FURUNO GNSS Receiver. Dead Reckoning Solution User s Guide

Transcription

1 FURUNO GNSS Receiver erideopus 6/ erideopus 7 Model GV-8620/ GV-8720 Dead Reckoning Solution User s Guide (Document No. ) *The Dead Reckoning solution is exclusive for the BOSCH SMI130 sensor users.

2 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. FURUNO ELECTRIC CO., LTD. reserves the right to make changes to its products and specifications without notice. ou expressly acknowledge and agree that use of the "Application Note" is at your sole risk. This "Application Note" is provided 'AS IS' and without warranty of any kind and FURUNO expressly disclaims all other warranties, express or implied, including, but not limited to, the implied warranties of merchantability, fitness for a particular purpose and no infringement. FURUNO does not warrant that the functions contained in the "Application Note" will meet your requirements, or that the operation of the "Application Note" will be uninterrupted or error-free, or that defects in the "Application Note" will be corrected. Furthermore, FURUNO does not warrant or make any representations regarding the use or the results of the use of the "Application Note" in terms of their correctness, accuracy, reliability, or otherwise. No oral or written information or advice given by FURUNO authorized representative shall create a warranty or in any way increase the scope of this warranty. Without limiting the foregoing, FURUNO disclaims any and all express or implied warranties of any kind, and you expressly assume all liabilities and risks, for use or operation of the "Application Note", including without limitation. Should the "Application Note" prove defective, you assume the entire cost of all necessary servicing, repair or correction. Some jurisdictions do not allow the exclusion of implied warranties, so the above exclusion may not apply to you. All brand and product names are registered trademarks, trademarks or service marks of their respective holders.

3 Revision History Revision Description Date 0 Initial release Chapter 1 Corrected the available software version. Section 3.1 Changed the supported IMU sensor Section 4.2~4.7 Removed. Table 5.1, 5.2 Removed the sensor combination. 2 Updated the cover page

4 Table of Contents 1 General Description 1 2 FURUNO DR GNSS Receiver 1 3 System Configuration Supported Sensor Sensor Interface Configuration 3 4 Reference Circuit SMI IMU Sensor Installation Automatic Correction by Auto Orientation Function Expand Auto Orientation Range by PERDAPI,AUTOORIENT Command Set Installation Angle by Misalignment Sensor Installation Examples ero Angle against Axis of IMU Sensor Auto Orientation Default Range Auto Orientation Expansion Range Out of Auto Orientation Range 11 6 Calibration Power on to GNSS Position Fix GNSS Position Fix to DR Valid by Calibration Driving Calibration of Vehicle Speed Pulse and Accelerometer Calibration of Gyro Sensor Aging and Temperature Fluctuations 14 7 Operating of DR Backup 15 8 Recommended NMEA Output Sentence at Customer Evaluation Stage 15 9 Important Notice Important Notice for IMU Sensor Characteristics of IMU Sensor Layout Design against Influence of IMU Sensor by External Environment Factor Calibrating Operation Receiver Start Operation FAQ 18

5 1 General Description This document describes user s guide for achieving best performance of FURUNO Dead Reckoning (DR) GNSS receiver (DR receiver). - erideopus 6 (P/N: epv6010b) Dead Reckoning Chip solution - erideopus 7 (P/N: epv7010b) Dead Reckoning Chip solution - GV GV-8620 Available software: As from ENP6.53A The 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 The 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) 1

6 3 System Configuration 3.1 Supported Sensor Table 3.1 shows FURUNO supported IMU sensor. Please design optimized system on customer platform with the IMU sensor, the vehicle speed pulse and the vehicle reverse signal (*1). Table 3.1 Supported IMU Sensor (*2) Product number Vendor # of axis Automotive SMI130 Bosch 6 Notes: (*1) Specification of vehicle speed pulse and reverse signal Please check the regulation and electric characteristics by 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 The DR receiver satisfies the DR performance with the appropriate calibration described in Chapter 6 using the IMU sensor. 2

7 3.2 Sensor Interface Configuration Figure 3.1shows I/O relation between the DR receiver and the supported sensor in Table 3.1. Sensor information I/O signal Pin # epv6010b / epv7010b GV-86/ GV-87 I2C serial clock Gyro/Accelerometer (SCL) TD2_SCL F8 #19 combo sensor I2C serial data (SDA) RD2_SDA G8 #18 Vehicle speed pulse ECNT C7 #7 Reverse signal GPIO E6 #1 FURUNO Dead Reckoning GNSS Receiver UART1 TD1 RD1 Output data (Position, Time, Sensor status, ) Command data (NMEA setting, Mis-alignment, ) I2C TD2_SCL RD2_SDA I2C serial clock from sensor block I2C serial address and data between sensor block ECNT Vehicle speed pulse GPIO Reverse signal Figure 3.1 Sensor Interface Configuration Block Level Diagram 3

8 16 INT1 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 (TD2_SCL, RD2_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 VCC (*2) (*3) (*3) R1 R2 10k 10k (*1) SCL (*1) SDA VCC (*2) U1 SCK 8 VCC (*2) C2 0.1uF PS GNDIO CSB2 GND VDD NC INT2 9 SDI 10 SDO2 VDDIO INT3 13 INT4 14 CSB1 15 SDO1 C1 0.1uF SMI130 I/O signal Description Interface connection destination erideopus 6/7 GV-86/ 87 SCL I2C clock TD2_SCL TD2_SCL SDA I2C address/data bus RD2_SDA RD2_SDA Figure 4.1 Reference Circuit of SMI130 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

9 5 IMU Sensor Installation For the installation of the IMU sensor, the DR receiver has specification values for the inclination and the deviation of the coordinate system of the vehicle and the IMU sensor. The 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. <Definition of coordinate system and axis> Here are definitions of axis against sensor unit installation angle: - Direction of forward movement: -axis - Horizontal to the direction of movement: -axis - Vertical to the direction of movement: -axis Rotation angles to the each axis are defined as follows: - Rotation angle around the axis: Δθ Roll angle - Rotation angle around the axis: Δθ Pitch angle - Rotation angle around the axis: Δθ aw angle Figure 5.1 (a) to (d) shows inclination against each axis. Surface 0 0 Δθ Direction of movement (a) No inclination (b) Inclines Δθ to the direction of movement 0 0 Δθ Δθ (c) Inclines Δθ to the horizontal direction (d) Inclines Δθ to the height direction Figure 5.1 Sensor Unit Installation Angle Definition 5

10 When the axis described in the IMU sensor data sheet defines the -axis and the -axis opposite to the DR receiver axis definition, the DR receiver changes the -axis and -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 allowable angle range in which the Auto Orientation operates. Table 5.1 Functional Range of Auto Orientation (Default) Δθ Δθ Δθ Notes aw angle Roll angle Pitch angle ±15 ±60 ± Expand Auto Orientation Range by PERDAPI,AUTOORIENT Command 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) Δθ Δθ Δθ Notes aw angle Roll angle Pitch angle ±15 ±15 ±75 Pitch angle expansion ±180 ±45 Roll angle expansion 6

11 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,GROALIGN, 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 DR receiver with vehicle stop condition. 4. Send $PERDAPI,STOP,DRPARK*5D command and stop normal operating of DR receiver. 5. Send delta angle by misalignment set command. (Gyro sensor misalignment command) $PERDAPI,GROALIGN,Δθx,Δθy,Δθz*hh (Accelerometer sensor misalignment command) $PERDAPI,ACCELALIGN,Δθx,Δθy,Δθz*hh *Setting sequence of misalignment angle against absolute axis is Δθ -> Δθ -> Δθ. 6. Send $PERDAPI,START,SIMCOLD*48 command and initiate normal operating 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. 7

12 5.4 Sensor Installation Examples Here are sensor, which is 3-axis gyro and 3-axis accelerometer, installation examples with the DR receiver evaluation kit (VN-871 or VN-861) ero Angle against Axis of IMU Sensor This installation is ideal, which means that this installation angle meets requirement specifications of IMU sensor based on data sheet. Traveling direction O (a) (Δθ, Δθ, Δθ ) = (0, 0, 0) Figure 5.2 ero Angle against Axis of IMU Sensor 8

13 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 -axis is +15 degrees, which means that heading of IMU sensor is -15 degrees at clockwise against traveling direction. O (b) (Δθ, Δθ, Δθ ) = (0, 0, +15) This installation is that the rotate angle against -axis is -15 degrees, which means that horizontal plane of IMU sensor is -15 degrees at counter clockwise against -axis. Traveling direction O -15 (c) (Δθ, Δθ, Δθ ) = (-15, 0, 0) Traveling direction +30 O This installation is that the rotate angle against -axis is +30 degrees, which means that elevation angle of IMU sensor is +30 degrees against traveling direction. (d) (Δθ, Δθ, Δθ ) = (0, +30, 0) Figure 5.3 Installation Examples within Auto Orientation Default Range 9

14 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. This installation is that the rotate angle against -axis is +75 degrees, which means that elevation angle of IMU sensor is +75 degrees against traveling direction. Traveling direction +75 O (e) (Δθ, Δθ, Δθ ) = (0, +75, 0) This installation is that the rotate angle against -axis is +180 degrees, which means that the top side of IMU sensor faces downward. Traveling direction O +180 (f) (Δθ, Δθ, Δθ ) = (+180, 0, 0) Traveling direction +45 O +180 This installation is that the rotate angle against -axis is +180 degrees and against -axis is +45 degrees, which means that the top side of IMU sensor faces downward and the elevation angle inclines +45 degrees. (g) (Δθ, Δθ, Δθ ) = (+180, +45, 0) Figure 5.4 Installation Examples within Auto Orientation Expansion Range 10

15 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 O This installation is that the rotate angle against -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 -axis is +30 degrees), since Δθ is out of Auto Orientation range, it is necessary to send the following commands as misalignment data. $PERDAPI,GROALIGN,0,0,30*16 $PERDAPI,ACCELALIGN,0,0,30*5D (h) (Δθ, Δθ, Δθ ) = (0, 0, +30) Traveling direction O This installation is that the rotate angle against -axis is +90 degrees and the rotate angle against -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 Δθ is out of Auto Orientation range, it is necessary to send the following commands as misalignment data. $PERDAPI,GROALIGN,90,0,90*25 $PERDAPI,ACCELALIGN,90,0,90*6E Traveling direction +180 O +180 (i) (Δθ, Δθ, Δθ ) = (+90, 0, +90) This installation is that the rotate angle against -axis is +180 degrees and the rotate angle against -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 Δθ and Δθ is out of Auto Orientation range, it is necessary to send the following commands as misalignment data. $PERDAPI,GROALIGN,180,0,180*25 $PERDAPI,ACCELALIGN,180,0,180*6E (j) (Δθ, Δθ, Δθ ) = (+180, 0, +180) Figure 5.5 Installation Examples with Misalignment Command 11

16 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 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: ellow high-light shows the position fix status (GNS sentence shows the position fix status of GPS, GLONASS and Galileo from left hand). $GNRMC, ,A, ,N, ,E,0.00,30.96,130614,,,A,V*3C $GNGNS, , ,N, ,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: ellow 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. 12

17 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. Run 20Km/h over 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* 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, *10 $PERDCRI,O,15,0,0,4.02, *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 13

18 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 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. 14

19 7 Operating of DR Backup The 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 DR receiver. The 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 DR receiver outputs the position in DR only mode based on the backup data until GNSS position fix. When the 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 ($PERDSS,RECPLA,ON*0B). 4. Send START command ($PERDAPI,START*37). Notes: When outputting the Diag data, it is necessary to change the baud rate to bps by the following command. $PERDCFG,UART1,460800*68 In case of using bps, taka care about UART communication error rate and do not use this baud rate except Diag data collection. 15

20 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 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. 16

21 9.5 Receiver Start Operation The DR receiver backs up the last updated position, the direction and the DR parameters. At the next power on, the 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 DR receiver outputs the positioning result by DR only until the position mode changes to the DR/GNSS mixed mode. 17

22 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. es. 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. 18

23 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. 19