| There are 24 active Navstar satellites orbiting the earth at about 12,000 nautical miles above the earth. They are continuously sending signals on L1 channel on 1575.42 MHz for civilian uses. The signals contain the synchronization code, identification code, position and time codes. With the installed aircraft systems, the distant of the aircraft to the satellite is calculated. With four satellites signal received and analysed, the aircraft will be able to locate its position. Other parameters are derived from the instantaneous position of the aircraft. |
