Which navigation system uses satellite data to provide continuously updated present position, velocity, and time information?

• A. Intercommunication Audio System (IAS)
• B. Inertial Navigation System (INS)
• C. Tactical Air Navigation (TACAN)
• D. Global Positioning System (GPS)

Answer: (D)

Global Positioning System is the system that uses signals from satellites to provide continuously updated present position, velocity, and time information. A receiver picks up signals from multiple satellites, measures how long each signal took to arrive, and uses those measurements to solve for your exact 3D position and precise receiver time. Velocity comes from Doppler shifts of the satellite signals and the changing position over time, giving you a continuous update of how fast and in what direction you’re moving. This satellite-based approach provides global, real-time PVT data, unlike systems that rely on onboard sensors (inertial navigation) or ground-based aids (TACAN), which don’t offer the same continuous worldwide satellite coverage.