Separation of multiple secondary surveillance radar sources in a real environment for the near-far case

Multilateration systems based on secondary surveillance radar (SSR) systems and omnidirectional antennae are operational today (Bezousek, 1998 and Galat, 2004). Assuming the replacement of the single-element antenna by an array, we proposed new algorithms to discriminate overlapped signals in previous works (Petrochilos et al., 2002, 2004 and 2007); other solutions were also proposed in the literature (Roy and Kailath, 1989; Chaumette et al., 1993; and van der Veen and Tol, 1997). Unfortunately, all have either some shortcomings, or an expensive computational cost, or no simple practical implementation. Therefore, we proposed in the work of Petrochilos et al. (2005) a reliable, simple, and effective projection algorithm. Nevertheless, some issues were overlooked: in particular the relative power ratio between the signals to be separated may be important, which we study in this paper with real-life signals.