Blind separation of secondary radar signals using time-frequency analysis

In Secondary Surveillance Radar (SSR) systems, it is more difficult to locate and recognise aircrafts in the neighbourhood of civil airports since aerial traffic becomes greater. Here, we propose to apply a recent Blind Source Separation (BSS) algorithm based on Time-Frequency Analysis, in order to separate messages sent by different aircrafts and falling in the same radar beam in reception. The above source separation method involves joint-diagonalization of a set of smoothed version of spatial Wigner-Ville distributions. The technique makes use of the difference in the t - f signatures of the nonstationary sources to be separated. Consequently, as the SSR sources emit different messages at different frequencies, the above method is fitted to this new application. We applied the technique in simulation to separate SSR replies. Results are provided at the end of the paper.