Samyung NAVIS800FS, Instruction Manual

Page: 4 / 104

4
1. GPS Overview
The Global Positioning System is based on a radio navigational system using satellites. An unlimited number
of users are provided with accurate three-dimensional positions. This 24/7, worldwide coverage, is available
under any weather condition.
GPS can provide two-dimensional and three-dimensional position information. 3D positioning is mostly used
in aircraft or other applications requiring
latitude, longitude and altitude . The 3D mode requires a lock on 4
satellites to accurately acquire the position.
Surface vessels use 2D positioning, as only latitude and longitude is needed. In 2D mode, positioning
requires a lock on only 3 satellites to accurately acquire the position.
Once the GPS Plotter has received an accurate fix from the satellites, ship
’s position, bearing, time, speed
and other operations can be calculated.
GPS(Global Positioning System) has two types, 3 Dimensional and 2 Dimensional.
3D positional data has been sued in aviation, which requires Latitude, Longitude and Height.
To provide 3D positional data, the system requires 4 satellites.
2D positional data has been used in vessel/ship navigation, which requires only Latitude and Longitude.
To provide 2D positional data, the system requires 3 satellites.
GPS provides an accurate positional data by receiving satellite signals.
GPS chartplotters provide ship position, bearing, time, speed and many more.
Furthermore, plotters provide information for navigation and other data on the map
such as latitude/longitude, tracks, waypoints, event marks and more on high-resolution LCD.