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

    • C/A-Code

    • P-Code

    • Carrier

  • L2-Frequency (1227,60 MHz) = 24,45 cm wavelenght

    • P-Code

    • Carrier

Author: Michael Schulz, GEOSOFT