The required 24 NAVSTAR/GPS operational satellites are located on:
Domanda 209, Radio Navigation - ATPL - Airline Transport Pilot license
| 4 orbital planes with 6 satellites in each plane |
| 3 orbital planes with 8 satellites in each plane |
| 6 orbital planes with 3 satellites in each plane plus 6 reserve satellites positioned in a geostationary orbital plane |
| Timing the period that is taken for a transmission from the aircraft's transmitter/receiver to reach and return from a satellite in a known position |
