Passive surveillance system for air traffic control

A new passive radar based on the multilateration Time Difference Of Arrival (TDOA) technique is presented. The radar is dedicated for Air Traffic Control purposes. The system utilises Secondary Surveillance Radar (SSR) aircraft transponder´s reply signals to locate, identify and track aircraft in the large area. The radar system consists of three Receiving Stations, Signal Processor and Situation Display. The Receiving Stations are placed in terrain on three properly selected posts. All signals received by Receiving Stations are led to the Signal Processor. It finds corresponding reply code groups from three input signal/data flows and evaluates their Time Difference Of Arrival. On the basis of these time differences the location of aircraft is computed. A demonstrator of such passive system was produced. A structure, technical parameters and microwave and signal processing technologies applied in the system are illustrated in this paper. Also practical results from 1 year exploitation and tests of the system are briefly presented.