CHIMBORAZO AS - Mats Kågstrøm  
Offshore Survey, Positioning & Software Consultant


AIS SimulatorAIS Analyser

NMEA SUITENMEA SimulatorNMEA AnalyserNMEA ComposerNMEA MonitorNMEA BroadcastNMEA WinsockNMEA GPS compass

Geodetic CalculatorsGeoMathUS State Plane

Loran C
Loran Estimator

Line Of Sight




  NMEA GPS Compass

 If you have 2 GPS receivers with the antennae installed with most possible separation in meters, this program will calculate an estimate of the ships true heading. The calculation is simply done as an azimuth from aft antenna position to forward antenna position. After adjusting for antenna offsets this is transferred to the ships heading.

 It must be noted that this is a not a proper GPS compass utilizing carrier phase measurement and as such the accuracy will be very limited. The intention will never be to replace a gyro compass. The accuracy will also be strictly dependent on the separation between the antennae. A separation of only a few meters has no meaning.

 The antennae can be installed anywhere on the ship, but the offset has to be precise measured and entered in setup.

     Input : 2 x NMEA GGA msg from 2 GPS with best possible separation in meters between antennae

     Optionally output : NMEA HDT message


 For pricing information, please contact Mats Kågstrøm : 

 Updated : 27.01.2013