Signal Conditioning for DAB-Illuminated Passive Radar

In this paper, we present the signal processing algorithm for improving DAB signals received in the Passive Coherent Location (PCL) system. Due to the synchronous time-domain structure of the DAB signal, there are artifacts visible in bistatic velocity/range images that repeat regularly and distort the detection results. We investigate the structure of the DAB signal and its impact on the signal's autocorrelation function. There are periodic peaks in the autocorrelation function that result from the repetition of deterministic portions in DAB frames. Such properties of the signal are not desirable in PCL because of detection performance degradation. We propose the algorithm to suppress the unwanted autocorrelation peaks by removing a few symbols from the DAB frame. The experimental results with real DAB signal show that it is possible to eliminate these peaks by proper selection of the symbols to remove.