How Gps And Cartography Work - Humminbird HELIX 5 SERIES Operation Manual

How GPS and Cartography Work

Your control head 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 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 (thes 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 control head:
• 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 Views: Chart View and microSD Card Slot: Add Maps to your Control Head for more
information.
How GPS and Cartography Work
GPS uses a constellation of satellites that continually send radio
signals to the earth. The GPS receiver receives signals from satellites
that are visible to it. Based on time differences between each
received signal, the GPS receiver determines its distance to seach
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.
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