Task: Text Simplification
Input (English): Very High Frequency ( VHF ) Omni-Directional Range ( VOR ) is a type of short-range radio navigation system for aircraft , enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons .
Output (English): VOR , short for VHF omnidirectional radio range , is a type of radio navigation system for aircraft , enabling them to find their position and stay on course by receiving radio signals emitted by a network of radio beacons .