Humminbird 900 Series - Manual (Page 11)

Universal Sonar 2
Your 900 Series™ Fishing System supports Universal Sonar 2, a state-of-the-
art, integrated and protected transducer that is built into the lower unit of
Minnkota trolling motors. With Universal Sonar 2, all wiring is concealed
inside the indestructible composite shaft—out of sight and out of harm’s
way, with no clamps, ties, or exposed wires. Universal Sonar 2 features new
temperature sensing and the performance of DualBeam PLUS™ technology.
An expanded view and greater bottom detail gives you a totally new
perspective of the water below, along with optimal sonar performance to
help you find fish.
How GPS and Cartography Work
Your 900 Series™ Fishing System also supports GPS and chartplotting, and
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 GPS Receiver included with your 900 Series™ Fishing System allows you
to combine easy-to-use FishingGPS® chartplotter and navigation capabilities
with advanced fishfinding.
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