Humminbird 998c SI - Manual (Page 14)

Introduction 4
Universal Sonar 2
Your 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 Fishing System 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 Fishing System
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 Multi-Media Card (MMC)/SD Slots:
Add Maps to Your Fishing System for more information.