SIM868_GNSS_AGPS_Application.pdf-资料库

SIM868_GNSS_AGPS_Application Note_V1.00 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision Document Title: SIM868_GNSS_AGPS_Application Note Version: Date: Status: 1.00 2017-01-03 Released Document Control ID: SIM868_GNSS_AGPS_Application Note_V1.00 General Notes SIMCom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by SIMCom. The information provided is based upon requirements specifically provided to SIMCom by the customers. SIMCom has not undertaken any independent search for additional relevant information, including any information that may be in the customer’s possession. Furthermore, system validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the customer or the customer’s system integrator. All specifications supplied herein are subject to change. Copyright This document contains proprietary technical information which is the property of SIMCom Limited., copying of this document and giving it to others and the using or communication of the contents thereof, are forbidden without express authority. Offenders are liable to the payment of damages. All rights reserved in the event of grant of a patent or the registration of a utility model or design. All specification supplied herein are subject to change without notice at any time. Copyright © Shanghai SIMCom Wireless Solutions Ltd. 2017 SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 3 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision Contents 1 Overview ....................................................................................................................................... 6 2 EPO orbit prediction .................................................................................................................... 7 EPO operation requirement ........................................................................................... 7 EPO orbit prediction process ......................................................................................... 7 EPO operation sample ................................................................................................... 7 2.1 2.2 2.3 3 SimFastFix function ................................................................................................................... 10 SimFastFix function requirement ................................................................................ 10 SimFastFix function process ....................................................................................... 10 SimFastFix function sample ........................................................................................ 10 3.1 3.2 3.3 Appendix ............................................................................................................................................ 13 A Related documents ..................................................................................................................... 13 B Terms and Abbreviations ........................................................................................................... 13 SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 4 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision Version history Date 2017-01-03 Version Description of change 1.00 New version Author Xiping.li Scope This document is a reference for SIM868 GSM+GPS+GLONASS module which is based on MTK platform. This document does not provide information about NMEA_0183 protocol. SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 5 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision 1 OVERVIEW SIM868 supports 3 kinds of fixing technologies, 1) GNSS EASY self-generated orbit prediction, off-line mode. 2) GNSS EPO orbit prediction, TTFF could be 10s minimum in open sky. 3) SimFastFix function, TTFF could be 5s minimum in open sky. Notice: 1) EASY technology is enabled in GNSS standard alone mode by default; first cold start will not help, after warm start, TTFF will be reduced to 15s around. EASY technology only takes 3 days ephemeris data from now on. 2) EPO and SimFastFix technologies require GPS UART interface to be connected to GSM UART2 interface as below. These two technologies will take effect immediately after cold start. GSM UART2_TX GPS_RXD GNSS UART2_RX GPS_TXD SIM868 SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 6 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision 2 EPO ORBIT PREDICTION 2.1 EPO operation requirement 1）UTC time is important before EPO data operation, because module will validate EPO data expiration date based on RTC time. You can get real time clock by following ways. a) Network time from cell tower by AT command AT+CLTS=1/AT&W. Next reboot module will get real time clock from network operator if it is supported, and update it to local RTC time which could be shown by command "AT+CCLK? ". b) Network time from NTP server. This will require GPRS service available. And enable SAPBR protocol for NTP function; please refer to document "SIM800 Series NTP Application Note.pdf". 2）EPO file from server. SIMCom provide FTP server for EPO file update regularly. Also, user can get MTK EPO file from different FTP or HTTP server. SIMCom FTP server provides EPO files for different days, and updates it every single day. FTP server address is: ftp://116.247.119.165, username is "customer" and password is "111111". 2.2 EPO orbit prediction process 1) Make sure module attach GPRS service; 2) Synchronize network UTC time; 3) Get EPO file from SIMCom ftp server and save it to module file system; 4) Enable GNSS and pass EPO file to GNSS engine; 5) Read GNSS fixing location from GNSS engine. Notice: EPO file should be re-installed after GNSS cold start. 2.3 EPO operation sample In the "Grammar" columns of following tables, input of AT commands are in black, module return values are in blue. Grammar AT+SAPBR=3,1,"CONTYPE","GPRS" OK AT+SAPBR=3,1,"APN","3GNET" OK AT+SAPBR=1,1 Description Set bearer parameter Set bearer context Active bearer context SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 7 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision OK AT+SAPBR=2,1 +SAPBR: 1,1,"10.73.119.61" OK AT+CNTPCID=1 OK AT+CNTP? +CNTP: 202.120.2.101.0 OK AT+CNTP OK +CNTP: 1 AT+CCLK? +CCLK: “16/12/15.11:02:32+0” OK AT+FTPSERV="116.247.119.165" OK AT+FTPUN="customer" OK AT+FTPPW="111111" OK AT+FTPGETNAME="MTK3.EPO" OK AT+FTPGETPATH="/" OK AT+FTPEXTGET=1 OK +FTPEXTGET: 1,0 AT+FTPEXTGET=4,"epo" +FTPEXTGET: 2,27648 OK AT+FSLS=C:\User\ Epo OK AT+CGNSCHK=3,1 +CGNSCHK: 3,1,27648,61 Read bearer parameter Set GPRS Bearer Profile’s ID Read NTP server and time zone parameter Synchronize Network Time to local Read local time Set FTP server address Set FTP user name Set FTP password Set download file name Set Download file path Download data to local buffer save data to local disk as EPO file List Directories/Files Check EPO file size and validation SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 8 SIMCOM CONFIDENTIAL FILE

Smart Machine Smart Decision OK AT+CGNSPWR=1 OK AT+CGNSAID=31,1,1 OK +CGNSAID: OK AT+CGNSINF +CGNSINF: 1,1,20161215045641.000,31.221303,121.355042 ,71.900,0.00,45.1,1,,1.0,1.3,0.8,,10,10,,,36,, OK Power on GPS Send EPO file to GPS EPO file has been written to GNSS buffer successfully Read GPS location data SIM928A868_GNSS_AGPS_Application Note_V 2017-01-03 9 SIMCOM CONFIDENTIAL FILE

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