Airport Surveillance Radar abbreviated as ASR is a radar system that are place in airports for detecting the position of aircraft and used by Air Traffic Controllers (ATC) for air traffic flow management to monitor flights, ensure safety, efficiency and enhanced situational awareness. ASR systems usually contain a primary and secondary radar. The primary radar consists of a continually rotating antenna transmitting electromagnetic radiation that backscatters as an echo from the surface of an aircraft. By measuring the time delay of the echo, the aircraft is detected at long ranges. The secondary radar uses a radar beacon antenna to transmit and receive aircraft data such as identification codes, barometric altitude etc. Transmitting power ranges for the primary radar can be upto 25 kW whereas the secondary radar from 100 W to 2000 W.
