What is the purpose of the Global Positioning System (GPS)?

• A. A weather data receiver
• B. A ground-based navigation system using radio beacons
• C. An inertial measurement unit only
• D. A navigation that receives reference information from a satellite source; Provides the pilot and other aircraft systems continuously updated present position, velocity and time information.

Answer: (D)

Global Positioning System is a satellite-based navigation system that provides continuous updates of position, velocity, and time by receiving signals from a constellation of orbiting satellites. A GPS receiver determines where you are, how fast you’re moving, and the exact time by measuring how long signals from multiple satellites take to reach you, then solving for your coordinates and clock error. This satellite reference data feeds the aircraft’s navigation and timing systems, enabling accurate position and velocity information to be used across pilot displays and onboard systems. It isn’t a weather data receiver, not a ground-based beacon system, and it isn’t just an inertial measurement unit—IMUs measure motion internally, while GPS provides external reference data to continuously define where you are and what time it is.