What does VOR stand for in aviation navigation?

In aviation navigation, VOR stands for VHF Omnidirectional Range. This system is crucial for pilots as it provides reliable and accurate readings of an aircraft's position relative to the VOR station. The VOR stations emit very high frequency (VHF) radio signals that create a reception area allowing aircraft to determine their bearing from the station on a 360-degree magnetic compass. By using this information, pilots can navigate by following specific radial courses to or from the VOR station, making it an essential component of modern aviation navigation.

The other options presented do not pertain to aviation navigation. Variable Optical Radiation, Vertical Operational Range, and Vortex Oscillation Rate are not recognized standards or systems used in the context of navigation within aviation. The VOR system is widely used for its effectiveness in providing pilots with a reliable means of navigating, especially in areas where visual navigation is not possible.