What is the basic function of the aircraft TACAN subsystem?

The basic function of the aircraft TACAN (Tactical Air Navigation) subsystem is to provide navigation information. TACAN is a radio navigation system that allows aircraft to determine their position relative to a TACAN ground station. It operates by sending signals from the aircraft to the ground station and receiving responses, which helps in calculating distance and bearing. This information is critical for pilots to navigate accurately, especially in environments where visual navigation may be limited.

The other options—transmitting images, recording flight data, and enhancing communication—while essential functions in aviation, do not relate specifically to the primary role of the TACAN subsystem. TACAN focuses solely on navigation assistance, making it an invaluable tool for both military and civilian pilots as they navigate through airspace.