Humminbird 1155C - Manual (Page 9)

1100 Series™ Introduction
Your 1100 Series™ Chartplotter comes in the following configuration:
• Humminbird® 1155c Chartplotter: Networkable GPS Chartplotting System, GPS Receiver
included.
How GPS and Cartography Work
Your 1100 Series™ Chartplotter supports GPS and chartplotting, and uses GPS to determine your position
and display it on a grid. 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.
1