Çoğul FM radyo kanalı kullanılarak pasif tutarlı konumlama radar sistemlerinde uzaklık çözünürlüğü artırma

Passive coherent location (PCL) radar systems that use single FM radio channelsignal as illuminator of opportunity have reasonable Doppler resolution, butsuffer from limited range resolution due to low modulation bandwidth and highdependence on the content that is being broadcasted from the FM station. Animprovement in range resolution is obtained by using multiple adjacent FMchannels, emitted from co-sited transmitters, which is often the case in largetowns. The proposed scheme computes the autocorrelation function of the signaldirectly received from the co-located FM transmitter, and compares it to thecross-ambiguity function, obtained from direct and target scattered signals. Thegeometry of the problem is like in the case of monostatic radar. The rangeinformation is obtained by the delay between the cross-ambiguity function andthe autocorrelation function. When a single FM channel that has a modulationbandwidth of 25 kHz is employed the range resolution is 6 km. It is shown thatdown to −33dB signal to noise ratio (SNR), which corresponds to a distance of110 km from the receiver, targets that are 3 km separated from each other canbe detected with 3 adjacent FM channels. It is possible to detect targets that are100 m separated from each other with 7 FM channels. The detection of the timedelays is a linear estimation problem.Keywords: Passive coherent location (PCL), range resolution, modulationbandwidth, FM radio, cross-ambiguity.