GM862-GPS Software User Guide - SemiconductorStore.com

GM862-GPS Software User Guide1vv0300729 Rev. 4 - 24/01/075 GPS operations5.1 IntroductionThe GM862-GPS module is equipped with a SiRFStar III GPS receiver that is controllable by the GSMmodem using a setof AT commands or dedicated NMEA sentences.5.2 GM862-GPS Serial Ports2 serial ports are available on the module:• MODEM SERIAL PORT• GPS SERIAL PORT B (NMEA)5.2.1 GPS SERIAL PORT B (NMEA)This port is carrying out the GPS navigation data in NMEA 0183 format.The default configuration is 4800 bps, 8, n, 1It is available on the following pins:PIN # NAME DESCRIPTION TYPE35 TX_GPS GPS TX Data (NMEA) CMOS 2.8V41 RX_GPS GPS RX Data (NMEA) CMOS 2.8V5.3 WGS 84GPS receivers perform initial position and velocity calculations using an earth-centered earth-fixed(ECEF) coordinate system. Results may be converted to an earth model (geoid) defined by theselected datum. For GM862-GPS the default datum is WGS 84 (World Geodetic System 1984) whichprovides a worldwide common grid system that may be translated into local coordinate systems ormap datums. (Local map datums are a best fit to the local shape of the earth and not valid worldwide).Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 95 of 111