Adaptive equalizer for Mode S receiver

Mode S or mode “select” is a sort for a data exchange protocol used for air surveillance purposes. In here “select” means that the radar addresses its interrogation to one particular aircraft instead of interrogation with all planes inside the main beam of the radar antenna. Because of high equipage of Mode S transponders, it has become one of the cornerstones of today´s air surveillance used for air traffic control purposes. Because of complex environments, such as airports with high number of reflecting surfaces and Mode S capable transponders, state-of-the-art algorithms must be used to overcome problems and to achieve maximum benefit from using enhanced surveillance systems. In this paper we investigate channel equalizer for Mode S receiver based on a combination of two adaptive filters.