What characterizes ground VOR checkpoints?

Ground VOR checkpoints are specifically designated reference points located in the vicinity of an airport. These checkpoints serve a crucial role in ensuring that pilots can verify their navigational equipment's accuracy and functionality, providing a reliable means of assessing their instrument approach capabilities. By situating these checkpoints around airports, air traffic controllers and flight instructors can facilitate effective training and navigation practices for pilots, particularly those engaging in instrument flight rules (IFR) operations.

These points are strategically placed to assist pilots in safely transitioning from en route navigation to terminal operations, ensuring they have a clear understanding of their position in relation to the airport environment. This focus on specific airport-adjacent locations is fundamental to the instructional techniques taught during instrument training and enhances the overall safety of IFR flying.

The other options do not accurately capture the nature of ground VOR checkpoints, as they are not random locations, nor are they exclusive to airspace boundaries or limited to controlled airspace. Instead, they are purposefully established near airports to aid in the training and navigational accuracy of pilots.