Furuno GV-86, eRideOPUS 7, GV-87, eRideOPUS 6 User Manual

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www.furuno.com

FURUNO GNSS Receiver

eRideOPUS 6/ eRideOPUS

Model

GV-86/ GV-87

Dead Reckoning Solution

User’s Guide

(Document No. SE16-900-002-00)

eRideOPUS 6/ eRideOPUS 7 GV-86/ GV-87

Dead Reckoning User’s Guide

SE16-900-002-00

Important Notice

No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, for any purpose without the express written permission of the publisher, FURUNO ELECTRIC CO., LTD.

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eRideOPUS 6/ eRideOPUS 7 GV-86/ GV-87

Dead Reckoning User’s Guide

SE16-900-002-00

Revision History

Revision

Description

Date

Initial release

2017.10.24

eRideOPUS 6/ eRideOPUS 7 GV-86/ GV-87

Dead Reckoning User’s Guide

SE16-900-002-00

Table of Contents

1 General Description ············································································································· 1 2 FURUNO DR GNSS Receiver ································································································ 1 3 System Configuration ·········································································································· 2

3.1 Available Signal Combination and Supported Sensor ······················································· 2

3.2 Sensor Interface Configuration ······················································································· 3

4 Reference Circuit ················································································································ 4

4.1 SMI130 ························································································································ 4

4.2 MPU-6500 ···················································································································· 5

4.3 XV-4001BC and AIS328DQ ····························································································· 6

4.4 ITG-3500 and AIS328DQ ································································································· 7

4.5 A3G4250D and AIS328DQ ······························································································ 8

4.6 XV-8000CB and AIS328DQ ····························································································· 9

4.7 XV-8100CB and AIS328DQ ···························································································· 10

5 IMU Sensor Installation ······································································································ 12

5.1 Automatic Correction by Auto Orientation Function························································· 13

5.2 Expand Auto Orientation Range by PERDAPI,AUTOORIENT Command ····························· 13

5.3 Set Installation Angle by Misalignment ··········································································· 14

5.4 Sensor Installation Examples ························································································ 15

5.4.1 Zero Angle against Axis of IMU Sensor ···································································· 15

5.4.2 Auto Orientation Default Range ·············································································· 16

5.4.3 Auto Orientation Expansion Range ········································································· 17

5.4.4 Out of Auto Orientation Range ················································································ 18

6 Calibration ······················································································································· 19

6.1 Power on to GNSS Position Fix ····················································································· 19

6.2 GNSS Position Fix to DR Valid by Calibration Driving ······················································ 20

6.3 Calibration of Vehicle Speed Pulse and Accelerometer ···················································· 20

6.4 Calibration of Gyro Sensor ··························································································· 21

6.5 Aging and Temperature Fluctuations ············································································· 21 7 Operating of DR Backup ···································································································· 22 8 Recommended NMEA Output Sentence at Customer Evaluation Stage ··································· 22 9 Important Notice ··············································································································· 23

9.1 Important Notice for IMU Sensor ···················································································· 23

9.2 Characteristics of IMU Sensor ······················································································· 23

9.3 Layout Design against Influence of IMU Sensor by External Environment Factor ················ 23

9.4 Calibrating Operation ··································································································· 23

9.5 Receiver Start Operation ······························································································ 24 10 FAQ ······························································································································ 25

eRideOPUS 6/ eRideOPUS 7 GV-86/ GV-87

Dead Reckoning User’s Guide

SE16-900-002-00

1 General Description

This document describes user’s guide for achieving best performance of FURUNO Dead Reckoning (DR) GNSS receiver (GNSS+DR receiver).

- eRideOPUS 6 (P/N: ePV6010B) Dead Reckoning Chip solution

- eRideOPUS 7 (P/N: ePV7010B) Dead Reckoning Chip solution

- GV-8720

- GV-8620 Available software: As from ENP6.33D GNSS+DR receiver has the following external interface for DR function. <Signal input from sensor or vehicle>

This configuration is the way of direct input from vehicle.

- FURUNO supported gyro sensor and accelerometer.

- Vehicle speed pulse signal.

- Vehicle reverse signal.

2 FURUNO DR GNSS Receiver

GNSS+DR receiver can keep the following high accuracy position and velocity performance under non GNSS signal reception or unstable area

GNSS stand alone

GNSS+DR hybrid / DR only

GNSS stand alone

GNSS+DR hybrid

Figure 2.1 Ground Tracking Test of GNSS Stand Alone and GNSS+DR

(Upper: Tunnel, Lower: Urban Canyon)

eRideOPUS 6/ eRideOPUS 7 GV-86/ GV-87

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3 System Configuration

3.1 Available Signal Combination and Supported Sensor

Table 3.1 shows available signal source combinations. Based on Table 3.2, which shows FURUNO supported IMU sensor (Gyro, Accelerometer and Gyro/Accelerometer combo sensor), please design optimized system on customer platform.

Table 3.1 Signal Source Combination

Combination

Gyro

Accelerometer

Vehicle

speed

pulse

(*1)

Reverse signal

(*1)

Notes

Detection of elevation pitch angle is available.

B -

: Necessary signal source

Table 3.2 Supported Gyro Sensor and Accelerometer

(*2)

Sensor category

Product number

Vendor

# of axis

Automotive

Gyro/Accelerometer

combo sensor

SMI130

Bosch

MPU-6500

InvenSense

Gyro sensor

XV-4001BC

Seiko Epson

ITG-3500

InvenSense

3 A3G4250D

STMicroelectronics

3 XV-8000CB

(*3)

Seiko Epson

XV-8100CB

(*4)

Seiko Epson

Accelerometer

AIS328DQ

STMicroelectronics

3 LIS331DLH

STMicroelectronics

Notes:

(*1) Specification of vehicle speed pulse and reverse signal Please check the regulation and electric characteristics by GNSS+DR receiver data sheet and keep it, otherwise customer may have risk of out of performance guarantee. It is necessary to take vehicle speed pulse together reverse signal.

(*2) Supported IMU sensor We verified that GNSS+DR receiver with sensor in Table 3.2 could achieve target performance by proper calibration described at Chapter 6.

(*3) In case of using XV-8000CB, it is necessary to implement the following devices.

-AD convertor (ADS1100A3: Texas Instruments)

-Thermo sensor (LM73CIMKX-0: Texas Instruments)

-Level shifter from 5V to 3V (*4) In case of using XV-8100CB, it is necessary to implement the following devices.

-AD convertor (ADS1100A3: Texas Instruments)

-Thermo sensor (LM73CIMKX-0: Texas Instruments)

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3.2 Sensor Interface Configuration

Figure 3.1shows I/O relation between the GNSS+DR receiver and the supported sensor in Table 3.2.

Sensor information

I/O signal

Pin #

ePV6010B /

ePV7010B

GV-86/

GV-87

Gyro sensor,

I2C serial clock (SCL)

TXD2_SCL

#19

Accelerometer,

Gyro/Accelerometer combo sensor

I2C serial data (SDA)

RXD2_SDA

#18

Vehicle speed pulse

ECNT

Reverse signal

GPIO

FURUNO Dead Reckoning GNSS Receiver

ECNT

GPIO

RXD2_SDA

TXD2_SCL

RXD1

TXD1 Output data (Position, Time, Sensor status, …)

Command data (NMEA setting, Mis-alignment, …)

I2C serial address and data between sensor block

I2C serial clock from sensor block

Vehicle speed pulse

Reverse signal

UART1

I2C

Figure 3.1 Sensor Interface Configuration Block Level Diagram

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Dead Reckoning User’s Guide

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4 Reference Circuit

This section shows reference circuits of FURUNO supported sensor. Operation guarantee of these circuits is just based on FURUNO original development environment, which means that FURUNO is not able to guarantee operation at customer development environment. Therefore, please verify and check expected operation at customer end.

For example, in the schematics below, the both I2C lines (TXD2_SCL, RXD2_SDA) are pulled up with the 10kΩ resistors (R1, R2). Depending on the wiring capacity of the I2C line, the H and L levels may deviate from the specified values, or the rising slope may become slow, causing timing errors. In such a case, it can be adjusted by decreasing the value of the pull-up resistors (R1, R2) within the range that the IC can drive. Since the wiring capacity varies according to the customer's actual layout of the circuit board, the design should be decided by customer's evaluation.

4.1 SMI130

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.1 Reference Circuit of SMI130

SCL

SDA

R2 10k

0.1uF

R1 10k

0.1uF

SMI130

INT2

VDD

GND

CSB2

GNDIO

SCK

SDI

SDO2

VDDIO

INT3

INT4

CSB1

SDO1

INT1

VCC

(*1)

(*2)

(*3)

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4.2 MPU-6500

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

RESET

External reset signal

NRST

RST_N

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.2 Reference Circuit of MPU-6500

XC8101AA01-GR-G

VOUT

VSS

VIN

R2 10k

VCC

R1 10k

VCC

SDA

SCL

RESET

MPU-6500

AUX_CL7VDDIO8SDO/AD09REGOUT10FSYNC11INT

VDD

GND

RESV

AUX_DA

nCS

CSL/SCLK

SDA/SDI

0.1uF

0.01uF

VCC

(*4)

(*3)

(*1)

(*2)

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4.3 XV-4001BC and AIS328DQ

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

RESET

External reset signal

NRST

RST_N

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.3 Reference Circuit of XV-4001BC and AIS328DQ

R1 10k

R2 10k

VCC

XC8101AA01-GR-G

VOUT

VSS2CE

VIN

SDA

RESET

SCL

AIS328DQ

INT_2

Reserv ed

VDD

GND

INT_17GND8GND9GND10SPC/SCL11CS

Reserv ed

VDD_IO

SDO/SA0

SDI/SDO/SDA

19NC20NC21NC22NC23NC24

C3 10uF

0.1uF

VCC

XV-4001BC

Reserv ed

SCL

VDD

Reserv ed5Reserv ed

GND

MOSI

SDA

Reserv ed

VCC

C2 10uFC10.1uF

(*1)

(*4)

(*3)

(*2)

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4.4 ITG-3500 and AIS328DQ

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

RESET

External reset signal

NRST

RST_N

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.4 Reference Circuit of ITG-3500 and AIS328DQ

AIS328DQ

INT_2

Reserv ed

VDD

GND

INT_17GND8GND9GND10SPC/SCL11CS

Reserv ed

VDD_IO

SDO/SA0

SDI/SDO/SDA

19NC20NC21NC22NC23NC24

VCC

C5 10uF

0.1uF

XC8101AA01-GR-G

VOUT

VSS2CE

VIN

0.1uF

ITG-3500

SDA/SDI

VDDIO

/CS

RESV5AD0/SD06REGOUT7FSYNC

VDD

INT

GND

RESV-G

14NC15

SCL/SCLK

0.1uF

0.01uF

VCC

R2 10k

R1 10k

VCC

RESET

SDA

SCL

(*4)

(*3)

(*1)

(*2)

eRideOPUS 6/ eRideOPUS 7 GV-86/ GV-87

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4.5 A3G4250D and AIS328DQ

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

RESET

External reset signal

NRST

RST_N

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.5 Reference Circuit of A3G4250D and AIS328DQ

R1 10k

A3G4250D

Vdd_IO

SCL/SPC

SDA/SDI/SDO

SDO/SA0

CS5DRDY/INT26INT7RES

RES

GND

PLLFILT

RES

VDD

R3 10k

R2 10k

0.1uF

VCC

C2 10uF

C4 0.47uF

C1 0.01uF

0.1uF

XC8101AA01-GR-G

VOUT

VSS2CE

VIN

SDA

RESET

SCL

AIS328DQ

INT_2

Reserv ed

VDD

GND

INT_17GND8GND9GND10SPC/SCL11CS

Reserv ed

VDD_IO

SDO/SA0

SDI/SDO/SDA

NC19NC20NC21NC

22NC23NC24

C7 10uF

0.1uF

VCC

(*4)

(*3)

(*1)

(*2)

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4.6 XV-8000CB and AIS328DQ

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

RESET

External reset signal

NRST

RST_N

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.6 Reference Circuit of XV-8000CB and AIS328DQ

2.2uF

VCCI_3V3

LM73CIMKX-0

ADDR

GND

VDD3SMBCLK

ALERT_N

SMBDAT

0.1uF

R6 10k

VCCI_3V3

R5 10k

AIS328DQ

INT_2

Reserv ed

VDD

GND

INT_17GND8GND9GND10SPC/SCL11CS

Reserv ed

VDD_IO

SDO/SA0

SDI/SDO/SDA

NC19NC20NC21NC22NC23NC

VCC_3V3

C11 10uF

C10

0.1uF

VCCI_3V3

XC8101AA01-GR-G

VOUT

VSS2CE

VIN

VCC_3V3

RESET

VCCI_3V3

XC8101AA01-GR-G

VOUT

VSS2CE

VIN

VCC_5V0

VCCI_3V3

VCCI_5V0

C8 1uF

0.1uF

R1 3.3k R2 3.3k

2.2uF

XV-8000CB

GND

VDD

VOUT

VTEMP

VCCI_5V0

3.3k +/- 1%

VCCI_5V0

VCCI_3V3

0.1uF

VCCI_5V0

TCA9517DGKR

VCCA

SCLA

SDAA

GND

SDAB

SCLB

VCCB

0.1uF

SCL

SDA

ADS1100A3IDBVT

Vin+

GND

SCL3SDA

VDD

Vin-

VCCI_5V0

R8 10k

R7 10k

VCCI_5V0

0.1uF

(*4)

(*3)

(*1)

(*5)

(*6)

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4.7 XV-8100CB and AIS328DQ

I/O signal

Description

Interface connection destination

eRideOPUS 6/7

GV-86/ 87

RESET

External reset signal

NRST

RST_N

SCL

I2C clock

TXD2_SCL

SDA

I2C address/data bus

RXD2_SDA

Figure 4.7 Reference Circuit of XV-8100CB and AIS328DQ

0.1uF

VCCI_3V3

LM73CIMKX-0

ADDR

GND

VDD

SMBCLK

ALERT_N

SMBDAT

0.1uF

VCCI_3V3

R4 10k

R3 10k

XC8101AA01-GR-G

VOUT

VSS

VIN

VCC_3V3

RESET

XC8101AA01-GR-G

VOUT

VSS

VIN

VCCI_3V3

VCC_3V0VCCI_3V0

0.1uF

R13.3k

2.2uF

VCCI_3V0

SDA

SCL

ADS1100A3IDBVT

Vin+

GND

SCL

SDA

VDD

Vin-

VCCI_3V0

0.1uF

XV-8100CB

GND4VOUT

VREF

VDD

R23.3k

(*7)

(*4)

(*3)

(*1)

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Notes:

(*1) When the I2C master device is eRideOPUS 6/eRideOPUS 7 and using 1.8V I/O power supply, please

change to 3.3V I/O signal voltage with level shifter.

(*2) The power supply (VCC) should be common with the receiver.

(*3) Since this resistance value may not satisfy the electrical characteristics due to the floating capacitance of

the line, please decide the resistance value in consideration of the floating capacitance of the line.

(*4) In case only receiver which is eRideOPUS 6/ eRideOPUS 7 or GV-86/GV-87 (I2C master device) has

reset from normal operation, there is a risk of misreading data from sensor after releasing reset. In order to avoid this issue, it is necessary to be activating reset of sensor when I2C master device has reset. Therefore, it is necessary to control power supply of sensor by using power switch with the reset control port due to no reset port at the sensor.

(*5) In case of using XV-8000CB, it is necessary to implement the following devices.

- AD convertor (ADS1100A3: Texas Instruments).

- Thermo sensor (LM73CIMKX-0: Texas Instruments).

- Level shifter from 5V to 3.3V. (*6) 1% resistor is necessary.

(*7) In case of using XV-8100CB, it is necessary to implement the following devices.

- AD convertor (ADS1100A3: Texas Instruments).

- Thermo sensor (LM73CIMKX-0: Texas Instruments).

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5 IMU Sensor Installation

For the installation of the IMU sensor, the GNSS+DR receiver has specification values for the inclination and the deviation of the coordinate system of the vehicle and the IMU sensor. The GNSS+DR receiver has a function to correct the inclination and the deviation within the specification value.

(1) Method of automatically correcting the inclination and the deviation of installation angle by the Auto

Orientation function

(2) Method of presetting the inclination of the known installation angle by the misalignment command With these functions, it is possible to correct and eliminate the output error of the IMU sensor caused by the

inclination and deviation. The Auto Orientation function can also expand the range of angles that can be automatically corrected by

AUTOORIENT command.

Here are definitions of axis against sensor unit installation angle:

- Direction of forward movement: X-axis

- Horizontal to the direction of movement: Y-axis

- Vertical to the direction of movement: Z-axis Rotation angles to the each axis are defined as follows:

- Rotation angle around the X axis: ΔθX Roll angle

- Rotation angle around the Y axis: ΔθY Pitch angle

Rotation angle around the Z axis: ΔθZ Yaw angle

Figure 5.1 (a) to (d) shows inclination against each axis.

(a) No inclination

(b) Inclines ΔθZ to the direction of movement

(d) Inclines ΔθY to the height direction

Δθ

Surface

Direction of

movement

Δθ

Figure 5.1 Sensor Unit Installation Angle Definition

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When the axis described in the IMU sensor data sheet defines the Z-axis and the Y-axis opposite to the DR receiver axis definition, the DR receiver changes the Z-axis and Y-axis direction to correspond to the definition described in this document.

5.1 Automatic Correction by Auto Orientation Function

Auto Orientation is a function to automatically correct the output error due to the inclination and deviation of the IMU sensor. Table 5.1 shows the IMU sensor combination and the allowable angle range in which the Auto Orientation operates.

Table 5.1 Functional Range of Auto Orientation (Default)

Sensor combination

ΔθZ

Yaw angle

ΔθX

Roll angle

ΔθY Pitch angle

Notes

3-axis gyro sensor, 3-axis accelerometer, vehicle speed pulse

±15

±60

2 ±45

±45

In case of using A3G4250D

1-axis gyro sensor, 3-axis accelerometer, vehicle speed pulse

±15

±30

3-axis or 1-axis gyro sensor, vehicle speed pulse

±15

5.2 Expand Auto Orientation Range by PERDAPI,AUTOORIENT Command

In case of using 3-axis gyro sensor, 3-axis accelerometer and vehicle speed pulse, it is possible to expand the Auto Orientation range for the Roll angle or the Pitch angle by $PERDAPI,AUTOORIENT,1*6E. Table 5.2 shows the expanded range.

Table 5.2 Functional Range of Auto Orientation (Expansion)

Sensor

combination

ΔθZ

Yaw angle

ΔθX

Roll angle

ΔθY

Pitch angle

Notes

3-axis gyro sensor, 3-axis accelerometer, vehicle speed pulse

±15

±75

Pitch angle expansion

Using SMI130, MPU6500/ ITG3500

±180

±45

Roll angle expansion

Using SMI130, MPU6500/ ITG3500

±45

-165 to -180

+165 to +180

±45

Roll angle expansion

Using A3G4250D

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5.3 Set Installation Angle by Misalignment

When the IMU sensor is not installed within the Auto Orientation range, which means that the installation angle is exceeded the range described in Table 5.1 and Table 5.2, it is possible to set the installation angle by the misalignment command

(*1)

(Gyro sensor: PERDAPI,GYROALIGN, Accelerometer: PERDAPI,ACCELALIGN).

Misalignment operating necessity condition and flow is as follow: Operating necessity condition:

- Initial installation

- Change installation angle.

Operating process flow:

1. Install the unit with IMU sensor.

2. Check the installation angle of IMU sensor.(delta angle)

3. Operate the GNSS+DR receiver with vehicle stop condition.

4. Send $PERDAPI,STOP,DRPARK*5D command and stop normal operating of GNSS+DR receiver.

5. Send delta angle by misalignment set command. (Gyro sensor misalignment command)

$PERDAPI,GYROALIGN,Δθx,Δθy,Δθz*hh

(Accelerometer sensor misalignment command)

$PERDAPI,ACCELALIGN,Δθx,Δθy,Δθz*hh

*Setting sequence of misalignment angle against absolute axis is ΔθX -> ΔθY -> ΔθZ.

6. Send $PERDAPI,START,SIMCOLD*48 command and initiate normal operating GNSS+DR receiver.

(*2)

Notes:

(*1) As the misalignment data returns to the default in the following condition, it is recommended to register the

commands in ESIPLIST.

- Send PERDAPI,STOP,DRPARK command

- Power off

- Hardware reset

(*2) Do not change the installation angle of IMU sensor during normal operating.

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5.4 Sensor Installation Examples

Here are sensor, which is 3-axis gyro and 3-axis accelerometer, installation examples with the GNSS+DR receiver evaluation kit (VN-871 or VN-861).

5.4.1 Zero Angle against Axis of IMU Sensor

Traveling

direction

This installation is ideal, which means that this installation angle meets requirement specifications of IMU sensor based on data sheet.

(a) (ΔθX, ΔθY, ΔθZ) = (0, 0, 0)

Figure 5.2 Zero Angle against Axis of IMU Sensor

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5.4.2 Auto Orientation Default Range

In case of Figure 5.3 (b), (c) and (d), it is possible to automatically correct the inclination of IMU sensor by using 3-axis gyro sensor and 3-axis accelerometer.

Traveling

direction

+15°

This installation is that the rotate angle against Z-axis is +15 degrees, which means that heading of IMU sensor is -15 degrees at clockwise against traveling direction.

(b) (ΔθX, ΔθY, ΔθZ) = (0, 0, +15)

Traveling

direction

-15°

This installation is that the rotate angle against X-axis is -15 degrees, which means that horizontal plane of IMU sensor is -15 degrees at counter clockwise against Y-axis.

Traveling

direction

+30°

This installation is that the rotate angle against Y-axis is +30 degrees, which means that elevation angle of IMU sensor is +30 degrees against traveling direction.

(d) (ΔθX, ΔθY, ΔθZ) = (0, +30, 0)

Figure 5.3 Installation Examples within Auto Orientation Default Range

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5.4.3 Auto Orientation Expansion Range

In case of Figure 5.4 (e), (f) and (g), it is possible to automatically correct the inclination of IMU sensor by using 3-axis gyro sensor and 3-axis accelerometer and “$PERDAPI,AUTOORIENT,1*6E” command.

+75°

Traveling

direction

This installation is that the rotate angle against Y-axis is +75 degrees, which means that elevation angle of IMU sensor is +75 degrees against traveling direction.

(e) (ΔθX, ΔθY, ΔθZ) = (0, +75, 0)

Traveling

direction

+180°

This installation is that the rotate angle against X-axis is +180 degrees, which means that the top side of IMU sensor faces downward.

(f) (ΔθX, ΔθY, ΔθZ) = (+180, 0, 0)

Traveling

direction

+180°

+45°

This installation is that the rotate angle against X-axis is +180 degrees and against Y-axis is +45 degrees, which means that the top side of IMU sensor faces downward and the elevation angle inclines +45 degrees.

(g) (ΔθX, ΔθY, ΔθZ) = (+180, +45, 0)

Figure 5.4 Installation Examples within Auto Orientation Expansion Range

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5.4.4 Out of Auto Orientation Range

In case of Figure 5.5 (h), (i) and (j), it is necessary to set misalignment data due to out of Auto Orientation range.

Traveling

direction

+30°

This installation is that the rotate angle against Z-axis is +30 degrees, which means that the heading of IMU sensor is +30 degrees at clockwise against the traveling direction. When the heading error is more than +15 degrees, it is necessary to set misalignment data. In this case (the rotate angle against Z-axis is +30 degrees), since ΔθZ is out of Auto Orientation range, it is necessary to send the following commands as misalignment data. $PERDAPI,GYROALIGN,0,0,30*16 $PERDAPI,ACCELALIGN,0,0,30*5D

(h) (ΔθX, ΔθY, ΔθZ) = (0, 0, +30)

+90°

Traveling

direction

This installation is that the rotate angle against X-axis is +90 degrees and the rotate angle against Z-axis is +90 degrees, which means that heading of IMU sensor is +90 degrees at clockwise and the elevation angle of IMU sensor is +90 degrees against the traveling direction. In this case, since

Δθ

and ΔθZ is out of Auto Orientation range, it is necessary to send the following commands as misalignment data. $PERDAPI,GYROALIGN,90,0,90*25 $PERDAPI,ACCELALIGN,90,0,90*6E

(i) (ΔθX, ΔθY, ΔθZ) = (+90, 0, +90)

Traveling

direction

+180°

This installation is that the rotate angle against X-axis is +180 degrees and the rotate angle against Z-axis is +180 degrees, which means that the heading of IMU sensor is +180 degrees at clockwise and the top side of IMU sensor faces downward. In this case, since ΔθX and ΔθZ is out of Auto Orientation range, it is necessary to send the following commands as misalignment data. $PERDAPI,GYROALIGN,180,0,180*25 $PERDAPI,ACCELALIGN,180,0,180*6E

(j) (ΔθX, ΔθY, ΔθZ) = (+180, 0, +180)

Figure 5.5 Installation Examples with Misalignment Command

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6 Calibration

Calibration is a function to estimate the output errors of IMU sensor and vehicle speed pulse. Estimated output errors are bias and gain. The bias is an output value when the input value is 0, and the gain is a ratio of the input value to the output value. Using the estimated bias and gain, the GNSS+DR receiver corrects the output value of IMU sensor and vehicle speed pulse, and outputs high precision position.

The calibration method is described in the following sections.

6.1 Power on to GNSS Position Fix

[Operation]

It is necessary to do position fix in open sky as a good GNSS signal reception environment

(*1)

before starting

calibration driving.

[Check]

1. Check the position fix status with GNS and RMC sentence Make sure that the position fix status is A or D.

Example:

Yellow high-light shows the position fix status (GNS sentence shows the position fix status of GPS, GLONASS and Galileo from left hand). $GNRMC,071201.776,A,3442.7276,N,13520.1229,E,0.00,30.96,130614,,,A,V*3C $GNGNS,071201.776,3442.7276,N,13520.1229,E,AAN,18,0.5,3.6,36.7,,,V*5C

2. Check the C/N0 value with GSV sentence The more number of satellites with C/N0 with over 40 dB-Hz, the better reception environment.

Example:

Yellow high-light shows the C/N0 value. $GPGSV,4,1,14,19,73,309,50,03,70,345,52,27,55,031,52,16,46,084,50,1*6A $GPGSV,4,2,14,07,40,307,52,11,39,211,49,08,19,320,46,01,15,199,40,1*61 $GPGSV,4,3,14,13,15,247,43,30,13,319,,22,11,090,46,23,05,219,42,1*6F $GPGSV,4,4,14,42,00,000,46,93,32,161,43,,,,,,,,,1*6F $GLGSV,2,1,07,82,71,317,56,80,67,326,53,79,50,152,52,81,30,031,55,1*7C $GLGSV,2,2,07,83,25,238,53,73,14,329,29,78,01,151,34,,,,,1*42

Notes:

(*1) As an index of a good GNSS signal reception environment, it is more than 50% of the number of satellites

in use with signal level of over 40 dB-Hz.

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6.2 GNSS Position Fix to DR Valid by Calibration Driving

[Operation]

Calibration function is available by driving with more than 20 km/h at open sky. Keep the vehicle speed of more than 20km/h at open sky. Otherwise calibration function may not work.

20Km/h overRun

Position status changes from GPS only to DR/GNSS mixed, which means that DR is valid, for a several minutes with this condition. While DR is valid, it is not equal to complete the calibration operation.

[Check]

a) Check the IMU result verified mode with PERDCRD,R sentence

When Field 3 is 1, DR is valid.

b) Check the DR use mode with PERDCRD,R sentence

When Field 4 is 2, DR/GNSS mixed (hybrid position fix status) is valid.

Example:

$PERDCRD,R,1,2,-0.68,-8.85,-0.01,-0.4,0.1,265.6,1,10*23

6.3 Calibration of Vehicle Speed Pulse and Accelerometer

[Operation]

Same as Section 6.2.

[Check]

Check the calibration status of vehicle speed pulse and accelerometer with the following sentences.

-Vehicle speed pulse:

When Field 3 is 7 or 15

(*1)

at PERDCRI,O sentence, the calibration of vehicle speed pulse is completed.

Example:

$PERDCRI,O,7,29,2,4.00,1.569858*10 $PERDCRI,O,15,0,0,4.02,1.569858*18

Notes:

(*1) In case of detecting reverse signal at status 7, the status becomes 15. It is necessary to check valid of

reverse signal before starting calibration of vehicle speed pulse.

-Accelerometer:

When Field 17 is 3 at PERDCRI,A sentence, the calibration of accelerometer is completed.

Example:

$PERDCRI,A,3,7,724,-701,-25,2572,2572,2572,689,-717,-22,88,44,0,3*19

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6.4 Calibration of Gyro Sensor

[Operation]

Calibration function of gyro sensor is available by driving with a several times (8 to 12 times) of right or left turn at GNSS or GNSS+DR status of open sky level. It is available to do mix calibration with Section 6.2 and 6.3.

Turn Left Turn Right

[Check]

When Field 17 is 5,7,13 or 15 at PERDCRI,G sentence, the calibration of gyro sensor is completed.

Example:

$PERDCRI,G,3,7,79,-8,-27,2601,2601,2601,79,-8,-27,88,44,0,7*1A

6.5 Aging and Temperature Fluctuations

Even after completion of calibration, the GNSS+DR receiver will continue to estimate bias and gain during actual operation. This is to follow changes in characteristics due to aging and temperature fluctuations.

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7 Operating of DR Backup

The GNSS+DR receiver has two kinds of backup source, which are the backup RAM and the Flash ROM. The backup data is stored into the backup RAM while a backup power is supplied to the GNSS+DR receiver. The GNSS+DR receiver can also store the backup data into the Flash ROM by sending PERDAPI,STOP,DRPARK command.

When the backup data is valid at the next operating, the GNSS+DR receiver outputs the position in DR only mode based on the backup data until GNSS position fix. When the GNSS+DR receiver receives GNSS signals and confirms the GNSS positioning result is correct, the position fix status changes to DR/GNSS mixed mode.

When changing the vehicle, installation angle and installation position of IMU sensor, the backup data should be deleted by sending PERDAPI,START,SIMCOLD command. And then, calibrate the IMU sensor parameters again.

8 Recommended NMEA Output Sentence at Customer Evaluation Stage

When evaluating the DR performance, it is recommended to collect PERDCRD, PERDCRI sentences and Diag data. It is very useful for analyzing the log data at FURUNO.

The recommended operating is as follow:

1. Send STOP command ($PERDAPI,STOP,DRPARK*5D).

2. Send output command ($PERDAPI,CROUT,DI*09) for output valid of PERDCRD and PERDCRI sentence.

3. Send Diag data output command ($PERDSYS,RECPLAY,ON*0B).

4. Send START command ($PERDAPI,START*37).

Notes:

When outputting the Diag data, it is necessary to change the baud rate to 460800 bps by the following command. $PERDCFG,UART1,460800*68 In case of using 460800 bps, taka care about UART communication error rate and do not use this baud rate except Diag data collection.

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9 Important Notice

9.1 Important Notice for IMU Sensor

Please design and implement based on the data sheet of IMU sensor. In addition, please verify the products to achieve the target performance.

9.2 Characteristics of IMU Sensor

The GNSS+DR receiver is designed to provide accurate performance by estimating errors of bias and gain described in the data sheet of IMU sensor. The performance may be degraded by influence of some characteristics not described in the data sheet of IMU sensor.

9.3 Layout Design against Influence of IMU Sensor by External Environment Factor

Since the IMU sensor is a very sensitivity device against the following three external environment factors, keep the layout design of IMU sensor based on the below guideline.

(1) Temperature factor External temperature has a negative impact on the angular velocity and the acceleration of IMU sensor. In order to avoid this influence, consider the following guideline of design.

a) Implement the IMU sensor apart from heat sources. b) Protect influences of dynamic temperature change by surrounding air.

(2) Mechanical factor The vibration and impulse against IMU sensor has a negative impact on the angular velocity and the acceleration of IMU sensor. Below are examples to avoid this influence.

a) Implement the IMU sensor nearby the holding part of the board. b) Clip the board by shock-absorbing material with labor. c) Fix the unit or board, which IMU sensor is implemented, by screws.

(3) Other factor Because of the gyro sensor and the accelerometer are MEMS devices, these devices have a resonant frequency for operating MEMS mechanically and electric frequency characteristics internally. In case the MEMS device has an external mechanical or electrical impact which is close to the frequency characteristics of MEMS device, there is a risk of significant degradation regarding the output characteristics of sensor. Therefore, user should design the circuit of surrounding area of sensor for preventing influences of external mechanical vibration or electrical signal characteristics such as system clock signal.

9.4 Calibrating Operation

Good GNSS signal reception environment provides suitable calibration of IMU sensor. Therefore, install the antenna on the place which good GNSS signals can be received. Also, take care that there is enough antenna gain and no degrade of reception signal by noise on actual operation.

For calibrating the vehicle speed pulse, it needs to drive faster than 20km/h under good GNSS signal reception environment. When an actual operation is traveling at a low-speed (ex. the bus drives in an urban area.), it needs much time for calibration or the calibration may not be finished. Therefore, it is recommended to start the actual operation after the calibration.

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9.5 Receiver Start Operation

The GNSS+DR receiver backs up the last updated position, the direction and the DR parameters. At the next power on, the GNSS+DR receiver starts the positioning in DR only mode by using the backup data. After that, when the direction calculated by DR is coincident with the GNSS direction, the position mode changes to DR/GNSS mixed mode. The GNSS+DR receiver outputs the positioning result by DR only until the position mode changes to the DR/GNSS mixed mode.

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10 FAQ

Q1. How do we check calibration completion status? A1. As a first step, please check “PERDCRD,R” sentence as DR valid. When Field 3 of this sentence is

indicated as “1”, DR mode is valid. The example of the sentence is as below. Example：$PERDCRD,R,1,2,-2.28,-12.12,0.16,-1.3,-0.5,260.5,3,17*17 Check this value is indicated as “1” As the next step, please check the following sentence status as calibration completion with calibration

driving. Calibration completion status of vehicle speed pulse:

Field 3 (odomtrConf) of PERDCRI,O is 7 or 15 Calibration completion status of accelerometer :

Field 17 (learnmode) of PERDCRI,A is 3 Calibration completion status of accelerometer :

Field 17 (learnmode) of PERDCRI,G is 5, 7, 13 or 15

Q2. The sensors do not become valid. A2. Please check if the gyro sensor and the accelerometer are installed in accordance with the direction

explained in the chapter 5. In case vehicle speed pulse is used, please confirm the vehicle speed pulse satisfies the electrical specifications and the count of vehicle speed pulse.

Q3. Is it possible to make DR positioning with gyro sensor only? A3. No, it is not. It is required to use vehicle speed pulse together with gyro sensor.

Q4. Is the reverse signal required when using vehicle speed pulse? A4. Yes.

Q5. How do we check the elevation pitch angle based on the sensor information? A5. Refer Field 9 (pitch) of PERDCRD,R sentence.

Q6. Does altitude data reflect on elevation pitch angle based on sensor information? A6. No. altitude data with GNS sentence does not reflect on elevation pitch angle.

Q7. In case we lost vehicle speed pulse with combination of gyro sensor, accelerometer and vehicle speed

pulse, what kind of behavior we observe.

A7. In case of non-vehicle speed pulse at first time, position fix status change to DR status by using

information of accelerometer as velocity source. In case of non-vehicle speed pulse on the way, user observes irregular ground tracking performance for a while until calibration reset. When user observes Field 11 (counts Status) of PERDCRD,R is 0, accelerometer is available as velocity source.

Q8. Do you have reference circuit regarding IMU sensor interface? A8. Please refer chapter 4.

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Q9. Is it possible to use other than vehicles? A9. No. The DR receiver is designed for car navigation systems and telematics terminals.

Q10. Not completed calibration of Gyro. A10. Please check whether there are more than the 50% of the number of satellites in use with signal level of

over 40dBHz signal level.

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