Which system is used to determine bearing and slant range to a TACAN ground station?

• A. GPS
• B. TACAN
• C. INS
• D. ILS

Answer: (B)

TACAN is the system that provides both azimuth bearing and distance to a TACAN ground station. The bearing comes from the azimuth signal of the TACAN station, which your receiver decodes to show the angle to the station. The distance, or slant range, is obtained from the DME function, which measures the round-trip travel time of a radio pulse between aircraft and ground station and converts that into a distance. In combination, you know exactly where the TACAN station is relative to you.

GPS, INS, and ILS don’t furnish this pair of data to locate a TACAN station. GPS gives global position from satellites, INS estimates position from inertial sensors, and ILS is an approach aid for runway alignment, not bearing and range to TACAN.