Global Positioning System. = (GPS) A system for determining position on the Earth's surface by comparing radio signals from several satellites. When completed the system will consist of 24 satellites equipped with radio transmitters and atomic Clocks.
Depending on your geographic location, the GPS receiver samples data from up to six satellites, it then calculates the time taken for each satellite signal to reach the GPS receiver, and from the difference in time of reception, determines your location.
You can break the process down in to 5 easy steps
1. Triangulation form satellites is the basis
of the system
2. To triangulate, GPS measures distance
using the travel time of a radio message
3. To measure travel time, GPS needs very
accurate clock
4. Once you know distance to a satellite,
you then need to know where the satellite is in space
5. As the GPS signal travels though the ionosphere
and the earth’s atmosphere it gets delayed
The information that you receive is raw data.
That needs to be corrected due to the movement of the rover unit and other
sources of error. There are base stations that don’t move and collect
constant data with accuracy down to millimeters. The closest one,
the one that we use it in by Alma near the Mississippi River. (STP1)
here data is constantly corrected because it doesn’t move and has data
correcting equipment.