October 3, 2011 § Leave a comment
A Global Navigation Satellite System (GNSS), is a global system of satellites that provide geo-spatial positioning.
All satellites are synchronized via atomic clock. Times are compared with time-to flight. Measurements are made at the same time to different satellites, generate a continual fix in real time using an adapted version of trilateration (the process of determining absolute or relative locations of points by measurement of distances, using the geometry of circles, spheres, or triangles).
The United State’s NAVSTAR Global Positioning System (GPS), is the only fully operational GNSS as of 2010.
(Trimble has explains GPS here.)