How does GPS work?
The GPS satellites send out unique and predictable signals.
Figure 2.1: Satellite Signal
The Master Control Station in Colorado Springs updates the GPS satellites with predicted positions (ephemeries) and controls the GPS time.
The GPS observables are two carriers containing code:
L1-Frequency (1575,42 MHz) = 19,05 cm wavelenght
L2-Frequency (1227,60 MHz) = 24,45 cm wavelenght
Author: Michael Schulz, GEOSOFT