The G-858 can be used with any GPS that can be configured to output serial data in the industry standard data format (NMEA 0183).  The G-858 console will log this data stream through a null model adapter.  After download, this data can be processed along with magnetic field measurements with our MagMap2000 software to provide a map or data file with the magnetometer's measurements positioned with the GPS values.

Two factors are important in the selection of the GPS receiver that will be used with the G-858: 1) the magnetic signature of the receiver and 2) the ability to configure the receiver to output only a particular NMEA 0183 sentence.  We recommend using GPS hardware components that generate less than 4 nT of signal at a distance of 30 cm from the G-858 sensor.  And the only data sentence that MagMap2000 needs is the $GPGGA sentence; there are many others and if they're transmitted, the G-858 will automatically record them, wasting console memory in the process. When configuring the GPS for the G-858 console set the GPS RS232 parameters to 9600 baud, 8 databits, No parity and 1 Stop bit.