User Manual

2
How GPS and Trackplotting Work
Your Humminbird® uses GPS to determine your
position and display it on a grid.
GPS uses a constellation of satellites that
continually send radio signals to the earth. The
GPS receiver on your boat receives signals from
satellites that are visible to it. Based on time
differences between each received signal, the
GPS receiver determines its distance to each
satellite. With distances known, the GPS receiver
mathematically triangulates its own position.
With 5 updates per second, the GPS receiver then
calculates its velocity and bearing.
GPS was originally intended for military use; however, civilians may also take
advantage of its highly accurate position capabilities, typically within +/– 2.5
to 10 meters, depending on your conditions and your Humminbird® model. This
means that 95% of the time, the GPS receiver will read a location within
+/– 2.5 to 10 meters of your actual position.
Your GPS receiver also uses information from WAAS (the Wide Area
Augmentation System), EGNOS (the European Geostationary Navigation
Overlay Service), and MSAS (the MTSAT Satellite Augmentation System)
satellites if they are available in your area.
Overview