FURUNO GNSS Receiver

Transcription

1 FURUNO GNSS Receiver Model: GN-8620 (Document No. )

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. All rights reserved. Any information of this documentation shall not be disclosed to any third party without 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. All brand and product names are registered trademarks, trademarks or service marks of their respective holders. The following satellite systems are operated and controlled by the authorities of each government. - GPS(USA) - Galileo(Europe) - QZSS(Japan) - SBAS(USA: WASS, Europe: EGNOS, Japan: MSAS, India: GAGAN) FURUNO is not liable for any degradation while using these satellite systems. FURUNO cannot guarantee specifications if any of these systems experience degradation. Based on these conditions the user is expected to be familiar with these systems and is fully responsible for their use.

3 Revision History Version Changed contents Date 0 Initial release

4 Table of Contents 1 Outline 1 2 Approval Software Version 1 3 Communication Specification 1 4 NMEA Sentence Format Standard Sentence Proprietary Sentence 3 5 State Specifications 4 6 Backup Data 8 7 Transmission and Reception Sequence Startup Sequence Sequence from Fix Session OFF to Fix Session Periodical Output Sentence Receiver Configuration Setting Sequence Receiver Data Output Request Backup Data Input/Output Backup Data Output Request Sequence Backup Data Input Sequence Serial Communication Format Configuration Time Setting Position Setting ESIPLIST New ESIPLIST Create ESIPLIST Append ESIPLIST Query ESIPLIST Delete ESIPLIST Configurable Command ESIPLIST Executing Condition with EXECUTE command in ESIPLIST Fix Session OFF Sequence Power OFF Sequence Flash ROM Reprogramming 30 8 Receiving NMEA Sentence Receiving Data Cutout from String Cutout from Strings in Fixed Interval Cutout from Every Strings TalkerID Satellite No Time in NMEA Sentence Delta between Current Time and Position Fix Time Position Fix Status Position Fix State Becomes Valid While No Position Fix Direction 32 9 Exception Process Exception Operation Recovery Process Function Exclusion Standard NMEA Output GBS GNSS Satellite Fault Detection GFA GNSS Fix Accuracy and Integrity GGA Global Positioning System Fix Data GLL Geographic Position - Latitude/Longitude GNS GNSS Fix Data GSA GNSS DOP and Active Satellites GST GNSS Pseudo Range Error Statistics GSV Satellites in View RMC Recommended Minimum Navigation Information 44

5 11.10 VTG Course Over Ground and Ground Speed ZDA Time & Date Proprietary NMEA Input API eride GNSS Core Library Interface CROUT Original Sentence Output DATUM Geodetic Datum DEFLS Default Leap Second EXTENDGSA GSA Re-definition FIRSTFIXFILTER First Fix Filter Parameters FIXMASK Mask Configuration FIXPERSEC Multiple Fixes Per Second GNSS GNSS Configuration LATPROP Latency Position Propagation OUTPROP Position Outage Propagation PIN Static Pinning POS Position Aiding PPS PPS (Pulse Per Second) RAIM RAIM Function RESTART/RESTARTNOFPR Stop and Start the GNSS Core Library SBASBLS SBAS Search Select SELFEPH Self-Ephemeris TM START Start the GNSS Core Library STATIC Static Entry/Exit Parameters STOP/STOPNOFPR Stop the GNSS Core TIME Time Aiding CFG Application Software Configuration ESIPLIST Save ESIP Command to FLASH FACTORYRESET Clear Non-Volatile Memory FORMAT Protocol Format NMEAOUT Configure the Standard NMEA Outputs SILENTSTART SILENTSTART Mode Setting UART1 Configure Serial Communications UART2 Configure Serial Communications SYS Control/Query the PVT System ANTSEL Antenna Selection Control BBRAM BBRAM Query Command 62 BBRAM Push Strings ERRACT Receiver s State Processing at Exception Operation FIXSESSION GNSS Session Query GPIO General Purpose Input/Output RECPLAY Diagnostics Mode SELFEPH Self-Ephemeris TM Models Calculation SELFTEST Self-Test Request VERSION Software Version Information Proprietary NMEA Output ACK Command Acknowledgement CFG Response to PERDCRG Input Commands ADDON ESIPLIST CRx Core Library GNSS Strings CRE Ephemeris Data CRF GNSS Accuracy and GNSS Health CRF,GxACC GNSS Accuracy 69 CRF,GxANC GNSS Health CRL LTCSM / Self-Ephemeris TM Data CRP PPS Status CRQ Galileo SAR/RLM Data MSG Event Driven Messages RPx Diagnostic Output Data 75

6 13.6 SYS PERDSYS Output Commands ANTSEL Antenna Selection Control Output BBRAM Backup Data Output FIXSESSION GNSS Fix Session State Information GPIO General Purpose Input/Output SELFEPH Self-Ephemeris TM Calculation State SELFTEST Self-Test Output VBKERR VBK Error Report VERSION Software Version Information RTCM Correction Data Configuration Diagram RTCM Message Usage 83

7 1 Outline GN-8620 This document describes the eride Serial communications Interface Protocol (esip) for controlling GN Approval Software Version This document applies to GN The associated Platform software version is ENP6.51A and newer. 3 Communication Specification Table 3.1 shows the communication interface of the esip protocol. Table 3.1 Communication Interface NMEA Protocol (esip) RTCM SC-104 (Input Only) Communication Port UART1 (TXD1, RXD1) UART2 (RXD2) Communication Type Asynchronous full duplex communication method (no control sequence) Baud rate [bps] Deviation error [%] Baud rate [bps] Deviation error [%] 4, ,800 (Default) ,600 (Default) , Transfer Rate 1 19, , , , , , , , , , Data Length 1 8 bit Stop Bit 1 1 bit Parity 1 None Output Rate 1000 ms (1 Hz) (Default) ms (2 Hz) 200 ms (5 Hz) 100 ms (10 Hz) - Character Code NMEA-0183 Ver data based RTCM SC-104 (Ver. 2.3) 5 6 ASCII code 4 Protocol Contents Input Data NMEA Proprietary Sentence Output Data NMEA Standard Sentence NMEA Proprietary Sentence Input Data Message Type 1 Message Type 3 Message Type 9 1 These setting can be changed. Please refer to Section for details. 2 To set multi-gnss setting, it is required to set the transfer rate to bps or higher. 3 These setting can be changed. Please refer to Section for details. 4 NMEA 0183 STANDARD FOR INTERFACING MARINE ELECTRONIC DEVICES Version 4.10 (NATIONAL MARINE ELECTRONICS ASSOCIATION, June, 2012) 5 RTCM RECOMMENDED STANDARDS FOR DIFFERENTIAL NAVSTAR GPS SERVICE Version 2.3 (DEVELOPED BY RTCM SPECIAL COMMITTEE NO.104, August 20, 2001) 6 This code is the standard code for the differential GPS correction data. 1

8 4 NMEA Sentence Format GN-8620 NMEA format has two kinds of sentence which is standard and proprietary sentence. All letters in the sentences which is included checksum are capital letters. Data in backup RAM area by calling PERDSYS,BBRAM command from the host processor includes small letters. 4.1 Standard Sentence $ <Address field>, <Data field> *<Checksum field> <CR> <LF> 5 bytes "$" Start-of-Sentence marker <Address field> 5-byte fixed length. First 2 bytes represent a talker ID, and the remaining 3 bytes do a sentence formatter. The talker IDs are GN of GNSS, GP for GPS, GL for GLONASS and GA for Galileo. Table 4.1 shows the talker ID of standard NMEA sentences. Talker IDs are changed by PERDAPI,GNSS command setting and used satellite systems. Table 4.1 Standard NMEA Sentence Talker ID Standard NMEA Sentence Talker ID Configuration AUTO GN LEGACYGP RMC Recommended Minimum Navigation Information GN/GP/GA 7 GN GP GNS GNSS Fix Data GN/GP/GA 7 GN GP GGA Global Positioning System Fix Data GN/GP/GA 7 GN GP GLL Geographic Position - Latitude/Longitude GN/GP/GA 7 GN GP VTG Course Over Ground and Ground Speed GN/GP/GA 7 GN GP GST GNSS Pseudo Range Error Statistics GN/GP/GA 7 GN GP GBS GNSS Satellite Fault Detection GN/GP/GA 7 GN GP GFA Integrity Data GN/GP/GA 7 GN GP GSA GPS DOP and Active Satellites GN/GP/GA 7 GN/GP/GA 7 GP ZDA Time & Date GN/GP/GA 7 GN GP Satellites in View (GPS, SBAS, QZSS) GP 8 GP GP GSV Satellites in View (GLONASS) GL 9 GL - Satellites in View (Galileo) GA 10 GA x 11 <Data field> Basically, they are variable-length fields and are delimited by delimiter "," (comma). The valid data character set is all characters from ASCII 0x20-0x7D, except "!" (0x21), "$" (0x24), "*" (0x2A), " " (0x5C), and "^" (0x5E). When there are not applicable data, they were expressed in null field. The fields inside [ ] are optional fields. <Checksum field> 8 bits data between "$" and "*" (excluding "$" and "*") are XORed, and the resultant value is converted to 2 bytes of hexadecimal letters. 7 GN/GP/GA changes depending on the using satellite system. - GN: No fix, or both GPS (including SBAS and QZSS) and Galileo are used in positin fix. - GP: Only GPS (including SBAS and QZSS) is used in position fix. - GA: Only Galileo is used in position fix. 8 GPGSV is output in the following cases: - The receiver has the GPS satellite information (including SBAS and QZSS) and is set to 1 to 3 by PERDAPI,GNSS command - No position fix 9 GLGSV is output in case of no position fix. 10 GAGSV is output in the following cases: - Galileo is used in position fix - No position fix. 11 The satellite system is valid for positioning but the sentence is not output. 2

9 <CR><LF> End-of-Sentence marker - <CR>: 0x0D - <LF>: 0x0A 4.2 Proprietary Sentence $ P <maker code> <Sentence type>, <Data field> *<Checksum field> <CR> <LF> "$" Start-of-Sentence marker "P" Proprietary Sentence ID 3 bytes 3 bytes <Maker code> It indicates the maker and it is "ERD". <Sentence type> It indicates the type of sentence with the following classes. - API - CFG - SYS Table 4.2 shows the relation between the command categories and the default events. Table 4.2 Relations between Command Categories and Default Events Command category Default event $PERDAPI $PERDCFG $PERDSYS Power ON/OFF Hardware reset PERDAPI,STOP/STOPNOFPR - - PERDCFG,FACTORYRESET - - : Return to the default setting <Data field> Basically, they are variable-length fields and are delimited by delimiter "," (comma). The valid data character set is all characters from ASCII 0x20-0x7D, except "!" (0x21), "$" (0x24), "*" (0x2A), " " (0x5C), and "^" (0x5E). When there are not applicable data, they were expressed in null field. The fields inside [ ] are optional fields. <Checksum field> 8 bits data between "$" and "*" (excluding "$" and "*") are XORed, and the resultant value is converted to 2 bytes of hexadecimal letters. <CR><LF> End-of-Sentence marker - <CR>: 0x0D - <LF>: 0x0A 3

10 5 State Specifications GN-8620 Figure 5.1 shows a state diagram of the receiver. Whenever the user operates the following process, the user should set the receiver to Fix session off (S3): - Load program in Flash ROM - Registry ESIPLIST in Flash ROM - Read/Write access to backup data in backup RAM T51 Flash ROM program loading S5 T35 T31 Power off S1 T63 Fix session off S3 T13 T23 T21 T12 Activating BBRAM S6 T36 T43 T34 T32 Fix session on S2 Writing ESIPLIST data S4 Table 5.1 shows explanations about each state. Figure 5.1 State Diagram State Power off Fix session on Fix session off Activationg BBDATA Flash ROM program loading Writing ESIPLIST data Table 5.1 Receiver s State Description Invalid all function Activating normal position fix process Normal position fix process halt Not available UART port Bidirectional access session between the host processor and the receiver about backup data in RAM area data Programming session about program data in Flash ROM between the host processor and the receiver Bidrectional access session between the host processor and the receiver about ESIPLIST data in Flash ROM 4

11 Table 5.2 shows events of each state transaction. State transaction Table 5.2 Event of Each State Transaction Event Notes T12 Power on - T13 Power on in SILENTSTART mode It is required to register PERDCFG,SILENTSTART command into ESIPLIST. T21 T31 T51 Power off Input the following command - PERDAPI,STOP T23 - PERDAPI,STOPNOFPR Detect a self-test error or an error status It is required to set PERDSYS,ERRACT command to HALT. T32 T34 T43 T36 T35 T63 Input the following command - PERDAPI,START Input the following command - PERDCFG,ESIPLIST,NEW - PERDCFG,ESIPLIST,APPEND Input the following command - PERDCFG,ESIPLIST,CLOSE Input the following command - PERDSYS,BBRAM Complete session sequence between the host processor and the receiver. Host processor can check that fix session state is available by reception of PERDACK and PERDSYS,FIXSESSION,ON sentences. Refer to "Flash ROM Programming Procedures with WinUppg" (Doc # SE ) about Flash ROM program rewriting. Table 5.3 shows the relation between the standard NMEA sentences and Fix session. Table 5.3 Standard NMEA Sentence Output Condition Output sentence Description Fix session on Fix session off RMC Recommended minimum navigation information - GNS GNSS fix data - GGA Global positioning system fix data - GLL Geographic position latitude/longitude - VTG Course over ground and ground speed - GST GNSS pseudo range error statistics - GBS GNSS satellite fault detection - GFA Integrity data - GSA DOP and active satellites - ZDA Time and date - GSV Satellites in view - : Output is available. It is possible to control output function (ON/OFF) and output period by PERDCFG,NMEAOUT command. -: Output is not available. 5

12 Table 5.4 shows the relation between input condition of proprietary NMEA and Fix session. Input command Table 5.4 Proprietary NMEA Input Condition Description 6 GN-8620 Fix session on Fix session off PERDAPI CROUT Original sentence output I I DATUM Geodetic datum I I DEFLS Default leap second I 12 / q I / q EXTENDGSA GSA sentence re-definition I I FIRSTFIXFILTER First fix filter parameters I I FIXMASK Satellite mask I I FIXPERSEC Multiple fixes per second I 12 I GNSS GNSS configuration I I LATPROP Enable latency position propagation I I OUTPROP Enable position outage propagation I I PIN Static pinning I I POS Position aiding I I PPS PPS (Pulse per second) I I RAIM RAIM I I RESTART/ RESTARTNOFPR Restart request I I SBASBLS SBAS priority search select I I SELFEPH Self-Ephemeris TM mode ON/OFF I I START Start request NACK I STATIC Static entry/exit parameters I I STOP/STOPNOFPR Stop request I NACK TIME Time aiding I I PERDCFG ESIPLIST Save/query ESIP commands to FLASH q I / q FACTORYRESET Clear backup data in Backup RAM and Flash ROM NACK I FORMAT Protocol format I 12 I NMEAOUT Configure the standard NMEA outputs I I SILENTSTART SILENTSTART mode E E UART1/UART2 Serial communication port configuration I 12 I PERDSYS ANTSEL Antenna selection control I / q I / q BBRAM Backup data output query q 13 q Backup data input NACK I ERRACT Receiver s state processing at exception operation I I FIXSESSION GNSS session query I / q I / q GPIO GPIO output query q q RECPLAY Diagnostic mode ON/OFF I 12 I SELFEPH Self-Ephemeris TM calculation I I SELFTEST Self-test q q VERSION Software version query q q I: Input is available. q: Query is available. NACK: Not related to internal process. E: Use the command by ESIPLIST. 12 Input this command at fix session off state. 13 Request to output the backup data at fix session off state to avoid mix transmission with the backup data and the other data.

13 Table 5.5 shows the relation between output condition of proprietary NMEA and Fix session. Table 5.5 Proprietary NMEA Output Condition Output sentence Description Fix session on Fix session off PERDACK ACK Command acknowledgement A A PERDCFG ADDON Startup status S - ESIPLIST ESIP command query into ESIPLIST Q Q PERDCRx CRE GNSS ephemeris data O - CRF,GxACC GNSS accuracy O - CRF,GxANC GNSS health O - CRL LTCSM / Self-Ephemeris TM availability O - CRP PPS status O - CRQ Galileo SAR/RLM data O - PERMSG MSG Event message E E PERDRPx RPx Diagnostic data O - PERDSYS ANTSEL Antenna selection control status S / Q Q BBRAM Backup data output Q 14 Q FIXSESSION GNSS session Q / R / S / E Q GPIO GPIO status Q Q SELFEPH Self-Ephemeris TM calculation state E E SELFTEST Self-test Q Q VBKERR VBK error report E E VERSION Software version S / Q Q A: Output as ACK or NACK for input command E: Output when certain events occur O: Output is available Q: Output when the query command is input R: Output at the following conditions: - The state transfers from fix session off state to fix session state by PERDAPI,START command. - The state transfers from fix session state to fix session off state by PERDAPI,STOP or PERDAPI,STOPNOFPRcommand. S: Output at power on. -: Output is not available. 14 Output the backup data at fixsession off state to avoid mix transmission with the backup data and the other data. 7

14 6 Backup Data GN-8620 The receiver backs up the last updated position, the last updated time, the ephemeris, the almanac, the CSM, the LTCSM and the Self-Ephemeris TM. These backup data are used for shortening the position fix time at the next start-up. Because the data from (1) to (5) of below are saved into the backup RAM, they are continued to save whiling a backup power is supplied to the receiver. The receiver can also save them into the Flash ROM when PERDAPI,STOP command is sent. Data (6) and (7) of below are saved into the Flash ROM area. (1) Last updated position This data shows the last position data calculated by the receiver. It shows the position data in GGA, GLL, GNS and RMC sentence. This data is backed up every position fix. (2) Last updated time This data shows the last UTC calculated by the receiver and the RTC counter value. It shows the UTC data in GGA, GLL, GNS and RMC sentence.this data is backed up after fixing the time at first. When the receiver s state is power off state and a backup power is supplied to the receiver, the time at power on can be calculated from the delta between the last updated time and the RTC counter value. This document defines the time calculated the delta between the last updated time and the RTC counter value as RTC time. The RTC time is valid when the receiver can calculate it and the RTC time is invalid when the receiver cannot calculate it because the backup power is not supplied. (3) Ephemeris These data show the ephemeris data broadcasted from GNSS satellites. These are backed up, when the receiver obtains and updates them. (4) Almanac These data show the almanac data broadcasted from GNSS satellites. These are backed up, when the receiver obtains and updates them. (5) CSM These data shows the all GPS satellites ephemeris model downloaded from an assist server (These are FURUNO original format). These are backed up into the backup RAM at downloading the data. (6) LTCSM These data shows the extend satellites ephemeris model downloaded from an assist server (These are FURUNO original format). These are backed up into the Flash ROM area at downloading the data. (7) Self-Ephemeris TM These data shows the extended ephemeris model made from received satellites ephemeris. The time is max three days. These are backed up into the Flash ROM area at downloading the datal. 8

15 7 Transmission and Reception Sequence GN-8620 This chapter shows the transmission and reception sequences between the receiver and the host system. The receiver outputs the response sentence ($PERDACK...) or the requested data when the commands written in the chapter 12 are input. If the receiver does not return a response though the correct command is input, an error may be occurred on transmitting line. Please input the command again. 7.1 Startup Sequence The receiver outputs the version message ($PERDSYS,VERSION ), the configuration data 1) and the fix session start message ($PERDSYS,FIXSESSION,ON) and do start process soon after power on. Until finishing the inintial process, the receiver is not able to receive input commands. It takes max 600 milliseconds as maximum inhibition reception time for host processor to be able to input the command. Figure 7.1 shows the session sequence from power on to command input available. Start-up process (600 msec) Receiver Power on $PERDSYS,VERSION... : Software version output 1) $PERDSYS,FIXSESSION,ON :Fix session start Host system Fix session (Input available) Figure 7.1 Session Sequence from Power on to Command Input Available Notes: 1) The configuration data are below (In case that LNA setting is High Gain mode). $PERDSYS,ANTSEL,FORCE1H,1HIGH*6C $PERDCFG,CUSTOM,GN8687*5A $PERDCFG,ADDON,N/A,BASIC*57 $PERDSYS,VBKERR,OK*44 $PERDSYS,FIXSESSION,INIT*49 9

16 7.2 Sequence from Fix Session OFF to Fix Session Figure 7.2 shows the transition sequence from fix session off state to fix session state. The receiver's state will change to fix session state after PERDACK sentence and PERDSYS,FIXSESSION,ON sentence are output, when PERDAPI,START command is input at the fix session off state. Receiver Host System $PERDAPI,START : Start Request Fix Session OFF $PERDACK,PERDAPI : Acknowledge (START) $PERDSYS,FIXSESSION,ON :Fix Session Start Fix Session (Input Enable) Figure 7.2 Session Sequence from Fix Session OFF to Fix Session 10

17 7.3 Periodical Output Sentence Figure 7.3 shows the periodical output sequence when the following NMEA sentences are output synchronized with positioning interval which is 1Hz. (Output NMEA sentences) RMC, GNS, GST, GSA, ZDA and GSV (Talker ID other than GSV are GN and Talker ID for GSV is GP.) Receiver Host System A (*1) 1000 msec B (*1) $GNRMC $GNGNS $GNGST $GNGSA $GNZDA $GPGSV A (*1) D (*1) C (*1) 1000 msec B (*1) $GNRMC $GNGNS $GNGST $GNGSA $GNZDA $GPGSV C (*1) D (*1) (*1) A: Fix Computation Process B: Output Process C: Input Process D: Other Process Figure 7.3 Session Sequence of Periodical NMEA Output Sentence 11

18 7.4 Receiver Configuration Setting Sequence Figure 7.4shows the session sequence for the receiver which is update rate 1Hz and output positioning data synchronized with positioning cycle of RMC, GNS and GSV sentences when the receiver setting is changed by sending the following commands. - PERDAPI,FIXMASK command - PERDAPI,PIN command The following figure shows the difference in response time which is a response of each input of command by input timing and the time which is reflected to positioning results against input command setting by input timing. Receiver Host System A (*1) $PERDAPI,FIXMASK 1000 msec D (*1) C (*1) B (*1) $GNRMC $GNGNS $GPGSV $PERDACK,PERDAPI Acknowledge (FIXMASK) $PERDAPI,PIN FIXMASK Reply Time FIXMASK Process Time 1000 msec A (*1) B (*1) C (*1) $GNRMC $GNGNS $GPGSV (reflected FIXMASK) $PERDACK,PERDAPI Acknowledge (PIN) PIN Reply Time PIN Process Time D (*1) 1000 msec A (*1) B (*1) $GNRMC $GNGNS $GPGSV (reflected PIN) C (*1) D (*1) (*1) A: Fix Computation Process B: Output Process C: Input Process D: Other Process Figure 7.4 Session Sequence Example in Case of Changing Receiver Setting (1 Hz) 12

19 1. Maximum response time from data input to data output The receiver needs maximum 1000 milliseconds to output the requested data since the data output request command which is input just behind input processing will be accepted at the next input processing of completion of positioning calculation processing and output processing when the receiver is in the fix session state and the update rate 1Hz. Table 7.1 shows the maximum response time from data input to data output for each state and each update rate. Table 7.1 Maximum Response Time from Data Input to Data Output State Update rate [Hz] Maximum response time [msec] Fix session Fix session off Maximum response time from setting data input to positioning data output The receiver needs maximum 2000 milliseconds to output the positioning data which is reflected the setting data input by sending commands when the receiver is in the fix session state and the update rate 1Hz. Table 7.2 shows the maximum response time to output the positioning data after the input of setting data for each update rate. Table 7.2 Maximum Response Time from Setting Data Input to Positioning Data Output State Update rate [Hz] Maximum response time [msec] Fix session Number of commands which is able to input at one time The receiver can accept an input command once per second in principal. The receiver can accept multiple input commands per one second when it has a low load depending on the receiver setting and the positioning status. 20 commands can be input to the receiver in a row when the receiver is in the fix session off state. It is able to input the next command at the timing of finishing the output of receiver response against the command group which are input first. 13

20 7.5 Receiver Data Output Request The following is the sequence when the host processor requests the receiver data output request. Figure 7.5 shows the sequence from input of PERDSYS,GPIO command and PERDSYS,VERSION command to the receiver 1Hz positioning to output the requested data. Receiver Host System 1000 msec A (*1) B (*1) $PERDSYS,GPIO :GPIO Output Request $GNRMC $GNGNS $GPGSV $PERDSYS,GPIO:GPIO Data D (*1) C (*1) $PERDSYS,VERSION :Software Version Request 1000 msec D (*1) C (*1) B (*1) A (*1) $GNRMC $GNGNS $GPGSV $PERDSYS,VERSION : Software Version Reply (*1) A: Fix Computation Process B: Output Process C: Input Process D: Other Process Figure 7.5 Session Sequence Example in Case of Requesting Receiver Output Data (1 Hz) 1. Maximum response time to output requested data after input of receiver data output request The receiver needs maximum 1000 milliseconds to output the requested data by sending a command since the data output request command which is input just behind input processing will be accepted at the next input processing of completion of positioning calculation processing and output processing when the receiver is in the fix session state and the update rate 1Hz. Table 7.3 shows the maximum response time to output the requested data after the input of data output request command for each state and each update rate. Table 7.3 Maximum Response Time to Output Requested Receiver Data State Update rate [Hz] Maximum response time [msec] Fix session Fix session off

21 7.6 Backup Data Input/Output Here is the explanation of sequence to output and to input the receiver backup data in the MULTIB64 format and the ESIP64 format. Since the capacity of backup data exceeds a transmission capacity in one sentence, the backup data is divided when the backup data is output or input. Figure 7.6 shows the outline of process of backup data input/output. The data is divided by the receiver. GNSS Receiver Divided data 1 Sequence No.1 Divided data 2 Sequence No.2 Output Backup Data (Backup RAM) Divided data 3 Sequence No.3 Output Host System Divided data N Sequence No.N These sentences are input into GNSS receiver without change. GNSS Receiver Sequence No.1 Divided data 1 Sequence No.2 Divided data 2 Input Backup Data (Backup RAM) Input Sequence No.3 Divided data 3 Host System Sequence No.N Divided data N Figure 7.6 Outline of Backup Data Input/Output 15

22 7.6.1 Backup Data Output Request Sequence To request a backup data output, input PERDAPI,STOP or PERDAPI,STOPNOFPR command to move the receiver state to the fix session off state. Input PERDSYS,BBRAM,QUERY command and output PERDSYS,BBRAM sentence in a row after the receiver state is in the fix session off state. When a command is input during the backup data is output, the receiver will process the command after completion of backup data output. Figure 7.7 shows the backup data output sequence. Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR :Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Host System $PERDSYS,FIXSESSION,OFF :Fix Session OFF $PERDSYS,BBRAM,QUERY :BBRAM Output Request Divided data are transferred. $PERDSYS,BBRAM : Backup Data Output Sequence No. 1/N $PERDSYS,BBRAM : Backup Data Output Sequence No. N/N $PERDSYS,BBRAM,CHKSUM : Backup Data Checksum Figure 7.7 Backup Data Output Session Sequence 16

23 7.6.2 Backup Data Input Sequence To request a backup data input, input PERDAPI,STOP or PERDAPI,STOPNOFPR command and input the data requested backup data output in numerical sequence after the receiver state is in the fix session off state. Figure 7.8 shows the backup data input sequence. Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR :Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Host System Divided data are transferred. $PERDSYS,FIXSESSION,OFF :Fix Session OFF $PERDSYS,BBRAM : Backup Data Input Sequence No. 1/N $PERDSYS,BBRAM : Backup Data Input Sequence No. N/N $PERDSYS,BBRAM,CHKSUM : Backup Data Checksum $PERDSYS,BBRAM,PASS Backup data input is comleted. 1) Figure 7.8 Backup Data Input Sequence Notes: 1) $PERDSYS,BBRAM,PASS*15 is output when the backup data can be input to the receiver. $PERDSYS,BBRAM,FAIL,MISSING, is output when the backup data cannot be input to the receiver. 1. Backup data is available in the receiver before input of backup data Once the receiver receives the backup data with sequence number 1, the existing backup data in the backup RAM will be invalid. 2. Receiver which is able to input backup data The backup data can be input to the same receiver which output the existing backup data. 3. Backup data invalid The receiver will not reflect the input of backup data in the following cases: a. Any commands except backup data are input during the input of backup data. b. A sequence number does not start from 1 or a sequence number is a lack of continuity. c. There is a check sum error in input data. d. There is a check sum error in backup data. 4. Recovery method when backup data cannot be input When the backup data cannot be input, input PERDCFG,FACTORYRESET 15 command and delete all backup data stored in the receiver, and then input again the backup data. 15 All backup data including ESIPLIST will be deleted by PERDCFG,FACTORYRESET command. When ESIPLIST is used, set ESIPLIST again. 17

24 7.7 Serial Communication Format Configuration Figure 7.9 shows the sequence when the receiver changes the serial communication format. The serial communication configuration should be changed in the fix session off state. The receiver outputs PERDACK sentence and reflects the configuration when PERDCFG,UART1 command is input in the fix session off state. Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR : Stop Request Host System $PERDACK,PERDAPI :Acknowledge (STOP) $PERDSYS,FIXSESSION,OFF :Fix session OFF $PERDCFG,UART1 : Serial Communication Setting $PERDACK,PERDCFG :Acknoledge (UART1) Reflected Setting Reflected Setting Figure 7.9 Session Sequence of Serial Communication Format Configuration 18

25 7.8 Time Setting This section shows the time setting sequence when the receiver s time is unknown. PERDAPI,TIME command is used to set the time. It is necessary to the following conditions to set the time: - RTC time is invalid. - The receiver does not get any time from GNSS satellites. Figure 7.10 and Figure 7.11 show the time setting sequences when the receiver conditions meet the above. In Figure 7.10, the time can be set by sending PERDAPI,TIME command during the time is unknown after sending PERDAPI,START command. Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR : Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Host System $PERDSYS,FIXSESSION,OFF $PERDAPI,START,COLD : Start Request (COLD or SIMCOLD) Time is uncertain. $PERDACK,PERDAPI : Acknowledge (START) $PERDSYS,FIXSESSION,ON $PERDAPI,TIME: Time Setting $PERDACK,PERDAPI : Acknowledge (TIME) Figure 7.10 Time Setting Sequence (Using START command) 19

26 Receiver Host System $PERDAPI,RESTART,COLD or $PERDAPI,RESTARTNOFPR,COLD : Restart Request (COLD or SIMCOLD) $PERDACK,PERDAPI :Acknowledge (RESTART) $PERDSYS,FIXSESSION,OFF $PERDSYS,FIXSESSION,ON Software Reset $GNRMC $GNGNS :PVT Data $GPGSV Time is uncertain. $PERDAPI,TIME: Time Setting $PERDACK,PERDAPI : Acknowledge (TIME) Figure 7.11 Time Setting Sequence (Using RESTART command) In Figure 7.11, the time can be set by sending PERDAPI,TIME command during the time is unknown after sending PERDAPI,RESTART command or PERDAPI,RESTARTNOFPR command and outputting PERDSYS,FIXSESSION,ON sentence and outputting PVT data ($GNRMC, $GNGNS, $GNGSV and etc.). 1. In case input of time setting command is delayed When the receiver time is fixed, the input time with PERDAPI,TIME command is not reflected because the receiver does not satisfy the condition that the receiver does not get any time from the satellites. 2. In case the wrong time (YYMMDD) is set When the difference between the actual date and the input date with PERDAPI,TIME command is less than +/-512 weeks, the receiver outputs a correct date once time data is obtained from the satellites. When the difference between the actual date and the input date with PERDAPI,TIME command is more than +/-512 weeks, the receiver will set a wrong rollover number of GPS week number starting from January 6 th, The receiver will calculate the date based on rollover number of GPS week number regardless of satellite used. When an error date which is more than +/-512 weeks is set, output date will have an error in increments of 1024 weeks. The wrong rollover number of GPS week number which set wrongly will not be corrected even if time data is obtained from the satellites. The rollover number of GPS week number will be corrected by resetting the date which is less than +/-512 weeks. 20

27 Figure 7.12 shows an example of setting of wrong rollover number of GPS week number. Current Date Error Date between Current Date and Input Date Input Date Time GPS Week Number s Rollover: 1 GPS Week Number s Rollover: 2 GPS Week Number s Rollover: 3 7 th April, st November, th July,2058 Figure 7.12 Relation between Current Date and Input Date The receiver sets 2 as a rollover number of GPS week number if the difference between the actual date and the input date is more than +/-512 weeks (Correct value is 1 ). Once time data is obtained from the satellites, the receiver will output the date based on the wrong rollover number of GPS week number:2 starting from 7 th April, 2019, GPS week number and GPS week time calculated by a time obtained from the satellites. (in this example, actual date plus 1024 weeks) 3. In case wrong time (HHMMSS) is set Even if a wrong time is input, the receiver will output a correct time once time data is obtained from the satellites. 21

28 7.9 Position Setting This section shows the position setting sequence when the receiver's position is unknown. PERDAPI,POS command is used to set the position. It is necessary that the position of receiver has not been fixed (no position fix) to input the position. Figure 7.13 and Figure 7.14 show position setting sequences when the conditions above are met. In Figure 7.13, the position can be set by PERDAPI,POS command during the position is not fixed after sending PERDAPI,START command. Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR : Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Host System $PERDSYS,FIXSESSION,OFF $PERDAPI,START,COLD : Start Request (COLD or SIMCOLD) Positon is uncertain. $PERDACK,PERDAPI : Acknowledge (START) $PERDSYS,FIXSESSION,ON $PERDAPI,POS: Positon Setting $PERDACK,PERDAPI : Acknowledge (POS) Figure 7.13 Position Setting Sequence (Using START command) 22

29 In Figure 7.14, the position can be set by sending PERDAPI,POS command during the position is not fixed after sending PERDAPI,RESTART command or PERDAPI,RESTARTNOFPR command and outputting PERDSYS,FIXSESSION,ON sentence and outputting PVT data ($GNRMC, $GNGNS, $GNGSV and etc.). Receiver Host System $PERDAPI,RESTART,COLD or $PERDAPI,RESTARTNOFPR : Restart Request (COLD or SIMCOLD) $PERDACK,PERDAPI :Acknowledge (RESTART) $PERDSYS,FIXSESSION,OFF $PERDSYS,FIXSESSION,ON Position is uncertain. Software Reset $GNRMC $GNGNS :PVT Data $GPGSV $PERDAPI,POS: Position Setting $PERDACK,PERDAPI : Acknowledge (POS) Figure 7.14 Position Setting Sequence (Using RESTART command) Here is the operation notice regarding position setting process from the host processor. 1. In case input of position setting command is delayed If the position has been fixed already, the condition no position fix is not met and the position set by PERDAPI,POS command will not be reflected. 2. In case wrong position is set The position error at the time of setting will be corrected once the positioning with satellite information is started. 23

30 7.10 ESIPLIST If it is necessary to automatically set up with command parameters, without having the host sending commands to the receiver, using the ESIPLIST function is ideal. This function programs the commands into the Flash ROM and sends the commands programmed at start-up automatically New ESIPLIST Create Figure 7.15 shows the ESIPLIST creating session sequence based on the below operation number from 1 to 5. New ESIPLIST Create Example Register the setting below in ESIPLIST newly. - Output CRE sentence - Set baud rate at bps Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR :Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) $PERDSYS,FIXSESION,OFF :Fix Session OFF Host System Operation 1. $PERDAPI,STOP*6F or $PERDAPI,STOPNOFPR*2A Send STOP command $PERDCFG,ESIPLIST,NEW*10 :Start ESIPLIST $PERDACK,PERDCFG :Acknowledge (ESIPLIST,NEW) $PERDAPI,CROUT,E*41 :Record command into ESIPLIST $PERDACK,PERDAPI :Acknowledge (CROUT) $PERDAPI,UART1,115200*65 :Record command into ESIPLIST $PERDACK,PERDAPI :Acknowledge (UART1) $PERDCFG,ESIPLIST,CLOSE*1A :Close ESIPLIST $PERDACK,PERDCFG :Acknowledge (ESIPLIST,CLOSE) 2. $PERDCFG,ESIPLIST,NEW*10 Start creating new ESIPLIST 3. $PERDAPI,CROUT,E*41 Register CRE sentence output 4. $PERDCFG,UART1,115200*65 Register Set baud rate to bps 5. $PERDCFG,ESIPLIST,CLOSE*1A Close creating ESIPLIST Figure 7.15 ESIPLIST Creating Session Sequence 24

31 ESIPLIST Append Figure 7.16 shows the session sequence of ESIPLIST appending with Tokyo datum as an example based on the below operation number from 1 to 4. ESIPLIST Append Example Add the setting below to the ESIPLIST created at Section Set Tokyo Datum Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR :Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Host System Operation 1. $PERDAPI,STOP*6F or $PERDAPI,STOPNOFPR*2A Send STOP command $PERDSYS,FIXSESION,OFF :Fix Session OFF $PERDCFG,ESIPLIST,APPEND*42 :Append ESIPLIST $PERDACK,PERDCFG :Acknowledge (ESIPLIST,Append) $PERDAPI,DATUM,172*26 :Record command into ESIPLIST $PERDACK,PERDAPI :Acknowledge (DATUM) $PERDCFG,ESIPLIST,CLOSE*1A :Close ESIPLIST $PERDACK,PERDCFG :Acknowledge (ESIPLIST,CLOSE) 2. $PERDCFG,ESIPLIST,APPEND*42 Start adding command to ESIPLIST 3. $PERDAPI,DATUM,172*26 Register Set Tokyo Datum 4. $PERDCFG,ESIPLIST,CLOSE*1A Close creating ESIPLIST Figure 7.16 ESIPLIST Appending Session Sequence 25

32 ESIPLIST Query The contents of ESIPLIST can be confirmed by sending "$PERDCFG,ESIPLIST,QUERY*06". The example below shows the procedures to confirm the contents of ESIPLIST set at Section and when the receiver is in the fix session off state. Receiver Host System Operation $PERDCFG,ESIPLIST,QUERY*06 :Query ESIPLIST $PERDCFG,ESIPLIST,BEGIN*0B Begin to output ESIPLIST $PERDAPI,CROUT,E*41 $PERDAPI,UART1,115200*65 $PERDAPI,DATUM,172*26 1. $PERDCFG,ESIPLIST,QUERY*06 Request output of ESIPLIST contents 2. Following data are output when the QUERY command is received. $PERDCFG,ESIPLIST,BEGIN*0B : Start outputting the contents $PERDAPI,CROUT,E*41 $PERDCFG,UART1,115200*65 : Registered commands $PERDAPI,DATUM,172*26 $PERDCFG,ESIPLIST,END*03 : Stop outputting the contents $PERDCFG,ESIPLIST,END*03 Finish to output ESIPLIST $PERDACK,PERDCFG :Acknowledgh (ESIPLIST,QUERY) 3. Acknowledgement (ACK) of Query ESIPLIST is output after outputting the contents of ESIPLIST. Figure 7.17 ESIPLIST Query Session Sequence ESIPLIST Delete Figure 7.18 shows the ESIPLIST delete session sequence based on the below operation number from 1 to 4. Receiver $PERDAPI,STOP or $PERDAPI,STOPNOFPR :Stop Request $PERDACK,PERDAPI :Acknowledgh (STOP) Host System Operation 1. $PERDAPI,STOP*6F or $PERDAPI,STOPNOFPR*2A Send STOP command $PERDSYS,FIXSESION,OFF $PERDCFG,ESIPLIST,DELETE*55 :Delete ESIPLIST $PERDACK,PERDCFG :Acknowledge (ESIPLIST,DELETE) 2. $PERDCFG,ESIPLIST,DELETE*55 Delete ESIPLIST $PERDCFG,ESIPLIST,QUERY*06 :Query ESIPLIST $PERDCFG,ESIPLIST,BEGIN*0B $PERDCFG,ESIPLIST,END*03 $PERDACK,PERDCFG :Acknowledge (ESIPLIST,QUERY) 3. $PERDCFG,ESIPLIST,QUERY*06 Check ESIPLIST data delete 4. $PERDCFG,ESIPLIST,BEGIN*0B $PERDCFG,ESIPLIST,END*03 Receive empty information of ESIPLIST Figure 7.18 ESIPLIST Delete Session Sequence 26

33 ESIPLIST Configurable Command Table 7.4 shows configurations of ESIPLIST for NMEA command. Table 7.4 NMEA Command Command name Description Registry configuration API CROUT Original sentence output DATUM Geodetic Datum DEFLS Default leap second EXTENDGSA GSA sentence re-definition FIRSTFIXFILTER First fix filter FIXMASK Satellite mask FIXPERSEC Multiple fixes per second GNSS GNSS configuration LATPROP Enable latency position propagation OUTPROP Enable position outage propagation PIN Pinning POS Position aiding N/A PPS Pulse per second RAIM RAIM RESTART/ RESTARTNOFPR Restart request N/A SBASBLS SBAS priority search select SELFEPH Self-Ephemeris TM mode ON/OFF START Start request N/A STATIC Statc entry/exit parameters STOP/STOPNOFPR Stop request N/A TIME Time aiding N/A CFG ESIPLIST Save/query ESIP commands to Flash ROM N/A FACTORYRESET Clear backup data in Backup RAM and Flash ROM N/A FORMAT Protocol format change NMEAOUT Configure the standard NMEA output SILENTSTART SILENTSTART mode UART1 Serial communication port configuration (UART1) UART2 Serial communication port configuration (UART2) SYS ANTSEL Antenna selection control BBRAM Backup data output query N/A ERRACT Receiver s state processing at exception operation FIXSESSION GNSS session query N/A GPIO GPIO output query N/A RECPLAY Diagnostic mode ON/OFF N/A SELFEPH Self-Ephemeris TM calculation time SELFTEST Self-test VERSION Software version query N/A : Registry is available to ESIPLIST N/A: Registry is prohibited or not applicable Here is operation notices regarding ESIPLIST registry process from the host processor. - Do not register the same command multiply with different setting. - In case duplicated commands are registered, the last command will be reflected. For example, in case register commands $PERDCFG,NMEAOUT,GGA,1*54 (output GGA sentence in 1 positioning cycle) followed by $PERDCFG,NMEAOUT,GGA,2*57 (output GGA sentence in 2 positioning cycles) in the ESIPLIST, the latter command $PERDCFG,NMEAOUT,GGA,2*57 is to be set. 27

34 ESIPLIST Executing Condition with EXECUTE command in ESIPLIST This section descries operation notices regarding an execution of ESIPLIST command by EXECUTE command which is PERDCFG,ESIPLIST,EXECUTE from the host processor. Table 7.5 shows valid conditions about each command class which is API, CFG and SYS class. API is the exclusive relation to CFG and SYS with START and EXECUTE command. Table 7.5 ESIPLIST Executing Condition Execute event of ESIPLIST API CFG SYS Transfer to the fix session on state by power on Transfer to the fix session on state by PERDAPI,START N/A N/A Send PERDCFG,ESIPLIST,EXECUTE N/A 1. In case that API class command is not included in ESIPLIST PERDCFG,ESIPLIST,EXECUTE command is available. 2. In case that only API class command is included in ESIPLIST Do not use EXECUTE command. If PERDCFG,ESIPLIST,EXECUTE command is sent, NACK may be returned. 3. In case that API and CFG,SYS class command are included in ESIPLIST ESIPLIST is executed by the procedure A, B or C. A) ESIPLIST is executed at the next power on after ESIPLIST is registered. B) Not using EXECUTE command (1) Create new ESIPLIST. (2) Send CFG and SYS class command which is registered in ESIPLIST. (3) Send START command. C) Use EXECUTE command (1) Register CFG and SYS class command in ESIPLIST. (2) Send EXECUTE command. (3) Append API class command to ESIPLIST. (4) Send START command. 28

35 7.11 Fix Session OFF Sequence Figure 7.19 shows the sequence transit from the fix session state to the fix session off state. Receiver Host System Fix Session $GNRMC $GNGNS $GNGST $GNGSA $GNZDA $GPGSV $PERDAPI,STOP or $PERDAPI,STOPNOFPR : Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Fix Session Off $PERDSYS,FIXSESSION,OFF :Fix Session Off Figure 7.19 Sequence Transit from Fix Session State to Fix Session OFF State 7.12 Power OFF Sequence Even if the receiver is turned off during positioning, the receiver will be operated properly at restart and the user can turn off the receiver at any timing. However, in case the receiver is turned off during writing the backup data in the BRAM area, the backup data can be invalid and not be used. There is no way to know when the backup data is saved in the BRAM area from the Host System. Therefore, by sending PERDAPI,STOP or PERDAPI,STOPNOFPR command to stop positioning before turning off the receiver at any timing, the possibility to destroy the backup data can be eliminated. The backup data will be written in the Flash ROM other than the BRAM when PERDAPI,STOP command is sent. After sending PERDAPI,STOP or PERDAPI,STOPNOFPR command, turn off the receiver after receiving PERDSYS,FIXSESSION,OFF sentence. Figure 7.20shows the power off sequence. Receiver Host System Fix Session $GNRMC $GNGNS $GNGST $GNGSA $GNZDA $GPGSV $PERDAPI,STOP or $PERDAPI,STOPNOFPR : Stop Request $PERDACK,PERDAPI :Acknowledge (STOP) Fix Session Off $PERDSYS,FIXSESSION,OFF :Fix Session Off 29 Power OFF Figure 7.20 Power OFF Sequence

36 7.13 Flash ROM Reprogramming See "Flash ROM Programming Procedures with WinUppg" (Doc # SE ) about Flash ROM reprogramming. 8 Receiving NMEA Sentence 8.1 Receiving Data Save all data received through UART1 of the receiver in the receive buffer of the Host System. 8.2 Cutout from String Start analyzing from the beginning buffer storing the received data with Section 8.1. Search for $ at first to cutout from the strings. If $ is found, search for * next. XOR in every 8 bit by using all the data between $ and * and compare with checksum in 1 byte (convert ASCII 2 character into 1 byte data in binary) followed by *. - If matches with checksum, determine as sentence satisfied and move to splitting the data. - If mismatched with checksum, determine as sentence not satisfied and discard the data. Discard <CR>,<LF> followed by checksum. If checksum is correct, read out 5 characters followed by $. The first 2 bytes represent Taker ID (GP, GL, GA, GN). Identify the sentence by the 3 characters followed by Talker ID. If the sentence is not supposed to be output (not set to be output), abnormal situation is suspected e.g. the command setting sentence output is not reflected properly or the receiver is restarted. 8.3 Cutout from Strings in Fixed Interval The receiver outputs positioning results with sentences set to be output once per positioning. For example, if the receiver is set to output RMC, GNS, GSV sentences once per positioning, these sentences are output once in a second in case of 1Hz positioning (GSV outputs multiple sentences depending on the number of satellites tracked or used satellite system). The order of sentences to be output is predetermined (see Section ). With this example, RMC comes out first followed by GNS, then GSV to be output at the last. Therefore, it can be regarded to have received a whole sentence for 1 positioning when RMC through GSV sentences are received. With 1Hz positioning, the interval to output sentence in each positioning is just about one second which may vary slightly depending on the time for position calculation. If the interval (the time between first RMC output and next RMC output) becomes more than two seconds, abnormal situation is suspected e.g. the baud rate is set improperly or the output from receiver has stopped. 8.4 Cutout from Every Strings The data fields in the string are split by,. Since the number of, is fixed depending on the sentence, abnormal sentence can be detected by checking the number of,. If abnormal sentence is detected, discard the sentence data. 30

37 8.5 TalkerID The Talker ID GP represents GPS, GL represents GLONASS, GA represents Galileo and GN represents multi-gnss (use multiple satellite systems). Except GSA and GSV sentence, only 1 sentence is read out in 1 output. The Talker ID can be discarded except GSA/GSV sentence especially in case separate the process in application by difference of positioning results between GPS, Galileo or multi-gnss. With GSA/GSV sentence, the GNSS system of Talker ID and that of data field in the sentence should be the same. With GSA sentence, the GNSS system can be identified by the satellite number and the GNSS system ID in the 18 th field. With GSV sentence, the GNSS system can be identified by the satellite number. If the GNSS systems are different in the same sentence, the data may be abnormal data. In this case, discard the data. 8.6 Satellite No. As described in Section 8.5, abnormal sentence can be detected by checking satellite number corresponding to each Talker ID because the GSA/GSV sentence output satellite number. GPS: 01 to 32 : Same as PRN No. SBAS: 33 to 51 : Subtract 87 from PRN No. QZSS: 93 to 97 : Subtract 100 from PRN No. Galileo: 01 to 36 : Same as PRN No. 8.7 Time in NMEA Sentence Time information is contained in data field of various sentences. The output sentences containing time information are as below: GBS, GGA, GLL, GNS, RMC, ZDA ZDA sentence represents current time (start time of sentence output of each position fix) and other sentences represent position fix time. For example, with the setting to output GNS and RMC sentence, the time of the same position fix in each sentence is correspondent. If not, abnormal situation is suspected e.g. abnormal sentence reception, missing data output from receiver or improper setting of baud rate. 31