The GS820 TMC uses a sensor coil that can “read” the compass it is attached to.

The resulting signal is in industry-standard NMEA for sharing with other equipment such as autopilots and VDRs. It can also be used as an input for heading repeaters such as the P1920 Steering repeater or P1251 UDDU multifunction display.

The P1913 sensor coil used in the GS820 has been designed with high tolerances for magnetic strength so it can be used with a wide variety of compasses. It is also remarkably easy to fit. With options for additional brackets if needed for other compasses or a neat removable solution for top mounting.

The main electronics unit in the GS820 also acts as an indicator with options to show either the compass heading (as shown on the compass) or the magnetic heading (corrected for the ship’s deviation) in either numerical or tape form.