Accurate compass heading data remains a fundamental parameter for marine navigation and the HSC100 uses fluxgate technology to deliver heading data for on board systems. Typical applications include enabling course up and true motion-type displays on chart plotters, radar overlay onto electronic charts and stabilization of radars when used for MARPA/ARPA target tracking. Integrated instrument systems can also benefit from having compass information to calculate real time tidal set and drift when interfaced with a log and GPS. Most low cost heading sensors only output data at 1 Hz (once per second) but the HSC100 outputs at 10 Hz which is required for MARPA target tracking and accurate radar overlays (Part No. ZDIGHSC100). We have also released a new rate of turn version of the HSC100 that outputs the HDT and ROT messages required by a Class A transponder. For non-mandatory vessels, this provides a simple low cost solution for adding heading and rate of turn to Class A transponders.