Nowadays, the radar systems are much more important for the air traffic control, so in this paper, the primary and secondary air traffic control radars from its theory and mathematics to the application in real environment have been introduced. The primary and secondary radar systems must be applied parallel for the cooperative and non-cooperative target detection.
For the secondary radar reply signal detection and its digital base-band signal processing, a secondary radar reply signal receiver is developed, and the digital signal processing part is programmed in Matlab and LabView environments. These programs are tested with simulated and real received radar reply signals, and are in right order.
These programs are a part of the radar system, which is developed at the laboratory based on multilateration (multistatic passive radar system).