Networking & Connectivity Heading Sensor

A heading sensor is an electronic compass that provides your boat's magnetic heading to the fish finder and chartplotter via NMEA 2000 or NMEA 0183. While GPS can determine your direction of travel when moving, it cannot detect which way the boat is pointing when stationary or moving very slowly. A heading sensor fills this gap by continuously reporting magnetic heading regardless of boat speed or movement.

Accurate heading data improves several fish finder functions. Chart rotation — orienting the map so that the direction you are pointing is always at the top of the screen — becomes smooth and responsive with a heading sensor. Without one, the chart only updates its orientation when you move fast enough for GPS to determine course over ground, causing the map to spin erratically at low speeds or when drifting.

Heading sensors also stabilize side imaging and live sonar displays by compensating for the boat's yaw, pitch, and roll. Without heading correction, wave action and wind push can distort imaging data, making structure appear shifted or stretched. A quality heading sensor helps the sonar processor account for boat motion and keep the displayed image accurate.

External heading sensors come as standalone pucks or integrated into GPS antenna units. The Garmin GPS 24xd, for example, combines a GPS receiver with a heading sensor in one unit. Heading sensors should be mounted away from large metal objects, speakers, and trolling motors that can interfere with the magnetic compass accuracy.