This document is available at HTTP://WWW.FALCOM.DE/ .
JP7-T Family
GPS-Receiver
Hardware description
Version 1.02
GPS-RECEIVER JP7-T VERSION 1.02
Contents
0 INTRODUCTION ..............................................................5
0.1 GENERAL........................................................................................................................................ 5
0.2 SCOPE OF THE USER’S MANUAL ...................................................................................................... 6
0.3 USED ABBREVIATIONS.................................................................................................................... 7
0.4 RELATED DOCUMENTS.................................................................................................................... 7
0.5 ORDER OPTIONS.............................................................................................................................. 8
1 SECURITY .........................................................................9
1.1 GENERAL INFORMATION................................................................................................................. 9
1.2 RESTRICTED USE............................................................................................................................. 9
1.3 CHILDREN ...................................................................................................................................... 9
1.4 OPERATION/ANTENNA .................................................................................................................... 9
1.5 ELECTROSTATIC DISCHARGE (ESD)............................................................................................. 10
2 SAFETY STANDARDS ...................................................11
3 GPS BASICS PRINCIPLE ..............................................12
3.1 SIGNAL PROCESSING OPERATION ................................................................................................. 12
4 TECHNICAL DATA........................................................13
5 DESCRIPTION OF OPERATING MODES .................15
5.1 NORMAL OPERATION ................................................................................................................... 15
5.2 TRICKLE POWER OPERATION ....................................................................................................... 15
5.3 PUSH-TO-FIX MODE ..................................................................................................................... 16
5.4 NMEA INPUT MESSAGE FOR TRICKLE POWER MODE................................................................... 16
6 TECHNICAL DESCRIPTION .......................................19
6.1 RECEIVER ARCHITECTURE ........................................................................................................... 19
6.2 DESCRIPTION OF GPS RECEIVING SIGNALS................................................................................... 20
6.3 START-UP MODES ........................................................................................................................ 20
6.3.1 Cold start...................................................................................................................................... 20
6.3.2 Warm start ................................................................................................................................... 21
6.3.3 Hot start ....................................................................................................................................... 21
6.4 PRODUCT APPLICATIONS .............................................................................................................. 21
6.5 TECHNICAL SPECIFICATIONS......................................................................................................... 22
6.5.1 Electrical Characteristics ............................................................................................................. 22
6.6 HARDWARE INTERFACE ................................................................................................................ 24
6.7 BALLS ASSIGNMENT OF THE JP7-TB............................................................................................. 25
6.8 PIN ASSIGNMENT OF THE 50-PIN CONNECTOR ............................................................................... 28
6.8.1 Configuration and timing signals................................................................................................. 30
6.8.2 Serial communication signals ...................................................................................................... 31
6.8.3 DC input signals .......................................................................................................................... 32
6.8.4 General purpose input/output....................................................................................................... 33
7 SOFTWARE INTERFACE.............................................34
7.1 SIRF BINARY DATA MESSAGE....................................................................................................... 34
7.2 NMEA DATA MESSAGE ................................................................................................................ 36
7.2.1 NMEA output messages .............................................................................................................. 37
7.2.2 NMEA input messages ................................................................................................................ 37
7.2.3 Transport Message....................................................................................................................... 38
8 MECHANICAL DRAW .................................................. 39
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GPS-RECEIVER JP7-T VERSION 1.02
9 LAYOUT RECOMMENDATION..................................42
9.1 GROUND PLANES .......................................................................................................................... 42
9.2 RF CONNECTION........................................................................................................................... 42
10 FIRST STEPS TO MAKE IT WORK............................45
11 APPENDIX .......................................................................48
11.1 BOARD-TO-BOARD CONNECTOR ................................................................................................... 48
11.2 RF CONNECTOR............................................................................................................................ 48
11.3 FIRMWARE INTERFACE ................................................................................................................. 49
11.4 XTRAC FIRMWARE DESCRIPTION .................................................................................................. 49
11.4.1 SiRFXTrac2 firmware default settings........................................................................................ 49
11.4.2 Order options ............................................................................................................................... 50
Version history
Version number Author Changes
1.00 Fadil Beqiri Initial version
1.01 Fadil Beqiri - The signal names of serial ports updated
- New section 11.4 “XTrac software
description” added.
- CheckSum calculation added
- A complete update implemented.
1.02 Fadil Beqiri - Chapter 11.3 updated.
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GPS-RECEIVER JP7-T VERSION 1.02
Cautions
Information furnished herein by FALCOM is believed to be accurate
and reliable. However, no responsibility is assumed for its use. Also
the information contained herein is subject to change without notice.
Please, read carefully the safety precautions.
If you have any technical questions regarding this document or the
product described in it, please contact your vendor.
General information about FALCOM and its range of products is
available at the following internet address: http://www.falcom.de/
Trademarks
Some mentioned products are registered trademarks of their respective
companies.
Copyright
The JP7-T family hardware description and user’s guide are
copyrighted by FALCOM GmbH with all rights reserved. No part of
this user’s guide may be produced in any form without the prior
written permission of FALCOM GmbH.
FALCOM GmbH.
No patent liability is assumed with respect to the use of the information
contained herein.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
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GPS-RECEIVER JP7-T VERSION 1.02
0 Introduction
0.1 General
This description is focussed on the GPS receiver of the FALCOM JP7-T
family from FALCOM GmbH. The JP7-T family is an excellent device
designed and supports a wide variety of solutions regarding to the customer
fulfilment, the wide variety of the JP7-T family offers easy integration in the
various way on the user independent application platform. Regarding to the
JP7-T family (which contains JP7-T, JP7-TB, JP7-TC-1(-2)) concept, there
are three different GPS receiver with different options. This manual contains
information about purpose and use of the GPS receivers included into the
FALCOM JP7-T family. Please read this manual very carefully to avoid any
mistakes and to secure an optimal use of the devices. Each GPS receiver
into the JP7-T family is a single-board 12 parallel channel receiver intended
as a component for OEM products. The FALCOM JP7-T family is based
and advanced on the Falcom JP7 GPS receiver which delivers major
advancement in GPS performance, accuracy, integration, computing power
and flexibility without modification regarding to the receiver form factor
and pin-out. Each GPS receiver of the FALCOM JP7-T family has an
integrated temperature compensated crystal oscillators (TCXO). Due to the
higher stability of frequency it offers a high improved performance.
Additionally, a TCXO accept the condition for use the SiRFXTrac2
firmware. The JP7- T family using SiRFXTrac2 firmware is able to track
the GPS signals an extremely small level by 16 dBHz. In addition, higher
sensitivity allows it more flexibility on the its design, the placement of the
antenna and the selection of the kind of antenna. The GPS receiver
continuously tracks all satellites in view, thus providing accurate satellite
position data. The highly integrated digital receiver uses the SiRFstarII-Low
Power chipset. The internal GPS software completes the package providing
flexible system architecture for standalone GPS based products.
In order to save space on the application platform, the Falcom JP7-T family
comes as an extremely slim and compact module. This makes it ideally
suited for a broad range of mobile computing devices, and particularly
offers easy integration with smart phones, PDAs, and other handhelds.
The FALCOM JP7-T family is also designed to be an entire product such as
an AVL tracking unit, handheld GPS.
Please consult SiRF (www.sirf.com
SiRFstarII-Low Power chipset.
) for special information about the
Figure 1: The FALCOM JP7-T family GPS receiver (top, side and bottom view)
Users are advised to proceed quickly to the chapter "Security" and read the
hints carefully to secure its optimal use.
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GPS-RECEIVER JP7-T VERSION 1.02
0.2 Scope of the user’s manual
This document describes the hardware interface and the technical
specifications of the JP7-T.
It is also the preliminary data sheet for the electrical and mechanical device
application design.
As far as JP7-T family concept is concerned, there are three different JP7-T
GPS Receiver Modules available. The difference between these receivers
can be recognised by looking on the bottom side of the module (see attached
picture on the chapter 0.5 “Order option”).
To choose a unit it depends on the customer requirements:
JP7-T JP7-TB JP7-TC-1 JP7-TC-2
RF Part
TCXO 25.5535 MHz 25.5535 MHz 25.5535 MHz 25.5535 MHz
Active
antenna power
built in built in built in built in
control
RF connector Not available Not available
Digital Part
Connector Not available Not available
Balls Not available
48-Balls are
available
U.FL-R-SMT –
plug antenna
connector from
Hirose.
50-pin, Hirose
DF12C, Board-To-
Board connector
Not available Not available
No RF
connector.
Solder pads, only
50-pin, Hirose
DF12C, Board-
To-Board
connector
In this manual user will not find separately description for each option of
devices. The interfaces, pin-out and some application’s example are the
same for all devices.
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GPS-RECEIVER JP7-T VERSION 1.02
0.3 Used abbreviations
Abbreviation Description
DGPS Differential GPS
DOP Dilution of Precision
GPS Global Positioning System
GGA GPS Fixed Data
LNA Low Noise Amplifier
NMEA National Maritime Electronics Association
PRN Pseudo - Random Noise Number – The Identity of GPS satellites
RF Radio Frequency
RP Receive Protocol
RTC Real Time Clock
RTCM Radio Technical Commission for Maritime Services
SDI Data input
SDO Data output
SA Selective Availability
WAAS Wide Area Augmentation System
MSK Minimum Shift Keying
PCB Printed Circuit Board
PRN Pseudo-random noise
IF Intermediate Frequency
A/D Analog/Digital
0.4 Related documents
[1.] SiRF binary and NMEA protocol specification;
http://www.falcom.de/service/downloads/manual/SiRF/SiRFmessages.pdf
[2.] SiRF-demo software and manual;
http://www.falcom.de/service/downloads/manual/SiRF/SiRFdemo.pdf
http://www.falcom.de/service/downloads/manual/SiRF/SiRFdemo.zip
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GPS-RECEIVER JP7-T VERSION 1.02
0.5 Order options
Before you start up the receiver, make sure that your package includes the
following items. If any item is missing or damaged, please contact your
vendor immediately. According to your requirements you can choose the
desired unit. In the figure below the available components are marked with
red colour. (In order to have a clearly view and to detect the required option
of JP7-T family imaged below, please print this page with a colour printer.)
The table below contains the order options of JP7-T family.
Name Options
JP7-T 30-pin out on the left and right side of JP7-T are available for use
JP7-TB 48 Balls are available for use
JP7-TC-1
JP7-TC
JP7-TC-2
A 50-pin connector and a RF connector are
available for use
A 50-pin connector and solder pads for an antenna
cable are available for use.
There is no antenna cable included in the delivery
package.
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GPS-RECEIVER JP7-T VERSION 1.02
1 Security
This chapter contains important information for the safe and reliable use of
the GPS receiver. Please read this chapter carefully before starting to use the
GPS receiver.
1.1 General information
The Global Positioning System uses satellite navigation, an entirely new
concept in navigation. GPS has become established in many areas, for
example, in civil aviation or deep-sea shipping. It is making deep inroads in
vehicle manufacturing and before long everyone of us will use it this way or
another.
The GPS system is operated by the government of the United States of
America, which also has sole responsibility for the accuracy and
maintenance of the system. The system is constantly being improved and
may entail modifications effecting the accuracy and performance of the GPS
equipment.
1.2 Restricted use
Certain restrictions on the use of the GPS receiver may have to be observed
on board a plane, in hospitals, public places or government institutions,
laboratories etc. Follow these instructions.
1.3 Children
Do not allow children to play with the GPS receiver. It is not a toy and
children could hurt themselves or others. The GPS receiver consists of many
small parts which can come loose and could be swallowed by small
children. Thoughtless handling can damage the GPS receiver.
1.4 Operation/antenna
Operate the GPS receiver with an antenna connected to it and with no
obstruction between the receiver and the satellite.
Make absolutely sure that the antenna socket or antenna cable is not shorted
as this would render the GPS receiver disfunctional.
Do not use the receiver with a damaged antenna. Replace a damaged
antenna without delay. Use only a manufacturer-approved antenna. Use only
the supplied or an approved antenna with your GPS receiver. Antennas from
other manufacturers which are not authorized by the supplier can damage
the GPS receiver.
Technical modifications and additions may contravene local radiofrequency emission regulations or invalidate the type approval.
Authorized GPS antennas:
FAL-ANT-3 (active antenna)
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GPS-RECEIVER JP7-T VERSION 1.02
1.5 Electrostatic Discharge (ESD)
The JP7-T family GPS receiver contains class 1 devices. The following
Electrostatic Discharge (ESD) precautions are recommended:
- Protective outer garments.
- Handle device in ESD safeguarded work area.
- Transport device in ESD shielded containers.
- Monitor and test all ESD protection equipment.
- Treat the JP7-T family GPS receiver as extremely sensitive to ESD.
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GPS-RECEIVER JP7-T VERSION 1.02
2 Safety standards
The GPS receiver meets the safety standards for RF receivers and the
standards and recommendations for the protection of public exposure to RF
electromagnetic energy established by government bodies and professional
organizations, such as directives of the European Community, Directorate
General V in matters of radio frequency electromagnetic energy.
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GPS-RECEIVER JP7-T VERSION 1.02
3 GPS basics principle
3.1 Signal Processing Operation
The JP7-T family is designed to use L1 Frequency (C/A Code). The module
is separated into four major parts: RF frequency down-converter, digital
baseband demodulation, embedded ARM microprocessor and internal
GPS software stored on-board (8 MBits) Flash-Memory. The RF frequency
conversion and the baseband demodulation are executed by hardware while
the embedded ARM processor computes the GPS Position, Velocity and
Time solution employing the internal GPS software.
♦ The purpose of the RF circuitry is to reinforce the very weak (-
130dBm nominal) GPS signal, filters it and down-converts it to an
Intermediate Frequency (IF) of 9.45MHz for digital processing. The
JP7-T family architecture relies on the high level of integration in the
RF part to significantly reduce part count and circuit complexity. The
IF filter is built-in as well.
♦ The digital baseband demodulator takes the quantified GPS signal and
detects the individual satellites serial data bit stream, along with the
associated pseudo range. This action consists of removing spread
spectrum and Doppler frequency components of the signal to obtain
the serial data messages.
♦ The embedded ARM processor monitors channel allocation, extracts
the raw satellite tracking data, computes the position and time solution
and sends it on a serial port for high level applications to use or
process it locally. Support functions for the microprocessor include
real-time clock and reset pulse generator circuits.
♦ The internal GPS software monitors and allocate channels, computes
the Position, Velocity and Time using the pseudo-range of the
satellites and reformat the data to be output at the serial interface or
used locally. The internal GPS software is a tasking based architecture
driven by the 100ms interrupt generated by GSP2e internal hardware.
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GPS-RECEIVER JP7-T VERSION 1.02
4 Technical data
FEATURES
- OEM single board 12 channel GPS receiver
- size: JP7-T : 25,4 x 25,4 x 3 mm (L x B x H)
JP7-TB : 25,4 x 25,4 x 3.3 mm (L x B x H)
JP7-TC-1 : 25,4 x 25,4 x 5.2 mm (L x B x H)
JP7-TC-2 : 25,4 x 25,4 x 5.2 mm (L x B x H)
- weight: JP7-T : 2,5 g (without shielding)
JP7-TB : 2,5 g (without shielding)
JP7-TC-1 : 2,5 g (without shielding)
JP7-TC-2 : 2,5 g (without shielding)
- Casing: Fully shielded
- TCXO
- 8Mbit FLASH memory
- operating voltage: +3.3 V DC ±5 %
- power consumption: 220 mW (continuous mode with Low
Power chipset)
- temperature range: -40 to +85 °C (operation, transportation
and storage)
- protocol: SDI1/ SDO1:
NMEA 9600 baud, Msg.: GLL, GGA,
RMC,
VTG, GSV, GSA
8 data bits, no parity, 1 stop bit
SDI2/ SDO2:
RTCM, 9600 baud
- trickle power mode: The default Mode of FALCOM JP7-T is
continuous Mode, but the user can set
FALCOM JP7-T into the Trickle Power
Mode via input command message. The
FALCOM JP7-T family enters the trickle
power mode corresponding to figure 2 (
ms OFF Time and 200 ms ON Time
valid GPS data are available. As a result the
average power consumption is reduced by
approximately 80 % (approximately 150
mW). The settings for the trickle power
mode can be modified by using the SiRFstar
demo software. For example if the FALCOM
JP7-T is configured to enter the OnTime
mode each 10 s for a duration of 200 ms the
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) as soon as
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GPS-RECEIVER JP7-T VERSION 1.02
average power consumption can be reduced
up to approx. 95 % (approx. 15 mW, ca. 4,8
mA at Vcc=3.3 V).
For more details see chapter 4 “Operating
modes”.
Figure 2: Example for the trickle power mode of FALCOM JP7-T family
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GPS-RECEIVER JP7-T VERSION 1.02
5 Description of operating modes
There are three basic operating in which the JP7-T family operates during
use. Each mode is used to accomplish a different task during the process of
acquiring and maintaining the GPS information. The Falcom JP7-T family
designs include all the functionality necessary to implement the three
different modes of operation. The default mode of JP7-T family is normal
mode (continuous mode). Three different operating modes are described
below. Additionally, two of them are designed as low-power mode
consumption such as the Trickle Power mode and Push-To-Fix mode.
5.1 Normal Operation
In this default implementation of normal mode the JP7-T family is fully
powered and performs the function of signal search, acquisition,
measurement and satellite tracking. The amount of time spent in the initial
full power is dependent on the start condition that applies the number of
satellites for which the ephemeris must be collected and the time to calibrate
the RTC as well as the location of the GPS antenna (which it must have an
unobstructed view to the sky in order to receive the satellite radio
transmissions). When the JP7-T family has been locked-on to at least four
satellites, the receiver is able to calculate its current positions. In this mode
the JP7-T family is fully powered and satellite searching, initial acquisition,
initial position calculation and tracking measurements functions are always
performed. In order to reduce the start up time of the receiver it is preferable
to be connected to an external back up battery, so that the RTC is running
during the power interrupt. The backup power is required for retention of
SRAM memory and maintaining the Real-Time-Clock. The validity of data
stored in SRAM is kept due to RTC keeps running and these data will be
needed on the next power up scenario.
5.2 Trickle Power Operation
In the Trickle Power mode, power is still applied to the JP7-T family, but
the GPS engine is shut off and RF circuits are powered down. The Trickle
Power mode provides a method of operating the JP7-T family in a user
programmable duty cycle, consisting of a receiver measurement on time
tracking and an interval of position update, thereby reducing the average
power consumption over a period of time. The transition into the Trickle
Power mode of JP7-T family can be implemented and configured by using
the Set Operating Mode command in SiRFdemo. Between two on time
tracking periods the JP7-T family sets itself in the sleep phase in other word
into the low power consumption. The transition from sleep mode of JP7-T
family back to the on time tracking is generated through the internal RTC
which transmits a wakeup signal to the GPS engine to switch it on as well
the RF circuit is powered on. The JP7-T is waked up and begins to acquire
the on view satellites. In order to reduce the start up time of the receiver for
the next power up is preferable to connect an external back up battery, so
that the RTC is running during the power interrupt and the required data and
the Trickle Mode configuration are kept from previous operation. If the
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GPS-RECEIVER JP7-T VERSION 1.02
receiver fails to acquire satellites within a given period of time (approx. 150
sec), the receiver sets itself into the sleep phase. The duration of this sleep
phase is approx. 30 sec. After that, the receiver wakes up, reset itself and
tries to acquire satellites which are in view. This procedure repeats itself
until the initial position computation of GPS receiver is completed.
Hint:
After initial turn on or system reset, the JP7-T will remain in the
full power tracking until a series of Kalman filter navigation
solution is obtained, all ephemeris data is collected and the RTC is
calibrated prior to transitioning to the low power duty cycle mode.
5.3 Push-to-Fix Mode
The Push-to-Fix mode puts the FALCOM JP7-T family into a background
duty cycle which provides a periodic refresh of position, receiver time,
ephemeris data and RTC calibration every 30 minutes. The Push-to-Fix
mode is similar but executive from Trickle Power mode, meaning that only
one mode can be set at a time. In this mode the receiver sets itself into the
sleep phase for 29.5 minutes and a full tracking phase for 30 seconds.
During the tracking phase the JP7-T family acquires satellites, computes
position and updates ephemeris data as well the RTC is being calibrated.
The transition into the Push-to-Fix mode of JP7-T family can be
implemented and configured by using the Set Operating Mode command
in SiRFdemo. During the subsequent background cycles or when a user
requests a position update (the RESET_N has to be used) a reset is
generated and a hot start will be typically performed which may take up to a
maximum of 8 seconds. The receiver wakes up, computes its position fix
and goes back to the previous sleep phase again.
5.4 NMEA input message for Trickle Power Mode
The input command message below sets the FALCOM JP7-T family into
the Trickle Power Mode or Push-To-Fix Mode. Details to configure Trickle
Power Mode and Push-To-Fix Modes are described below.
The receiver accepts the input message with following format:
$PSRF107,<parameter>, <parameter> ,<parameter><* Checksum><CR> <LF>.
COMAND
SYNTAX
$PSRF107,
ptf,
dc,
msot
*XX
<CR><LF>
Parameters description:
ptf // numeric, performs the receiver in one of two pre-defined modes
Possible values:
0: Set the receiver in Trickle Power mode
1: Set the receiver in Push-To-Fix mode
dc // numeric, Duty Cycle in percent (%)
Possible value:
max 1000: Set the time which will be spent for tracking (dc% / 10)
msot // numeric, the on Time in milliseconds
Possible value
200.. 900: Set the time duration of each tracking period
*XX // Checksum has to be calculated in hexadecimal.
DESCRIPTION
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GPS-RECEIVER JP7-T VERSION 1.02
Example:
$PSRF107,0,200,200*3D
The receiver will be set in Trickle Power mode where 20% of time it will spend for
tracking and the tracking period will takes 200 msec.
Table 1: Example of Trickle Power Mode Control.
Note:
If the receiver is set into the Trickle Power Mode, the high data rate
transmission is recommend as suitable.
Computation of Duty Cycle and On Time
The Duty Cycle is the desired time, which will be spent for tracking. The
On Time is the duration of each tracking period (range is 200 - 900 msec.)
To calculate the Trickle Power update rate as a function of Duty Cycle and
On Time, use the following formula:
On Time – (Duty Cycle * On Time)
Off Time = -------------------------------------------- Duty Cycle
Update rate = Off Time + On Time
Hint:
It is not possible to enter an On Time > 900 msec.
Following are some examples of selections:
Mode On Time (msec) Duty Cycle (%) Update Rate (1/Hz)
Continuous 1000 100 1
Trickle Power 200 20 1
Trickle Power 200 10 2
Trickle Power 300 10 3
Trickle Power 500 5 10
Table 2: Example of Selections for Trickle Power Mode of Operation.
On Time
(msec)
200
300
400
500
600
700
800
900
1 2 3 4 5 6 7 8 9 10
√ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √
Table 3: Trickle Power supported Modes.
Update Rates (seconds)
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GPS-RECEIVER JP7-T VERSION 1.02
Push-To-Fix
In this mode the receiver will turn on every 30 minutes to perform a system
update consisting of a RTC calibration and satellite ephemeris data
collection if required (i.e., a new satellite has become visible) as well as all
software tasks to support SnapStart in the event of an NMEA. Ephemeris
collection time in general takes 18 to 30 seconds If ephemeris data is not
required then the system will re-calibrate and shut down. In either case, the
amount of time the receiver remains off will be in proportion to how long it
stayed on:
On Period * (1-Duty Cycle)
Off period = -------------------------------------------- Duty Cycle
The off period has a possible range between 10 and 7200 seconds. The
default is 1800 seconds.
Comparison
A comparison of the Trickle Power and Push-to-Fix modes is shown in
Figure below. This diagram shows that for position update intervals less
than approximately 600 seconds (i.e. rates faster than one fix per 10
minutes), the Trickle Power mode at an update interval of 10 seconds offers
a lower power solution. The user would then be required to filter the output
position data to use only the data points corresponding to the desired update
interval. For example, if the desired position output is at 60 second intervals,
then the user would only need one out of every six position outputs at a 10
second Trickle Power update interval. Alternatively, the user could perform
smoothing or averaging of the position data and provide an output at the
desired rate.
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GPS-RECEIVER JP7-T VERSION 1.02
6 Technical Description
6.1 Receiver Architecture
The JP7-T family OEM GPS receiver from FALCOM is new OEM GPS
receiver product that features the SiRFstarII-Low Power chipset. This
completes 12 channel, WAAS-enabled GPS receiver provides a vastly
superior position accuracy performance in a much smaller package. The
SiRFstarII architecture builds on the high-performance SiRFstarI core,
adding an acquisition accelerator, differential GPS processor, multipath
mitigation hardware and satellite-tracking engine. The JP7-T family delivers
major advancements in GPS performance, accuracy, integration, computing
power and flexibility.
Figure 3: Receiver architecture of the JP7-T family GPS receiver.
Figure 3 above shows the block diagram of the JP7-T family architecture.
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GPS-RECEIVER JP7-T VERSION 1.02
6.2 Description of GPS receiving signals
When the GPS receiver is initially turned on, it begins to determinate its
current positions, velocity and time. In order to perform a successful start it
must have a current almanac, a reasonable expectation of its current location
and a reasonable idea of the current time. When the Ephemeris data are
completely collected, then satellite signals are tracked continuously and the
position is calculated from time to time.
While the receiver trying to obtain a position fix, it needs to be locked-on to
at least four satellites. In order to calculate quickly its current location, the
receiver uses the current received signals, together with data from its
memory (SRAM).
The initial state of the receiver refers to the last status of the receiver in
memory (SRAM). This essentially determines the length of time it will take
for the receiver to obtain a GPS fix. Position can be quickly fixed within 8
seconds from a "hot-start" state, and typically 45 seconds from a "cold-start"
state.
The receiver uses the satellite signals to calculate its exact current location
by calculating the receiver distance from the satellites. The position data
within the receiver is then converted into latitude and longitude coordinates,
which are usually provided in the geodetic datum on which the GPS is based
(WGS84).
6.3 Start-Up Modes
The start-up modes of the JP7-T family depend on the last stored position in
the SRAM memory, such as the current time and ephemeris data. So that the
JP7-T family can be initiated to one of three different start up procedures,
but note that only one can be initiated at a time. In order to perform a Warm
and Hot start, a backup battery has to be connected to the JP7-T family.
Without an external backup battery the receiver will perform a cold start
after every turn on. To achieve the faster start-up offered by a hot or warm
start, a backup battery must be connected. To maximize battery lifetime, the
battery voltage should not exceed the maximal supply voltage and should be
between 2.85 V and 3.15 V.
6.3.1 Cold start
The unit stores data about where the satellites are located at any given time.
The data is called almanac. Occasionally, when the JP7-T family has been
turned off for a long time, the almanac can get out-dated or “cold”. The cold
start takes place when the receiver does not know its last position or time. In
this start-up mode, the receiver either does not operate under back-up power
conditions or it is the first start-up time (i.e. no idea about ephemeris or
almanac data). At this time, the Ephemeris data has yet to be completely
collected. Once the ephemeris data is collected from in view satellites, then
the data from these satellites is considered valid and available for
navigation. This start up scenario is one of the longest time which the
receiver will take to obtain a GPS fix.
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GPS-RECEIVER JP7-T VERSION 1.02
6.3.2 Warm start
This start-up procedure so called Warm start is performed when the time
and position are known to within some limits, as well the almanac data are
known and at least 3 Satellites Ephemeris are valid from previous operation.
The validity of this data is dedicated if the receiver is switched off for more
than 2 hours. If the receiver has been moved for more than 100 miles or the
accurate time is currently not available then the Ephemeris data can be
invalid. In such case the receiver will have to acquire the satellites and to
collect the Ephemeris data which are in this scenario required.
6.3.3 Hot start
This start-up procedure so called Hot start is performed when the time and
position are accurate known, as well the almanac data are also valid. The
validity of this data is dedicated if the receiver has been switched off for less
than 2 hours and the real-time clock (RTC) has been operating during that
switch off time. This start-up procedure performs computing of valid
positions, only.
The problems which may be met while start-up modes:
The validity of the Real-time Clock (RTC) during start-up is determined in
part through a checksum of the SRAM to see if it has been corrupted. If the
SRAM checksum shows the memory has been corrupted, the RTC is also
assumed to be invalid and the system ignores the RTC value. In this case,
the system will not perform a hot start, but will fall back to a cold start mode
with a longer time to first fix (TTFF), on the order of less than 45 seconds
typical. These problems may happens in case of the RTC randomly drop
counts under minimal supply voltage conditions which is supplied from
external connected backup battery and supports the RTC operation (+3.0
VDC –5%).
6.4 Product applications
- Handheld GPS receiver applications
- Automotive applications
- Marine navigation applications
- Aviation applications
- Timing applications
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GPS-RECEIVER JP7-T VERSION 1.02
6.5 Technical specifications
6.5.1 Electrical Characteristics
6.5.1.1 General
Frequency L1, 1575.42 MHz
C/A code 1.023 MHz chip rate
Channels 12
6.5.1.2 Accuracy
Position 10 meters CEP without SA
Velocity 0.1 meters/second, without SA
Time 1 microsecond synchronized to GPS
time
6.5.1.3 DGPS Accuracy
Position 1 to 5 meters, typical
Velocity 0.05 meters/second, typical
6.5.1.4 Datum
WGS-84
6.5.1.5 Time to First Position*
Hot start < 4 sec., average
Warm start < 35 sec., average
Cold start < 45 sec., average
*
The values listed above are available by using the SiRFXTrac2 firmware, only.
6.5.1.6 Sensitivity *
Tracking 16 dBHz
Hot Start 23 dBHz
Warm Start 28 dBHz
Cold Start 32 dBHz
*
The sensitivity value is specified at the correlator. On a JP7-T Evaluation Receiver
using SiRFXTrac2 firmware with the supplied antenna, 32 dBHz is equivalent to 142 dBm or -172 dBW. Other board and antenna characteristics will vary.
6.5.1.7 Acquisition Rate
Snap start < 3 sec., average
Hot start < 8 sec., average
Warm start < 38 sec., average
Cold start < 45 sec., average
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GPS-RECEIVER JP7-T VERSION 1.02
6.5.1.8 Dynamic Conditions
Altitude 18,000 meters (60,000 feet) max.
Velocity <515 meters/second (1000 knots) max.
Acceleration 4 g, max.
Jerk 20 meters/second³, max.
6.5.1.9 DC Power
Main power + 3.3 V DC ±5 %
Continuous mode 65 mA at 3.3 V DC
Backup battery power +3 V DC ±5%
6.5.1.10 Serial Port
Electrical interface Two full duplex serial communication,
CMOS.
Protocol messages SiRF binary and NMEA-0183, version 2.32
with a baud rate selection
SiRF binary – position, velocity, altitude,
status and control NMEA – GGA, GLL,
GSA, GSV, RMC and VTG
DGPS protocol RTCM SC-104, version 2.32, type 1, 5 and
9
6.5.1.11 Time – 1PPS Pulse
Level CMOS
Pulse duration 100 ms
Time reference At the pulse positive edge
Measurements Aligned to GPS second, ± microsecond
6.5.1.12 TCXO-Specification
Typical phase noise density 1 Hz offset -57.0 dBc/Hz
Typical phase noise density 10 Hz offset -88.0 dBc/Hz
Typical phase noise density 100 Hz offset -112.0 dBc/Hz
Typical phase noise density 1 kHz offset -130.0 dBc/Hz
Typical phase noise density 10 kHz offset -140.0 dBc/Hz
Load sensitivity ± 10% load change 0.2 ± ppm
Long term stability Frequency drift over 1 year 0.5 to 2.0 ± ppm
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GPS-RECEIVER JP7-T VERSION 1.02
6.6 Hardware interface
Pin Name I/O Description Level
1 VCC I Supply voltage 3.3 V DC±5 %
2 GND Digital ground
3 BOOT_SELECT I Boots in update mode, if high CMOS
4 SDI1 I Serial Data Input A CMOS
5 SDO1 O Serial Data Output A CMOS
6 SDO2 O Serial Data Output B CMOS
7 SDI2 I Serial Data Input B CMOS
8 GPIO3 I/O See chapter 6.8.4
9 RF_ON O High if RF part on RF chip is on CMOS
10 GND Digital ground
11 RF_GND Analog ground
12 RF_GND Analog ground
13 RF_GND Analog ground
14 RF_GND Analog ground
15 RF_GND Analog ground
16 RF_GND Analog ground
17 RF_IN I GPS signal from connected
antenna
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
50 Ohms @
1.575 GHz
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GPS-RECEIVER JP7-T VERSION 1.02
Pin Name I/O Description Level
18 RF_GND Analog ground
19 V_ANT I Power supply for active antenna upto +12 V DC
20 VC3.0 O Supply voltage of RF section +3.0 V DC
21 V_BAT I Power for RTC and SRAM +3 V DC ±5%
22 RESET_N I Resets the unit if active LOW CMOS
23 GPIO10 I/O See chapter 6.8.4 CMOS
24 GPIO6 I/O See chapter 6.8.4 CMOS
25 GPIO5 I/O See chapter 6.8.4 CMOS
26 GPIO7 I/O See chapter 6.8.4 CMOS
27 GPIO0 I/O See chapter 6.8.4 CMOS
28 GPIO1 I/O See chapter 6.8.4 CMOS
29 T-MARK O One pulse per second CMOS
30 GND Digital ground
Table 4: Pin assignment of the JP7-T
6.7 Balls assignment of the JP7-TB
Figure 4: Balls assignment of the JP7-TB
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Th
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GPS-RECEIVER JP7-T VERSION 1.02
Ball Name I/O Description Level
1 GPIO1 I/O See chapter 6.8.4 CMOS
2 GPIO0 I/O See chapter 6.8.4 CMOS
3 GPIO7 I/O See chapter 6.8.4 CMOS
4 GPIO5 I/O See chapter 6.8.4 CMOS
5 GPIO6 I/O See chapter 6.8.4 CMOS
6 GPIO10 I/O See chapter 6.8.4 CMOS
7 RESET_N I Reset the unit, if Active Low CMOS
8 V_BAT I Power for RTC and SRAM +3 V DC ±5%
9 VC3.0 O Supply voltage of RF section
10 V_ANT I Power supply for an active
antenna
+ 3.0 V DC /
max. 25 mA
Up to +12 V DC /
max. 25 mA
11 RF_GND Analog ground
12 RF_GND Analog ground
13 RF_IN I GPS signal from connected
antenna
50 Ohms @ 1.575
GHz
14 GND Digital ground
15 GND Digital ground
16 GND Digital ground
17 GND Digital ground
18 GND Digital ground
19 GND Digital ground
20 GND Digital ground
21 GND Digital ground
22 GND Digital ground
23 GND Digital ground
24 GND Digital ground
25 GND Digital ground
26 GND Digital ground
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GPS-RECEIVER JP7-T VERSION 1.02
Ball Name I/O Description Level
27 GND Digital ground
28 GND Digital ground
29 GND Digital ground
30 GND Digital ground
31 Vcca O
Control output for RF part
+ 2.85 V DC /
max. 25 mA
32 GPIO3 I/O See chapter 6.8.4 CMOS
33 SDI2 I Serial Data Input B CMOS
34 SDO2 O Serial Data Output B CMOS
35 SDO1 O Serial Data Output A CMOS
36 SDI1 I Serial Data Input A CMOS
37 BOOT_SELECT I Boots in update mode, if high CMOS
38 GND Digital ground
39 VCC I Main power supply + 3.3 V DC ±5 %
30 VCC I Main power supply + 3.3 V DC ±5 %
41 GND Digital ground
42 RFPC1 O Control output for Trickle-
Power Mode
+ 2.85 V DC /
max. 25 mA
43 RFPC0 O
Control output for Trickle-
Power Mode
+ 2.85 V DC /
max. 25 mA
44 GPIO15 I/O See chapter 6.8.4 CMOS
45 GPIO14 I/O See chapter 6.8.4 CMOS
46 GPIO13 I/O See chapter 6.8.4 CMOS
47 T-MARK O 1 PPS Time Mark Output CMOS
48 GND Digital ground
Table 5: Pin assignment of the JP7-TB
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GPS-RECEIVER JP7-T VERSION 1.02
6.8 Pin assignment of the 50-pin connector
Figure 5: Pin out of the interface connector on the JP7-TC-1(-2)
Please note that, the JP7-TC-2 is without RF connector, and there is no
antenna cable included in the delivery package. The pin assignment of 50pin connector described in the table below is the same as JP7-TC-1.
PIN Name I/O Description Level
1 RFPC1 O Control output for Trickle-
Power Mode
2 RFPC0 O
Control output for Trickle-
Power Mode
+ 2.85 V DC /
max. 25 mA
+ 2.85 V DC /
max. 25 mA
3 GPIO15 I/O See chapter 6.8.4 CMOS
4 GPIO14 I/O See chapter 6.8.4 CMOS
5 GPIO13 I/O See chapter 6.8.4 CMOS
6 T-MARK O 1 PPS Time Mark Output CMOS
7 GPIO1 I/O See chapter 6.8.4 CMOS
8 GPIO0 I/O See chapter 6.8.4 CMOS
9 GPIO7 I/O See chapter 6.8.4 CMOS
10 GPIO5 I/O See chapter 6.8.4 CMOS
11 GPIO6 I/O See chapter 6.8.4 CMOS
12 GPIO10 I/O See chapter 6.8.4 CMOS
13 RESET_N I Reset the unit if Active Low CMOS
14 V_BAT I Power for RTC and SRAM +3 V DC ±5%
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GPS-RECEIVER JP7-T VERSION 1.02
PIN Name I/O Description Level
15 V_BAT I Power for RTC and SRAM +3 V DC ±5%
16 GND Digital ground
17 GND Digital ground
18 GND Digital ground
19 GND Digital ground
20 VC3.0 O Supply voltage of RF section
+ 3.0 V DC /
max. 25 mA
21 GND Digital ground
22 V_ANT I
Power supply for an active
antenna
Up to +12 V DC/
max. 25 mA
23 GND Digital ground
24 GND Digital ground
25 GND Digital ground
26 GND Digital ground
27 GND Digital ground
28 GND Digital ground
29 GND Digital ground
30 GND Digital ground
31 GND Digital ground
32 GND Digital ground
33 GND Digital ground
34 GND Digital ground
35 GND Digital ground
36 GND Digital ground
37 Vcca O
38 Vcca O
Control output for RF part
Control output for RF part
39 GPIO3 I/O See chapter 6.8.4
+ 2.85 V DC /
max. 25 mA
+ 2.85 V DC /
max. 25 mA
CMOS
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GPS-RECEIVER JP7-T VERSION 1.02
PIN Name I/O Description Level
40 SDI2 I Serial Data Input B CMOS
41 SDO2 O Serial Data Output B CMOS
42 SDO1 O Serial Data Output A CMOS
43 SDI1 I Serial Data Input A CMOS
44 BOOT_SELECT I Boots in update mode, if high CMOS
45 VCC I Main power supply + 3.3 V DC ±5 %
46 VCC I Main power supply + 3.3 V DC ±5 %
47 VCC I Main power supply + 3.3 V DC ±5 %
48 VCC I Main power supply + 3.3 V DC ±5 %
49 VCC I Main power supply + 3.3 V DC ±5 %
50 VCC I Main power supply + 3.3 V DC ±5 %
Antenna pads on the JP7-TC-2, only
1 RF_GND - Analog ground -
2 RF_IN I GPS signal from connected
antenna
50 Ohms @ 1.575
GHz
3 RF_GND - Analog ground -
Table 6: Pin assignment of the JP7-TC-1(-2)
6.8.1 Configuration and timing signals
RESET_N This pin provides an active-low reset input to the
board. It causes the board to reset and to start
searching for satellites. Reset is an optional input
and, if not utilized, it may be left open.
T-MARK This pin provides 1 pulse per second output from
the board, which is synchronized to within 1
microsecond of GPS time. The output is a CMOS
level signal.
BOOT_SELECT Set this Pin to high (+3.3 V DC) for
reprogramming the flash of the JP7-T (for instance
updating a new firmware for the JP7-T ).
RFPC0 RFPC0 pin is provided to the JP7-TB and JP7-TC
module. This pin is a control output for the TricklePower Mode. A possible circuit is shown in figure
below. If the LED lights permanently the GPS
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GPS-RECEIVER JP7-T VERSION 1.02
receiver is searching satellites. Is the GPS receiver
in Trickle-Power Mode, the LED flashes in
rhythm, i.e. the GPS receiver receives valid
positions data (see also figure 6).
Note: By switched off Trickle power the LED
will flash permanently. The reception of
satellites data can be checked by using the TMark, however, can not be evaluated.
Vcc = 3.3 V DC
330
Ω
RFPC0
47 k
Ω
figure 6: The control output for Trickle-Power Mode.
BC817
GND
6.8.2 Serial communication signals
The board supports two full duplex serial channels. All serial connections
are at CMOS levels. If you need different voltage levels, use appropriate
level shifters, (e.g. MAX 3232 from Maxim) in order to obtain RS-232
compatible signal levels (se also chapter 10). All supported variable baud
rates and all can be controlled from the appropriate screens in SiRFdemo
software. You can directly communicate with a PC serial port.
SDI1 This is the main receiving channel and is used to
receive software commands to the board from
SiRFdemo software or from user written software.
SDI2 This is the auxiliary receiving channel and is used
to input differential corrections to the board to
enable DGPS navigation.
SDO1 This is the main transmitting channel and is used to
output navigation and measurement data to
SiRFdemo or user written software.
SDO2 For user’s application.
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GPS-RECEIVER JP7-T VERSION 1.02
6.8.3 DC input signals
VCC This is the main DC power supply for 3,3 V
powered board JP7-T family.
RF_IN Active antennas have an integrated low-noise
amplifier. They can be directly connected to this
pin (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.
Caution: Do not connect or disconnect the
antenna when the JP7-T family is running.
Caution: The RF_IN is always fed from the input
voltage on the V_ANT. Do not use any input
voltage on this pin
V_ANT This pin is an input and reserved for an external
DC power supply for an active antenna.
The antenna bias for an external active antenna can
be provided in two way to pin V_ANT.
In order to use a 5 V or 12 V active GPS antenna,
the V_ANT has to be connected to 5 V, 12 V
external power supply respectively.
The other possibility is available when you connect
the VC3.0 output (which provides 3.0 V) to
V_ANT, so that an antenna with 3.0 V supply
voltage can be used.
Hint: The input voltage on the V_ANT should be
chosen in according to the antenna to be used.
Note: The GPS receiver JP7-T family has to be
connected with an active 3 V GPS antenna
(max. current of 25 mA). The antenna voltage is
provided by the internal power management.
VC3.0 This pin is an output which provides +3.0 V DC,
and can be connected to the V_ANT, to supply the
connected GPS antenna. In Trickle Operation and
Push-To-Fix operation, VC3.0 is switched off
when the receiver sets itself into the sleep mode.
When the receiver wakes up the VC3.0 is switched
on.
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GPS-RECEIVER JP7-T VERSION 1.02
6.8.4 General purpose input/output
Several I/O’s (GPIO0, GPIO1, GPIO3, GPIO5, GPIO6, GPIO7, GPIO10,
GPIO13, GPIO14, GPIO15, please refer to the tables 4, 5, 6) of the CPU are
connected to the hardware interface connector of the JP7-T family. They are
reserved for customer specific applications.
For example:
For realization a SPI-Bus −
− For realization an Antenna-indication.
These pins are not supported by the current GPS firmware.
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GPS-RECEIVER JP7-T VERSION 1.02
7 Software interface
The FALCOM JP7-T family supports NMEA-0183 and SiRF binary
protocols. A short description of these protocols are provided herein.
For more detailed information please refer to the SiRFstarII message set
specification available in the section “service/downloads/manuals” at
FALCOM homepage.
7.1 SiRF binary data message
Table 7 lists the message list for the SiRF output messages.
Hex ASCII Name Description
0 x 02 2 Measured Navigation Data Position, velocity and time
0 x 03 3 True Tracker Data Not implemented
0 x 04 4 Measured Tracking Data Satellite and C/No information
0 x 06 6 SW Version Receiver software
0 x 07 7 Clock Status Current clock status
0 x 08 8 50 BPS Subframe Data Standard ICD format
0 x 09 9 Throughput Navigation complete data
0 x 0A 10 Error ID Error coding for message failure
0 x 0B 11 Command
Successful request
Acknowledgement
0 x 0C 12 Command No
Unsuccessful request
Acknowledgement
0 x 0D 13 Visible List Auto Output
0 x 0E 14 Almanac Data Response to Poll
0 x 0F 15 Ephemeris Data Response to Poll
0 x 10 16 Test Mode 1 For use with SiRFtest (Test Mode 1)
0 x 11 17 Differential Corrections Received from DGPS broadcast
0 x 12 18 Ok To Send CPU ON/OFF (Trickle Power)
0 x 13 19 Navigation Parameters Response to Poll
0 x 14 20 Test Mode 2 Additional test data (Test Mode 2)
0 x 1C 28 Nav. Lib. Measurement Data Measurement Data
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GPS-RECEIVER JP7-T VERSION 1.02
Hex ASCII Name Description
0 x 1D 29 Nav. Lib. DGPS Data Differential GPS Data
0 x 1E 30 Nav. Lib. SV State Data Satellite State Data
0 x 1F 31 Nav. Lib. Initialization Data Initialization Data
0 x FF 255 Development Data Various status messages
Table 7: SiRF Output Messages
Table 8: lists the message list for the SiRF input messages.
Hex ASCII Name Description
0 x 55 85 Transmit Serial Message User definable message
0 x 80 128 Initialize Data Source Receiver initialization and
associated parameters
0 x 81 129 Switch to NMEA Protocol Enable NMEA message, output rate
and baud rate
0 x 82 130 Set Almanac (upload) Sends an existing almanac file to the
receiver
0 x 84 132 Software Version (Poll) Polls for the loaded software version
0 x 85 133 DGPS Source Control DGPS correction source and beacon
receiver information
0 x 86 134 Set Main Serial Port Baud rate, data bits, stop bits and
parity
0 x 87 135 Switch Protocol Obsolete
0 x 88 136 Mode Control Navigation mode configuration
0 x 89 137 DOP Mask Control DOP mask selection and parameters
0 x 8A 138 DGPS Mode DGPS mode selection and timeout
value
0 x 8B 139 Elevation Mask Elevation tracking and navigation
masks
0 x 8C 140 Power Mask Power tracking and navigation
masks
0 x 8D 141 Editing Residual Not implemented
0 x 8E 142 Steady-State Detection – not
Not implemented
used
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GPS-RECEIVER JP7-T VERSION 1.02
Hex ASCII Name Description
0 x 8F 143 Static Navigation Configuration for static operation
0 x 90 144 Poll Clock Status (Poll) Polls the clock status
0 x 91 145 Set DGPS Serial Port DGPS port baud rate, data bits, stop
bits and parity
0 x 92 146 Poll Almanac Polls for almanac data
0 x 93 147 Poll Ephemeris Polls for ephemeris data
0 x 94 148 Flash Update On the fly software update
0 x 95 149 Set Ephemeris (upload) Sends an existing ephemeris to the
receiver
0 x 96 150 Switch Operating Mode Test mode selection, SV ID and
period
0 x 97 151 Set Trickle Power
Parameters
Push to fix mode, duty cycle and on
time
0 x 98 152 Poll Navigation Parameters Polls for the current navigation
parameters
0 x A5 165 Set UART Configuration Protocol selection, baud rate, data
bits, stop bits and parity
0 x A6 166 Set Message Rate SiRF binary message output rate
0 x A7 167 Low Power Acquisition
Parameters
Low power configuration
parameters
0 x B6 182 Set UART Configuration Obsolete
Table 8: SiRF Input Messages
7.2 NMEA data message
The SiRFstarIIe evaluation receiver is capable of outputting data in the
NMEA-0183 format as defined by the National Marine Electronics
Association (NMEA), Standard for Interfacing Marine Electronic Devices,
Version 2.20, January 1, 1997.
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GPS-RECEIVER JP7-T VERSION 1.02
7.2.1 NMEA output messages
Table 9 lists all NMEA output messages supported by SiRFstarIIe
evaluation receiver and a brief description.
Option Description
GGA Time, position and fix type data.
GLL Latitude, longitude, UTC time of position fix and status.
GSA GPS receiver operating mode, satellites used in the position solution and
DOP values.
GSV The number of GPS satellites in view satellite ID numbers, elevation,
azimuth and SNR values.
MSS (This message can be switched on via SiRFdemo software) Signal-to-noise
ratio, signal strength, frequency and bit rate from a radio-beacon receiver.
RMC Time, date, position, course and speed data.
VTG Course and speed information relative to the ground.
Table 9:
7.2.2 NMEA input messages
NMEA Output Messages
Message MID1 Description
Set Serial Port 100 Set PORT A parameters and protocol
Navigation Initialization 101 Parameters required for start using X/Y/Z2
Set DGPS Port 102 Set PORT B parameters for DGPS input
Query/Rate Control 103 Query standard NMEA message and/or set
output rate
LLA Navigation Initialization 104 Parameters required for start using
Lat/Lon/Alt3
Development Data On/Off 105 Development Data messages On/Off
MSK Receiver Interface MSK Command message to a MSK radio-beacon
receiver.
Table 10: NMEA Input Messages
1. Message Identification (MID).
2. Input co-ordinates must be WGS84.
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3. Input co-ordinates must be WGS84.
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GPS-RECEIVER JP7-T VERSION 1.02
Note: NMEA input messages 100 to 105 are SiRF proprietary
NMEA messages. The MSK NMEA string is as defined by the
NMEA 0183 standard.
7.2.3 Transport Message
Start Sequence Payload Checksum End Sequence
$PSRF<MID>
1. Message Identifier consisting of three numeric characters. Input messages begin at MID 100.
2. Message specific data. Refer to a specific message section for <data>...<data>definition.
3. CHECKSUM is a two-hex character checksum as defined in the NMEA specification. Use of
checksums is required on all input messages.
4. Each message is terminated using Carriage Return (CR) Line Feed (LF) which is \r\n which is hex
0D 0A. Because \r\n are not printable ASCII characters, they are omitted from the example
strings, but must be sent to terminate the message and cause the receiver to process that input
message.
CheckSum
1
Data2 *CKSUM3 <CR> <LF>4
The checksum is 15-bit checksum of the bytes in the payload data. The
following pseudo code defines the algorithm used.
Let message to be the array of bytes to be sent by the transport.
Let msgLen be the number of bytes in the message array to be transmitted.
Clearly to say, the string over which the checksum has to be calculated is
between the “$” and “*” (without characters “$” and “*”).
Index = first
checkSum = 0
while index < msgLen
checkSum = checkSum + message[index]
checkSum = checkSum AND (2
15
-1).
Note: All fields in all proprietary NMEA messages are required,
none are optional. All NMEA messages are comma delimited.
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GPS-RECEIVER JP7-T VERSION 1.02
8 Mechanical draw
The following chapters describe the mechanical dimensions of JP7-T family
and give recommendations for integrating JP7-T family into the user
application. Note that, the absolute maximum dimension for all modules
(JP7-T, JP7-TB, JP7-TC-1, JP7-TC-2) is: 25.4 mm x 25.4 mm (L x B).
Figure 7 shows the top view on JP7-T family (without connectors) and
provides an overview of the mechanical dimensions of the board.
Please note that, the JP7-T family has a dimension tolerance from ±0.1
mm.
3mm
2.24 mm
0.90 mm
25.4 mm
25.4 mm
Figure 7: The mechanical draw of the JP7-T family
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GPS-RECEIVER JP7-T VERSION 1.02
m
Figure 8 shows the bottom view on JP7-TB and provides an overview of the
mechanical dimensions of the pointed balls.
22.20 mm
20.70 mm
19.70 mm
18.70 mm
17.20 mm
15.70 mm
14.20 mm
12.70 mm
11.20 mm
9.70 mm
8.20 mm
6.70 mm
5.70 mm
3.20 mm
1.70 mm
23.70 mm
22.70 mm
21.70 mm
21.20 mm
20.20 mm
18.70 mm
17.20 mm
15.70 mm
14.20 mm
12.70 mm
11.20 mm
9.70 mm
8.20 mm
6.70 mm
5.20 mm
4.20 mm
3.70 mm
2.70 mm
1.70 mm
m
0
0
.
1
Round ball diameter
Square ball dimentions
2.20 mm
2.20 mm
Figure 8
: The mechanical draw of the JP7-TB
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Page 40
GPS-RECEIVER JP7-T VERSION 1.02
r
s
Figure 9 shows the bottom view on JP7-TC-1(-2) and provides an overview
of the mechanical dimensions of the integrated 50-pin connector and RF
connector.
50
1
1.67 mm
12.7 mm
12.7 mm
21.7 mm
Figure 9: The mechanical draw of the JP7-TC-1
50
1
26
25
RF
Connecto
26
25
1.70 mm
1.67 mm
12.7 mm
RF
12.7 mm
antenna pad
20.25 mm
21.7 mm
23.20 mm
O 1.00 mm
Round ball
2.20 mm
Square pads
for an antenna
cable
1.05 mm
Figure 10
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: The mechanical draw of the JP7-TC-2
Page 41
GPS-RECEIVER JP7-T VERSION 1.02
A
y
9 Layout recommendation
9.1 Ground planes
JP7-T GPS receiver needs two different ground planes. The pins RF_GND
(Pins 11, 12, 13, 14, 15, 16, 18) shall be connected to analog ground, the
pins GND (Pins 2, 10, 30) to digital ground.
The two ground planes shall be separated :
the planes are connected inside the receiver (see Figure 11). ♦
Digital GND
Figure 11: Ground plane of the JP7-T family GPS receiver
9.2 RF connection
The JP7-T family GPS receiver is designed to be functional by using either
a passive patch antenna or an antenna connector with standard RF cables. In
order to make a RF connection properly, the user has to connect the antenna
points or the pins of the connector to the RF pin (pin 17) and RF grounds
(GND’s of RF part), respectively (see Figure 11)
connected internall
nalog GND
RF connector feed
Figure 12: RF connection to antenna feed of the JP7-T GPS receiver.
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GPS-RECEIVER JP7-T VERSION 1.02
4
To make a properly antenna connection to the antenna pads (available on
bottom side of JP7-TC-2, only) refer to the figure below which shows their
position and pin name (refer also on the table 6).
Figure 13: RF connection to antenna feed of the JP7-TC-2 GPS receiver.
Recommendations for layout, and soldering.
Please note that, the dimension tolerance is ±0.1 mm.
2.0
0.8
1.9
2.8
25.
1.277
1.5
25.4
Figure 14:
Recommendations for layout.
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Page 43
GPS-RECEIVER JP7-T VERSION 1.02
empera
e
)
Recommended soldering reflow profile for JP-T family mounting on PCB
10 sec.
240 C
250
3-5 C / sec
°
200
tur
150
T
100
50
Prehea ting
3-9 C / sec
°
100 sec.
°
1-5 C / sec
°
200 - 220 sec.
Time (sec
Figure 15:
Typical solder conditions (temperature profile, reflow conditions).
Consider for a long time in the soldering zone (with temperature higher than
180°C) has to be kept as short as possible to prevent component and
substrate damages. Peak temperature must not exceed 240°C. JP7-T family
are able to withstand twice the previous recommended reflow profile in
order to be compatible with a double reflow when SMDs are mounted on
both sides of the PCB. A maximum of two soldering reflows are allowed for
these packages. The use of a no clean flux is highly recommended to avoid
any cleaning operation. In order to prevent any bump cracks, ultrasonic
cleaning methods are not recommended.
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Page 44
GPS-RECEIVER JP7-T VERSION 1.02
10 First steps to make it work
Figure 16
: The minimum hardware interface of JP7-T to get started.
- Antenna: The antenna connection is the most critical part of PCB
routing. Previously placing the JP7-T on the PCB secure that
the connection to the antenna signals is routed. In order to
make it properly functional a control impedance line has to
connect the RF_IN signal with antenna feed points or antenna
connector, respectively. The routing on the PCB depends on
your choice.
- Power: The input power is also very important as far as the minimum
and maximum voltage is concerned. The power supply of JP7T family has to be a single voltage source of VCC at 3.3 VDC.
The power supply has to be able to provide a sufficient current
which typically rises to 200 mA. Please, connect GND pins to
ground, and connect the line which supply the VCC pin to +3.3
V, properly. If they are correctly connected, a proper RESET
signal is internally generated the board is full powered and the
unit begins obtaining its position fix.
- Serial Interface: The JP7-T family provides two serial interfaces. Each
interface is provided with two-wire the SDI1, SDO1 supports
line and ground for the first serial interface (port A) and SDI2,
SDO2 supports line and ground for the second serial interface
(port B). These pins are both 3.3 V CMOS and 5 V TTL
compatible. In order to use different voltage levels, a
appropriate level shifters has to be used.
E. g. in order to provide RS232 compatible levels use the 3 V
compatible MAX3232 transceiver from Maxim or others based
on the required levels. The GPS data will be transmitted
through port A (first serial port), if an active antenna is
connected, which has a good view to sky (no obstacle). You
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Page 45
GPS-RECEIVER JP7-T VERSION 1.02
can use port B (second serial port) to feed in DGPS correction
data. Pull-up (100 kΩ) unused SDI inputs.
- Active Antenna Bias Voltage: The output voltage at the antenna cable
can be used to power the bias voltage of the antenna, provided
can make sure that the antenna runs down to 2.7 V bias voltage
and the current does not exceed 20 mA.
- Backup Battery: In order to allow the GPS receiver to perform
internally the warm and hot start it is advisable to connect the
V_BAT pin to an external backup battery. For more
information on cold, warm, and hot-start scenarios, please refer
to the Section 6.3 “ Start-Up”. In case of a power interruption
on pin VCC the real-time clock and backed-up SRAM are
continually supplied through V_BAT. The voltage at this pin
has to be +3 V DC ±5%. If you do not use a backup battery,
connect this pin to GND or leave it open. Do not use a super
cap for the battery backup supply (recommended by SiRF).
The quickest way to get first results with the JP7-T is to use the JP7-T
Evaluation board together with the program SiRFdemo.
Figure 17: JP7-T Evaluation board
The Evaluation board contains:
- Evaluation Box
- JP7-T sample with soldered antenna cable.
- power supply (AC/DC adapter, Type FW738/05, Output 5VDC 1.3 A)
- active GPS antenna (FAL-ANT-3)
- RS232 level shifter
- RS232 cable to your computer.
The Evaluation board with contained components are not included in the
delivery package. In order to have one the users of JP7-T family have to
purchase it.
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Page 46
GPS-RECEIVER JP7-T VERSION 1.02
Figure 18: Example of using of the SiRFdemo
The SiRFdemo manual and software are available on the Falcom’s Website
for free download:
Î www.falcom.de/service/downloads/manual/SiRF/SiRFdemo.pdf
Î www.falcom.de/service/downloads/manual/SiRF/SiRFdemo.zip
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Page 47
GPS-RECEIVER JP7-T VERSION 1.02
11 Appendix
11.1 Board-to-board connector
This chapter provides specifications for the 50-pin board-to-board connector
which serves as physical interface to the host application. The receptacle
assembled on the JP7-TC is type Hirose DF12C. Mating headers from
Hirose are available in different stacking heights.
Figure 19.a: Hirose DF12C receptacle on JP7-TC Figure 19.b: Header Hirose
DF12C
11.2 RF connector
The JP7-TC uses an ultra-miniature SMT antenna connector supplied from
Hirose Ltd.
The product name is:
• U.FL-R-SMT
The position of the antenna connector on the JP7-TC board has to be seen
on bottom side on the upper right corner.
Mating plugs and cables can be chosen from the Hirose U.FL Series.
Examples are shown in figure below. For latest product information please
contact your Hirose dealer or visit the Hirose home page, for example
http://www.hirose.com.
Figure 20: Mechanical dimensions of U.FL-R-SMT connector with U.FL-LP-040 plug
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Page 48
GPS-RECEIVER JP7-T VERSION 1.02
11.3 Firmware Interface
The table below shows supported SiRF firmware versions into the JP7-T
family devices.
GPS
Receiver
2.20 2.32 SiRFXTrac2 SiRFDrive
Supported SiRF internal firmware version
JP7-T X X X
JP7-TB X X X X
JP7-TC-1 X X X X
JP7-TC-2 X X X X
11.4 XTrac firmware description
The JP7-T family using SiRFXTrac2 software offers high position accuracy
and fast Time-To-First-Fix (TTFF) than is currently possible with other
autonomous GPS solution. This means that the JP7-T family will continue
to determinate its positions or obtain an initial fix in places where previously
not possible. When the GPS receiver loaded with SiRFXTrac2 is initially
turned on, it begins to determinate its current positions, velocity and time
which will be calculated from tracking the GPS signals an extremely small
level by 16 dBHz. While trying to calculate a position fix, the receiver needs
to be locked-on to at least four satellites. Your position can be extremely
quick fixed within 4 seconds instead of within 8 seconds using other GPS
software from a "hot-start" state, and within 45 seconds from a "cold-start"
state.
As a general note, the SiRFdemo v3.61 supports the additional functionality
and configuration of SiRFXTrac2.
This software is now available on the Falcom’s Website for free download:
Î www.falcom.de/service/downloads/manual/SiRF/SiRFdemo3.61.zip
11.4.1 SiRFXTrac2 firmware default settings
All GPS units which use the SiRFXTrac2 firmware version have the
following settings on serial interfaces:
SDI1/SDO1 (first serial port):
NMEA 38400 baud, Msg.: GLL, GGA, RMC,
VTG, GSV,
GSA
8 data bits, no parity, 1 stop bit
SDI2/SDO2(second serial port):
RTCM, 38400 baud
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GPS-RECEIVER JP7-T VERSION 1.02
11.4.2 Order options
As far as the SiRFXTrac2 firmware is concerned the products listed below
with specific requirements are also available upon request:
Name
JP7-TX SiRFXTrac2
Using firmware
version
Options
30-pin out on the left and right side of JP7-T
are available for use
JP7-TBX SiRFXTrac2 48 Balls are available for use
JP7-TCX-1 SiRFXTrac2
A 50-pin connector and a RF connector are
available for use
A 50-pin connector and solder pads for an
JP7-TCX
JP7-TCX-2 SiRFXTrac2
antenna cable are available for use.
There is no antenna cable included in the
delivery package.
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Page 50
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