Editing Tactical air navigation system (section)

==Drawbacks==
For military usage a primary drawback is lack of the ability to control emissions ([[EMCON]]) and stealth. Naval TACAN operations are designed so an aircraft can find the ship and land. Since there is no encryption, an enemy can use the range and bearing provided to attack a ship equipped with a TACAN. Some TACANs have the ability to employ a "Demand Only" mode: only transmitting when interrogated by an aircraft on-channel. It is likely that TACAN will be replaced with a differential GPS system similar to the [[Local Area Augmentation System]] called JPALS. The [[Joint Precision Approach and Landing System]] has a low probability of intercept to prevent enemy detection and an aircraft carrier version can be used for [[autoland]] operations.

Some systems used in the United States modulate the transmitted signal by using a 900 RPM rotating antenna. This antenna is fairly large and must rotate 24 hours a day, possibly causing reliability issues. Modern systems have antennas that use electronic rotation (instead of mechanical rotation), hence no moving parts.