Operators use it to provide reference points to aid in controlling aircraft. IFF interrogates aircraft and ships with an electronic code. If the aircraft is equipped with the proper equipment, it responds with a coded reply. The reply is then displayed on the radar indicator. The radar video and the IFF replay must be properly placed to ensure accuracy.
Civilian authorities use it as an aid in tracking aircraft.
In addition to air traffic control, virtually all military forces use IFF for its original purpose - to identify possible hostile aircraft and ships. Many newer radar systems are either computer controlled or based on computer technology. The trigger function will also develop this waveform. MTI functions use digital circuits for short-term , volatile data storage, video processing, and delay lines. A digital delay line is cheaper, smaller, and easier to maintain than the analog devices it replaced.