Plain English Meaning

A small radio station on the ground that sends out one steady test signal so a pilot can check whether their VOR navigation equipment is reading correctly before flight.

Full Definition

A ground-based radio facility that transmits a single, fixed test signal used by pilots to verify the accuracy of their aircraft's VOR receiver. The VOT broadcasts an omnidirectional signal that simulates a radial from magnetic north, so a correctly functioning VOR receiver tuned to the VOT frequency will display 0° FROM (or 180° TO) regardless of the aircraft's actual . error during the check is ±4°.