SSR reply separation using array signal processing methods

The SSR mode S data link capability can be improved using ground stations with non-rotating wide-beam antennas. The main problem with wide beam antennas is the corruption of replies by fruit replies. Therefore a method to separate overlapping replies is required. A new approach to the separation of SSR replies is the application of array processing methods that use the signal structure of the reply and the spatial difference between the incoming signals. Methods have been developed to successfully separate continuous digital signals like FM and BSPK, however SSR signals have different properties. Three signal separation methods from the field of communications have been selected, which have the opportunity to apply them to the problem of overlapping SSR reply signals