What does the air data computer provide when used with GNSS?

The air data computer, when integrated with a Global Navigation Satellite System (GNSS), provides true airspeed. This is because the system takes into account the actual atmospheric conditions, including temperature and pressure, allowing for the calculation of true airspeed rather than merely relying on pressures or readings that might be influenced by drag or other aerodynamic factors at a given altitude.

True airspeed is the speed of an aircraft relative to the air mass surrounding it and is vital for precise navigation, flight planning, and performance calculations. The GNSS complements the air data computer by providing information about the aircraft's position and movement over the ground, leading to an accurate representation of the aircraft's true performance in the atmosphere.

Other options, such as indicated airspeed and calibrated airspeed, are derived from pilot instruments and do not account for altitude and temperature variations effectively, while ground speed represents the speed of the aircraft relative to the ground, which is influenced by wind conditions. Thus, the combination of the air data computer and GNSS specifically delivers the measurement needed for true airspeed.