Humminbird 300 SERIES 365I - Manual (Page 15)

5
How GPS Works
Your 300 Series™ Fishfinder also supports GPS (Global Positioning System) and
chartplotting. It uses GPS and sonar to determine your position, display it on a
grid, and provide detailed underwater information.
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
once per second updates, 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 +/- 4.5
meters, depending on conditions. This means that 95% of the time, the GPS
receiver will read a location within 4.5 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.
The following GPS functionality is currently supported by the 300 Series™
Fishfinder when it is connected to the included GPS receiver:
• View current position
• View current track (breadcrumb trail)
• View precision speed and heading from your GPS receiver
• Save tracks, waypoints, and routes
• Travel a route and navigate from one waypoint to the next.
See Chart View and Introduction to Navigation: Add Maps to Your Fishfinder
for more information.
How GPS Works