Humminbird 737 - Manual (Page 14)

5
How GPS and Cartography Work
(with optional-purchase GPS Receiver)
With the purchase of an additional GPS Receiver, your 700 Series™ Fishing System also
supports GPS and chartplotting. With a GPS Receiver, your 737 uses GPS and sonar to
determine your position, display it on a grid, and provide detailed underwater information.
The Global Positioning System (GPS) is a satellite navigation system designed and
maintained by the U.S. Department of Defense. GPS was originally intended for military use;
however, civilians may also take advantage of its highly accurate position capabilities,
typically within +/- 10 meters, depending on conditions. This means that 95% of the time, the
GPS receiver will read a location within 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.
GPS uses a constellation of 24 satellites that continually send
radio signals to the earth. Your present position is determined
by receiving signals from up to 16 satellites and measuring
the distance from the satellites.
All satellites broadcast a uniquely coded signal once per
second at exactly the same time. 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.
The optional-purchase GPS Receiver, when used with your 700 Series™ Fishing System, allows
you to combine easy-to-use FishingGPS™ chartplotter and navigation capabilities with advanced
fishfinding. The following GPS functionality is currently supported by the 700 Series™ Fishing
System when it is connected to the optional-purchase 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.