro-magnetic field of a redistribution antenna is not homogenous, indoor tests are in most

cases not reliable. These kind of tests may be useful as a ‘go/no go’ test but not for sensitivity

measurements.

4.3.3 Testing LEA-6R designs

When testing the design ensure that no GPS signals are being received or delete the calibration after the

tests. Failure to do so can result in operation errors.

4.3.3.1 Direction signal

This input shall be set once to high level and once to low level. In both states the software parameters are read back with the UBX-NAV-EKFSTATUS. The direction flag shall read forward for a high level at the FWD input and backward for a low level at the FORWARD input.

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

4.3.3.2 Speedpulse signal

A rectangular waveform with 2 kHz frequency shall be fed into the SPEED input. The result can be read back with the UBX-NAV-EKFSTATUS message: Speed Ticks: 1800...2400

4.3.3.3 Gyroscope (rate) input

Do not move the device and check UBX-ESF-MEAS: 2 > Gyro Z: > -2 Quickly turn the device to the right (clockwise), check UBX-ESF-MEAS: Gyro Z: > 50 Quickly turn the device to the left (counterclockwise), check UBX-ESF-MEAS: Gyro Z: < -50

The rate input can only be tested if an A/D converter is connected to LEA-6R.

4.3.3.4 Temperature sensor

The temperature measured by the temperature sensor connected to the LEA-6R shall be read with the UBX-ESFMEAS message. The measurement tolerance is in the order of about ±5°.

4.3.3.5 Erase calibration

To erase the calibration send a CFG-EKF command with the appropriate clearing flags set.

4.3.4 Testing NEO-6V designs

The NEO-6V ADR algorithm supports a variety of sensors (such as wheel ticks and gyroscope) and receives the sensor data via UBX messages from the application processor. Digital sensor data is available on the vehicle bus. No extra sensors are required for Dead Reckoning functionality. ADR is completely self-calibrating.

For more details on GWT protocol, see u-blox 6 Receiver Description Including Protocol Specification [13] For more details on DWT protocol, contact u-blox. (Contact)

UBX-14054794 Production Information Product testing Page 67 of 85

Appendix

Abbreviation

Definition ANSI

American National Standards Institute

CDMA

Code Division Multiple Access

EMC

Electromagnetic compatibility

EMI

Electromagnetic interference

EOS

Electrical Overstress

EPA

Electrostatic Protective Area

ESD

Electrostatic discharge

GND

Ground

GPS

Global Positioning System

GSM

Global System for Mobile Communications

IEC

International Electrotechnical Commission

PCB

Printed circuit board

A Abbreviations

Table 28: Explanation of abbreviations used

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

B Migration to u-blox-6 receivers

Migrating ANTARIS®4 and u-blox 5 designs to a u-blox 6 receiver module is a fairly straightforward procedure. Nevertheless there are some points to be considered during the migration.

Not all of the functionalities available with ANTARIS®4 are supported by u-blox 6. These include:

 RTCM is supported in FW7.0x but not in ROM6.02 and FW6.02 versions.  UTM (Universal Transverse Mercator Projection)

B.1 Checklist for migration

Have you chosen the optimal module?

 For best GPS performance (i.e. better sensitivity level and acquisition time) select a LEA-6H, LEA-6S, NEO-

6Q or NEO-6G for the advantage of TCXO performance.

 If TCXO performance is not required, choose a LEA-6A or NEO-6M.  For active antenna applications, choose a LEA-6H, LEA-6S or LEA-6A, since an antenna supply circuit is

already built in or see section 1.4 and section 2.6.

 For the ability to upgrade the firmware, choose a LEA-6H.  For precision timing choose a LEA-6T or NEO-6T  For dead reckoning choose a LEA-6R

UBX-14054794 Production Information Appendix Page 68 of 85

u-blox 6

NEO-4S

NEO

NEO-6M/Q

LEA

• Flash memory, Antenna Supervisor

LEA-6H

LEA-6A/S

• ROM, Antenna Supervisor

LEA-4T

LEA-4R

LEA-6T

LEA-6R

• Precision Timing

• Dead Reckoning

NEO-5D/G NEO-6G

ROM, 3.0 V

ROM, 1.8 V

•

ROM

u-blox 5

ANTARI S 4

NEO-5M/Q

LEA-5T

LEA-4P/H

LEA-5H

LEA-4A/S

LEA-5A/S

LEA-4M LEA-5M/Q

Figure 65: u-blox 6 module migration made easy

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

Check u-blox 6 Hardware Requirements:

 Check the battery power to supply the battery backup pin, since u-blox 6 draws higher current in

comparison to ANTARIS 4 receivers.

 Compare the u-blox 6 module peak current consumption (~70 mA) with the specification of the power

supply.

 u-blox 6 modules can be operated in three different modes: Max. Performance mode, Eco mode or

Power Save mode.

 NEO-6Q, NEO-6G and NEO-6M feature a Configuration Pin that allows switching between the power

modes: Max Performance mode and Eco mode.

 For more information on u-blox6 Power supply specifications and power modes, see the LEA-6 Data

Sheet [1] and NEO-6 Data Sheet [3].

 If you use an active antenna supervisor circuitry to detect open conditions, you need to verify resistor

reference recommendations in our integration manuals.

 See section 3.3 EOS/ESD/EMI Precautions.  If you use the USB interface, the external series resistor values in USB_DM and USB_DP line should be

adjusted, see section 1.6.2.

Check u-blox 6 Software Requirements:

 Not all of the functionalities available with ANTARIS 4 are supported by u-blox 6 Firmware version 6.02.

These include:

o FixNow Mode: Low power modes are supported via mapping to the Power Save mode of

FW 7.0x or ROM 6.02. For migration of FXN functionalities consult the u-blox 6 Firmware

Version 7.0x Release Note [8], respectively the u-blox 6 Receiver Description including Protocol Specification [4]

o No UTM (Universal Transverse Mercator Projection). o No RTCM protocol for DGPS support (ROM6.02, FW6.02). o Raw Data support with LEA-6T only.

 Check B.2 Software migration

UBX-14054794 Production Information Appendix Page 69 of 85

B.2 Software migration

ANTARIS 4

u-blox6

Remarks

UBX-CFG-NAV2

UBX-CFG-NAV5

UBX-CFG-NAV2 has been replaced by UBX-CFG-NAV5. The new message has additional features.

The default dynamic platform is “Portable”. This platform is rather generic

and allows the receiver to be operated in a wide dynamic range covering pedestrians, cars as well as commercial aircrafts. Automotive applications such as first-mount navigation systems may better utilize the “Automotive” platform, which is better geared to the dynamics of land vehicles but is only of limited use in airborne and high-dynamics environments. UBX-CFG-NAV5 does not support following features: Almanac Navigation Navigation Input filters UBX-CFG-NAV5 has a message length of 36 Bytes (40 Bytes for UBX-CFGNAV2) UBX-CFG-NAV5 FixMode is set by default to “Auto 3D/2D” as for ANTARIS4. Check the u-blox 6 Receiver Description including Protocol Specification [4]. if this mode needs to be changed.

UBX-CFG-MSG

No support for multiple configurations in one UBX-CFG-MSG command

UBX-CFG-RXM

N/A

Contrary to ANTARIS 4, u-blox6 does not need selecting GPS acquisition sensitivity mode (Fast, Normal, High Sens and Auto mode) since the acquisition engine is powerful enough to search all satellite in one go. FixNow mode is not available anymore. Contact your local u-blox support team should you need further information.

PUBX,01

N/A

Other UBX or NMEA messages can be used to replace this message

UBX-NAV-POSUTM

N/A

UBX-CFG-TP

u-blox 6 maintains this message for backwards compatibility only. For new designs use UBX-CFG-TP5.

UBX-CFG-TP5

This is a new u-blox 6 message, for information see u-blox 6 Receiver Description including Protocol Specification [4].

UBX-CFG-ANT

Antenna Open Circuit Detection: The default setting for LEA-4S and LEA-4A

was “enabled”. With all LEA-6 modules the default setting is “disabled”.

Automatic Short Circuit Recovery: With ANTARIS 4 this was “disabled” by

default. With u-blox 6 the default setting is “enabled”.

UBX-CFG-RATE

UBX-CFG- RATE

Set to 1 with u-blox 6

UBX-CFG-TMODE

With u-blox 6 FW 6.02 and above it is no longer necessary to configure the number of satellites in UBX-CFG-NAV to 1 to enable the timing mode. This is performed automatically.

UBX-MON-HW

Message length has changed as the number of pins is different with u-blox6.

0s Leap second by default

FW 6.02 and FW7.0x: 15 s Leap second by default

UBX-CFG-RATE

Disable SBAS services to achieve 4Hz navigation

UBX-NAV- EKFSTATUS

This message is only provided for backwards compatibility and should not be utilized for future designs. Instead, the messages ESF-STATUS and ESF-MEAS should be used. For u-blox 6 firmware the gyroscope value (gyroMean) is only output if the gyroscope is used in the navigation solution. This message is only available on LEA-4R and LEA-6R GPS Receivers.

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

B.2.1 Software migration from ANTARIS

4 or u-blox 5 to a u-blox 6 GPS receiver

Software migration from ANTARIS 4 or u-blox 5 to a u-blox 6 GPS receiver is a straightforward procedure. Nevertheless there are some differences to be considered with u-blox 5 firmware version 5.00. Like its ANTARIS 4 and u-blox 5 predecessors, u-blox 6 technology supports UBX and NMEA protocol messages. Backward compatibility has been maintained as far as possible. New messages have been introduced for new functions. Only minor differences have to be expected in the UBX-NAV and UBX-AID classes of the UBX protocol and for the standard NMEA messages such as GGA, GLL, GSA, GSV, RMC, VTG and ZDA.

Table 29: Main differences between ANTARIS 4 and u-blox 6 software for migration

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

The default NMEA message set for u-blox 6 is GGA, GLL, GSA, GSV, RMC and VTG. Contrary to ANTARIS 4, ZDA is disabled by default.

Firmware update is supported by all of these interfaces. The firmware update mechanism of u-blox 6 is more sophisticated than with ANTARIS 4. It is now based on UBX protocol messages. Customers, who implemented firmware download in their application processor, will need to replace the software. A template is available from your u-blox support team.

In case migrating from LEA-4T or LEA-5T to LEA-6T-0, the command to save the configuration (UBX-CGF-CFG) changes. This is because in LEA-6T-0 a serial Flash at the SPI is used instead of the parallel Flash (LEA-4T and LEA5T). So for the LEA-4T, LEA-5T, LEA-6T-1 and LEA-6T-2 the target to save the configuration has to be set to “devFlash”, but for the LEA-6T-0 it has to be set to “devSpiFlash”.

Please refer to the u-blox 6 Receiver Description including Protocol Specification [4] for more information. This document is available on the u-blox website.

B.2.2 Software migration from 6.02 to 7.03

Timing Survey-in Mode: Customers using survey-in should review the changes in the accuracy limit parameters in CFG-TMODE and CFG-

TMODE2 in FW 7.03, as described in the u-blox 6 Firmware Version 7.0x Release Note [8], and the u-blox 6 Receiver Description including Protocol Specification [4]

B.2.3 Software migration from 7.03 to FW1.00 GLONASS, GPS & QZSS

When migrating from 7.03 to FW1.00 GLONASS, GPS & QZSS consult the GPS/GLONASS/QZSS Firmware 1.00 for u-blox 6 Release Note [7], and the u-blox 6 Receiver Description including Protocol Specification (GPS/GLONASS/QZSS) [5].

B.3 Hardware Migration

B.3.1 Hardware Migration: ANTARIS 4  u-blox 6

u-blox 6 modules have been designed with backward compatibility in mind but some minor differences were unavoidable. These minor differences will however not be relevant for the majority of the ANTARIS 4 designs.

Good performance requires a clean and stable power supply with minimal ripple. Care needs to be exercised in selecting a strategy to achieve this. Avoid placing any resistance on the Vcc line. For better performance, use an LDO to provide a clean supply at Vcc and consider the following:

 Special attention needs to be paid to the power supply requirements. (currents & backup current see data

sheet for further details)

 Wide power lines or even power planes are preferred.  Place LDO near the module.  Avoid resistive components in the power line (e.g. narrow power lines, coils, resistors, etc.).

Placing a filter or other source of resistance at Vcc can create significantly longer acquisition

times.

B.3.2 Hardware Migration: u-blox 5  u-blox 6

Check the pins RxD1 and EXTINT0 regarding the input voltage threshold. Serial termination resistors: Recommendation has changed from 27  to 22 . See section 1.6.2.1. For more information see the LEA-6 Data Sheet [1] and LEA-5 Data Sheet [10].

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LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

LEA-4H/LEA-4P/LEA-4T

LEA-6H/LEA-6T

Remarks for Migration

Pin Name

Typical Assignment

Pin Name

Typical Assignment

Reserved

VDDIO level I/O; not connected

SDA2

NC 2

Reserved

VDDIO level I/O; not connected

SCL2

TXD1

VDDIO level I/O

TxD1

Output

4 RXD1

VDDIO level I/O

RxD1

Input

Leave open if not used.

VDDIO

1.65 – 3.60 V

Connect to VCC

Can be left open, but connection to VCC is recommended for compatibility reason. With LEA6H the I/O voltage is always VCC.

VCC

2.70 – 3.30 V

VCC

2.70 – 3.60 V

Extended power supply range, higher peak supply current.

GND

No difference

VDD18OUT

VCC_OUT

Internally connected to VCC, if you have circuitry connected to this pin, check if it withstands the VCC voltage.

Reserved

RESET_N

1.8 V

RESET_N

Input only, do not drive high. Internal pull up to VCC.

V_BAT

1.50 – 3.6 V

V_BCKP

1.4 – 3.6 V

Wider voltage range but needs more current. Check your backup supply, regarding the higher consumption.

BOOT_INT

Reserved

Do not drive low.

GND

No difference

GND

No difference

GND

No difference

RF_IN

No difference

GND

No difference

VCC_RF

VCC – 0.1 V

VCC_RF

VCC – 0.1 V

No difference

V_ANT

3.0 V –5.0 V

V_ANT

2.7 V -5.5 V

wider range

AADET_N

check resistor R5 in Active antenna supervisor Figure 47

EXTINT1

Reserved

VDDUSB

Connected to GND or VDD_USB

VDDUSB

Connected to GND or VDD_USB

Do not leave open. (VDD_USB is 3.3V regulated power supply from VBUS.)

USB_DM

New serial termination resistors recommended: 22 

USB_DP

EXTINT0

TIMEPULSE

VDDIO level I/O

TIMEPULSE

Output

B.4 Migration of LEA modules

B.4.1 Migration from LEA-4 to LEA-6

See also the migration Table in the u-blox5 Hardware Integration Manual. For u-blox6 the Input Voltage thresholds on the pins RXD1 and EXTINT0 have changed. The Safeboot functionality is inverted compared to Antaris receivers. VCC_OUT is now VCC and not 1.8 V as on Antaris Modules. Also check your power supply requirements with the datasheet (for VCC and VBCKP).

Table 30: Pin-out comparison LEA-4H/LEA-4P/LEA-4T vs. LEA-6H/LEA-6T

UBX-14054794 Production Information Appendix Page 72 of 85

LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual

LEA-4A/LEA-4S

LEA-6A/LEA-6S

Remarks for Migration

Pin Name

Typical Assignment

Pin Name

Typical Assignment

TxD2

3.0 V out

SDA2

RxD2

1.8 – 5.0 V

SCL2

TxD1

3.0 V out

TxD1

Output

4 RxD1

1.8 – 5.0 V in

RxD1

Input

Leave open if not used. Max. 5 V

VDDIO

VCC

Connect to VCC

Leave open for only LEA-6x design. Connect to VCC for backward compatibility to LEA-5x.

VCC

2.70 – 3.30 V

VCC

2.70 – 3.60 V

Extended power supply range, higher peak supply current.

GND

No difference

VDD18OUT

1.8 V out

VCC_OUT

Internally connected to VCC, if you have circuitry connected to this pin, check if it withstands the VCC voltage.

GPSMODE6

NC (GND or VDD18OUT)

CFG_COM1

NC 10

RESET_N

ACTIVE LOW

RESET_N

Input only, do not drive high. Internal pull up to VCC.

V_BAT

1.50 – 3.6 V

V_BCKP

1.4 – 3.6 V

Wider voltage range but needs more current. Check your backup supply, regarding the higher consumption.

BOOT_INT

Reserved

Do not drive low.

GND

No difference

GND

No difference

GND

No difference

RF_IN

No difference

GND

No difference

VCC_RF

VCC – 0.1 V

VCC_RF

VCC – 0.1V

No difference

V_ANT

3.0 V – 5.0 V

V_ANT

2.7V -5.5V

wider range

AADET_N

NC (1.8 to 5.0 V)

AADET_N

check resistor R5 in Active antenna supervisor Figure 47

GPSMODE5

NC (GND or VDD18OUT)

GPSMODE2 GPSMODE2 3

NC (GND or VDD18OUT)

GPSMODE7

NC (1.8 to 5.0 V)

VDDUSB

3.0 –3.6V/ GND

VDDUSB

Connected to GND or VDD_USB

Do not leave open. (VDD_USB is 3.3 V regulated power supply from VBUS.)

USB_DM

VDDUSB I/O

USB_DM

New serial termination resistors recommended: 22 

USB_DP

VDDUSB I/O

USB_DP

EXTINT0

NC (1.8 to 5.0 V)

EXTINT0

Max. 5 V

TIMEPULSE

VDDIO level output

TIMEPULSE

Output

Table 31: Pin-out comparison LEA-4A/LEA-4S vs. LEA-6A/LEA-6S

B.4.2 Migration of LEA-4R designs to LEA-6R

LEA-6R module has been designed with backward compatibility in mind, but some incompatibilities were unavoidable. These minor differences will, however, not be relevant for the majority of ANTARIS 4 designs.

Please check in your design the following points carefully to assure a safe migration:

 For u-blox 6 the Input Voltage thresholds on the pins RxD1 and Extint0 have changed.  VCC_OUT is now VCC and not 1.8 V as on Antaris Modules.  Pin5 is now NC instead of VDDIO. All I/O Voltages are referenced to VCC.  Check your power supply requirements with the datasheet (for VCC and VBCKP), u-blox 6 has a higher

peak current and backup current than ANTARIS 4 modules

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NEO-4S

NEO-6Q/NEO-6M

Remarks for Migration

Pin Name

Typ. Assignment

Pin Name

Typ. Assignment

1 BOOT_INT

Reserved

Do not drive low.

SELECT

VDDIO level I/O; not connected

SS_N

TIMEPULSE

VDDIO level I/O

TIMEPULSE

Output

EXTINT0

USB_DM

New serial termination resistors recommended: 22 Ohms

USB_DP

VDDUSB

Connected to GND or VDD_USB

VDDUSB

Connected to GND or VDD_USB

Do not leave open. (VDD_USB is 3.3V regulated power supply from VBUS.)

Reserved

Pins 8 and 9 must be connected.

VCC_RF

VCC-0.1 V

VCC_RF

VCC-0.1 V

No difference

GND

No difference

RF_IN

No difference

GND

No difference

GND

No difference

MOSI

MOSI/CFG_COM0

The function of the CFG pin has changed. See section 2.2.3.1 for more details.

MISO

MISO/CFG_COM1

SCK/ CFG_USB

CFG_GPS0 /SCK

Leave open if not used. The function of the CFG pin has changed. See section 2.2.3.1 for more details.

NCS

Reserved

No difference

Reserved

SDA2

Reserved

SCL2

TXD1

VDDIO level I/O

TxD1

Output

RXD1

VDDIO level I/O

RxD1

Input

Leave open if not used.

V_BAT

1.5-3.6 V

V_BCKP

1.4-3.6 V

Wider voltage range but needs more current. Check your backup supply, regarding the higher consumption.

VCC

2.7-3.3 V

VCC

2.7-3.6 V

Higher peak supply current

GND

No difference

 The SPI is now running at 870 kHz (against 460 kHz on ANTARIS 4), check that your design supports the

signal path

 If you do a redesign, ensure the signal paths of the SPI to support a bandwidth of 4 MHz.

B.4.3 Migration from LEA-5 to LEA-6

For u-blox6 only the Input Voltage thresholds on the pins RXD1 and EXTINT0 have changed. Be aware, that with u-blox 6 there is no LEA anymore, which supports SPI interface. For SPI consider NEO-6 form

factor.

B.5 Migration of NEO modules

B.5.1 Migration from NEO-4S to NEO-6

For u-blox6 the Input Voltage thresholds on the pins RXD1 and EXTINT0 have changed. The Safeboot functionality is inverted compared to Antaris receivers. Also check your power supply requirements with the datasheet (for VCC and VBCKP). Also check the setting of the configuration pins. The pin-outs of NEO-4S and NEO-6M/NEO-6Q differ slightly. Table 32 compares the modules and highlights the

differences to be considered.

Table 32: Pin-out comparison NEO-4S vs. NEO-6

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B.5.2 Migration from NEO-5 to NEO-6

For u-blox 6 only the Input Voltage thresholds on the pins RXD1 and EXTINT0 have changed. Also check the setting of the configuration pins. Serial termination resistors: Recommendation has changed from 27  to 22 . See section 1.6.2.1.

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DDC Device A DDC Device B

SDA

SCL

GND

RpRp

SDA in

SDA out

SCL in

SDA out

SDA in

SDA out

SCL in

SDA out

C Interface Backgrounder

C.1 DDC Interface

Two wires, serial data (SDA) and serial clock (SCL), carry information between the devices connected to the bus. These lines are connected to all devices on the DDC. SCL is used to synchronize data transfers and SDA is the data line. Both SCL and SDA lines are “open drain” drivers. This means that DDC devices can only drive them low or leave them open. The pull-up resistor (Rp) pulls the line up to VDD if no DDC device is pulling it down to GND. If the pull-up resistors are missing, the SCL and SDA lines are undefined and the DDC bus will not work. For most DDC systems the low and high input voltage level thresholds of SDA and SCL depend on VDD. See the LEA-6 Data Sheet [1] or NEO-6 Data Sheet [3] for the applicable voltage levels.

Figure 66: A simple DDC connection

The signal shape and the maximum rate in which data can be transferred over SDA and SCL is limited by the values of Rp and the wire and I/O capacitance (Cp). Long wires and a large number of devices on the bus increase Cp, therefore DDC connections should always be as short as possible. The resistance of the pull-up resistors and the capacitance of the wires should be carefully chosen.

Figure 67: DDC block diagram

C.1.1 Addresses, roles and modes

Each device connected to a DDC is identified by a unique 7-bit address (e.g. whether it’s a microcontroller, EEPROM or D/A Converter, etc.) and can operate as either a transmitter or receiver, depending on the function

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Transmit

Receive Master: sends the clock and addresses slaves

Sends data to slave

Receives data from slave

Slave: receives the clock and address

Sends data to master

Receives data from master

of the device. The default DDC address for u-blox GPS receivers is set to 0x42. Setting the mode field in the CFG-PRT message for DDC accordingly can change this address.

The first byte sent is comprised of the address field and R/W bit. Hence the byte seen on the bus 0x42 is

shifted by 1 to the left plus R/W bit thus being 0x84 or 0x85 if analyzed by scope or protocol analyzer.

In addition to transmitters and receivers, devices can also be considered as masters or slaves when performing data transfers. A master is the device which initiates a data transfer on the bus and generates the clock signals to permit that transfer. At that time, any device addressed is considered a slave. The DDC-bus is a multi-master bus, i.e. multiple devices are capable of controlling the bus. Such architecture is not permanent and depends on the direction of data transfer at any given point in time. A master device not only allocates the time slots when slaves can respond but also enables and synchronizes designated slaves to physically access the bus by driving the clock. Although multiple nodes can assume the role of a master, only one at any time is permitted to do so. Thus, when one node acts as master, all other nodes act as slaves. Table 33 shows the possible roles and modes for devices connected to a DDC bus.

Table 33: Possible roles and modes of devices connected to DDC bus

u-blox 6 GPS receivers normally run in the slave mode. There is an exception when an external EEPROM is attached. In that case, the receiver attempts to establish presence of such a non-volatile memory component by writing and reading from a specific location. If EEPROM is present (assumed to be located at a fixed address 0xA0), the receiver assumes the role of a master on the bus and never changes role to slave until the following start-up (subject to EEPROM presence). This process takes place only once at the start-up, i.e. the receiver’s role cannot be changed during the normal operation afterward. This model is an exception and should not be

implemented if there are other participants on the bus contending for the bus control (µC / CPU, etc.). As a slave on the bus, the u-blox 6 GPS receiver cannot initiate the data transfers. The master node has the

exclusive right and responsibility to generate the data clock, therefore the slave nodes need not be configured to use the same baud rate. For the purpose of simplification, if not specified differently, SLAVE denotes the u-blox 6

GPS receiver while MASTER denotes the external device (CPU, μC) controlling the DDC bus by driving the SCL line.

u-blox GPS receivers support Standard-Mode I2C-bus specification with 7-bit addressing and a data

transfer rate up to 100 kBit/s and a SCL clock frequency up to 100 kHz.

C.1.2 DDC troubleshooting

Consider the following questions when implementing I2C in designs:

 Is there a stable supply voltage Vdd? Often, external I

provided with Vdd.

 Are appropriate termination resistances attached between SDA, SCL and Vdd? The voltage level on SDA and

SCL must be Vdd as long as the bus is idle and drop near GND if shorted to GND. [Note: Very few I2C masters exist which drive SCL high and low, i.e. the SCL line is not open-drain. In this case, a termination resistor is not needed and SCL cannot be pulled low. These masters will not work together with other masters (as they have no multi-master support) and may not be used with devices which stretch SCL during transfers.]

 Are SDA and SCL mixed up? This may accidentally happen e.g. when connecting I

connectors.

 Do all I  Do all I  If more than one I

C devices support the I2C supply voltage used on the bus?

C devices support the maximum SCL clock rate used on the bus?

C master is connected to the bus: do all masters provide multi-master support?

C devices (like I2C masters or monitors) must be

C buses with cables or

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SPI Slave

MISO

MOSI

SCK

SCS

 Are the high and low level voltages on SDA and SCL correct during I

C transfers? The I2C standard defines the low level threshold with 0.3 Vcc, the high level threshold with 0.7 Vcc. Modifying the termination resistance Rp, the serial resistors Rs or lowering the SCL clock rate could help here.

 Are there spikes or noise on SDA, SCL or even Vdd? They may result from interferences from other

components or because the capacitances Cp and/or Cc are too high. The effects can often be reduced by using shorter interconnections.

For more information about DDC implementation refer to the u-blox 6 Receiver Description including

Protocol Specification [4].

C.2 SPI Interface

C.2.1 SPI basics

Devices communicate in master/slave mode where the master device provides the clock signal (SCK) and determines the state of the chip select (SCS/SS_N) lines, i.e. it activates the slave it wants to communicate with. The slave device receives the clock and chip select from the master. Multiple slave devices are allowed with individual slave select (chip select) lines. This means that there is one master, while the number of slaves is only limited by the number of chip selects. In addition to reliability and relatively high speed (with respect to the conventional UART), the SPI interface is easy to use and requires no special handling or complex communication stack implementation in the software.

The standard configuration for a slave device (see Figure 68) uses two control and two data lines. These are identified as follows:

 SCS — Slave Chip Select (control: output from master, usually active low)  SCK — Serial Clock (control: output from master)  MOSI — Master Output, Slave Input (data: output from master)  MISO — Master Input, Slave Output (data: output from slave)

Alternative naming conventions are also widely used. Confirm the pin/signal naming with specific

components used.

Figure 68: SPI slave

SPI always follows the basic principle of a shift register. During an SPI transfer, command codes and data values are simultaneously transmitted (shifted out serially) and received (shifted in serially). The data is entered into a shift register and then internally available for parallel processing. The length of the shift registers is not fixed, but can vary from device to device. Normally the shift registers are 8Bit or integral multiples thereof. However, they can also have an odd number of bits. For example two cascaded 9Bit EEPROMs can store 18Bit data.

When an SPI transfer occurs, an 8-bit character is shifted out one data pin while a different 8-bit character is simultaneously shifted in a second data pin. Another way to view this transfer is that an 8-bit shift register in the master and another 8-bit shift register in the slave are connected as a circular 16-bit shift register. When a transfer occurs, this distributed shift register is shifted eight bit positions; thus, the characters in the master and slave are effectively exchanged.

The serial clock (SCK) line synchronizes shifting and sampling of the information on the two serial data lines (MOSI and MISO). The chip select (SCS/SS_N) line allows individual selection of a slave SPI device. If an SPI slave

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SPI Master

SPI Slave

Chip Select

MOSI

SCK

Data Input

MISO

SPI Slave

SCS

Clock

Data Output

MOSI

SS_N

SCK

MISO

device is not selected (i.e. its chip select is not activated), its data output enters a high-impedance state (hi-Z) and does not interfere with SPI bus activities.

The data output MISO functions as the data return signal from the slave to the master. Figure 69 shows a typical block diagram for an SPI master with several slaves. Here, the SCK and MOSI data lines

are shared by all of the slaves. Also the MISO data lines are linked together and led back to the master. Only the chip selects are separately brought to each SPI device.

Figure 69: Master with independent slaves

SPI allows multiple microcontrollers to be linked together. These can be configured according to single or multiple master protocols. In the first variant the microcontroller(s) designated as slave(s) behave like a normal peripheral device. The second variant allows for several masters and allows each microprocessor the possibility to take the role of master and to address another microprocessor. In this case one microcontroller must permanently provide the clock signal.

There are two SPI system errors. The first occurs if several SPI devices want to become master at the same time. The other is a collision error that occurs for example when SPI devices work with different polarities.

Systems involving multiple microcontrollers are beyond the scope of this document.

Cascading slave peripherals is not supported.

Four I/O pin signals are associated with SPI transfers: the SCK, the MISO data line, the MOSI data line, and the active low SCS/SS_N pin. In the unselected state the MISO lines are hi-Z and therefore inactive. The master decides with which peripheral device it wants to communicate. The clock line SCK provides synchronization for data communication and is brought to the device whether or not it is selected.

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The majority of SPI devices provide all four of these lines. Sometimes MOSI and MISO are multiplexed, or else one is missing. A peripheral device, which must not or cannot be configured, requires no input line but only a data output. As soon as it gets selected it starts sending data. In some ADCs therefore the MOSI line is missing. Some devices have no data output (e.g. LCD controllers which can be configured, but cannot send data or status messages).

The following rules should answer the most common questions concerning these signals:

 SCK: The SCK pin is an output when the SPI is configured as a master and an input when the SPI is

configured as a slave. When the SPI is configured as a master, the SCK signal is derived from the internal bus clock. When the master initiates a transfer, eight clock cycles are automatically generated on the SCK pin. When the SPI is configured as a slave, the SCK pin is an input, and the clock signal from the master synchronizes the data transfer between the master and slave devices. Slave devices ignore the SCK signal unless the slave select pin is active low. In both the master and slave SPI devices, data is shifted on one edge of the SCK signal and is sampled on the opposite edge where data is stable. Edge polarity is determined by the SPI transfer protocol.

 MISO/MOSI: The MISO and MOSI data pins are used for transmitting and receiving serial data. When the

SPI is configured as a master, MISO is the master data input line, and MOSI is the master data output line. When the SPI is configured as a slave, these pins reverse roles.

 SCS/SS_N: In master mode, the SCS output(s) select external slaves (e.g. SCS1_N, SCS2_N). In slave mode,

SS_N is the slave select input. The chip select pin behaves differently on master and slave devices. On a slave device, this pin is used to enable the SPI slave for a transfer. If the SS_N pin of a slave is inactive (high), the device ignores SCK clocks and keeps the MISO output pin in the high-impedance state. On a master device, the SCS pin can serve as a general-purpose output not affecting the SPI.

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Find a place with open sky view e.g. a big parking site

Start GPS and stand still for 90 seconds until valid position is calculated

Drive straight route for 500m, at least 40 km/h

Drive curves and straight segments for ca. 5 minutes with good visibility in any order

Exeed 60 km/h for at least 10 sec

Make at least two sharp left turns (90 deg or more)

Make at least two sharp right turns (90 deg or more)

Collect data of active temperature compensation

Phase I

Phase II

Phase III

Phase IV

Initial Calibration

Ongoing Fine

Calibration

D DR calibration

D.1 Constraints

The calibration of the DR sensors is a transparent and continuously ongoing process during periods of good GPS reception:

 Gyroscope Bias Voltage level of the gyroscope while driving a straight route or not

moving

 Gyroscope Scale Factor Adjusted while in left and right turns; gyro sensitivity  Speed Pulse Scale Factor Used to calibrate odometer pulse frequency to GPS speed over ground  Temperature Compensation The gyroscope is a temperature-dependent device that requires

temperature compensation

When a new GPS receiver is installed in a vehicle, the accuracy is only moderately good until sufficient calibration data has been collected, e.g. during a first drive. With time, continuous calibration results in continuous improvement of dead reckoning accuracy. Small discontinuities, like deviating wheel diameters after exchanging tires (summer vs. snow tires) or aging of the sensors, will be balanced out by ongoing automatic calibration.

Calibration parameters must be reset, if

 a DR module is transferred to a different vehicle and/or a different gyroscope is connected  the sensor integrity check has reported any failure from the sensors and set itself into GPS only mode

Calibration can be reset with UBX message UBX – CFG (Config) – EKF (Extended Kalman Filter).

D.2 Initial calibration drive

For optimum navigation performance the system needs some learning time and distance for calibrating the various sensors inputs. The following driving directions are recommended to achieve an efficient calibration so dead reckoning yields high accuracy after the shortest possible period of time.

Figure 70: Initial DR Calibration Drive

The mentioned distances and durations are typical values, a better indication is the sensor calibration status given in UBX – ESF (External Sensor Fusion) – STATUS (Status). The status values indicate which phase of the initial calibration the receiver is in (calibrating, coarse calibration, fine calibration). In Phase IV good DR

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performance can already be expected, as all sensors are calibrated. Still further fine calibration will be ongoing with good GPS reception and, if a temperature sensor is available, the temperature compensation table will be filled. Gyro offset values are measured as soon as the car stops for more than 3 seconds and are stored in the temperature compensation table to further increase the performance.

The above instructions result in a calibration status within the shortest period of time. Should traffic, road

and regulatory conditions not allow such a calibration drive, the time until optimum calibration will increase. However navigation results are already satisfactory after a relatively short driving distance and time.

The above instructions shall not be made a rule towards any end user. They shall only be

applied in a testing environment where sufficient care is taken that these driving instructions can be carried out without creating any risk of accidents or violation of regulations.

Consequences of a bad/wrong calibration procedure

u-blox SFDR Technology needs well-calibrated sensors to have optimal performance. A poorly calibrated system will report wrong positions and headings during GPS loss. Also the performance is degraded during good GPS performance, as the position output with good GPS performance will be combined with the poor data from the sensors.

As long as the miscalibration is minor (e.g. change of tires from summer to winter tires), the system will recover itself. If the miscalibration leads to a ‘sensor integrity check error’ (the receiver reports GPS only solutions), a reset of the calibration data and new initial calibration is required.

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Ublox NEO-6, MAX-6, LEA-6 Integration Manual

Specifications and Main Features

Frequently Asked Questions

User Manual