Which of the following is not classified as a satellite-based navigation system?

The VOR (VHF Omnidirectional Range) system is not classified as a satellite-based navigation system because it relies on ground-based radio signals rather than satellite signals. VOR operates by transmitting radio frequency signals from a network of fixed ground stations, allowing aircraft to determine their position relative to these stations. This terrestrial method of navigation contrasts with systems such as GPS, GLONASS, and Galileo, which utilize a constellation of satellites to provide positioning information. The features of satellite-based systems enable worldwide coverage and greater accuracy compared to ground-based systems, highlighting the difference between VOR and those classified as satellite-based.