In which frequency band do satellite assisted navigation systems (GNSS/GPS) provide position information that is available to civil aircraft?

Satellite assisted navigation systems, such as GNSS (Global Navigation Satellite System) and GPS (Global Positioning System), operate primarily in the UHF (Ultra High Frequency) band. This band is crucial for the transmission of position, navigation, and timing information to users on the ground and in the air, including civil aircraft.

The UHF frequency range allows signals to be transmitted over long distances with relatively low power, which is particularly beneficial for satellite communications. The signals used in GNSS typically operate at frequencies around 1.57542 GHz for L1 (the most commonly used frequency in civilian applications) and other frequencies for different services, all of which fall within the UHF band.

In contrast, other frequency bands such as EHF (Extremely High Frequency), SHF (Super High Frequency), and VHF (Very High Frequency) are not used for standard GNSS/GPS signals aimed at providing positional information to civil aircraft. EHF frequencies are primarily used for specialized military communications, SHF is often used for radar and high-capacity communications, and VHF primarily serves terrestrial communication and aviation voice communications rather than satellite navigation. Thus, the UHF band is the correct choice for satellite-supplied navigation data in aviation.