Clutter mitigation in sub-Nyquist radars using difference set codes

In this study, the authors address the issue of clutter mitigation in monostatic pulse-Doppler radars, using sub-Nyquist sampling and compressed sensing (CS) recovery algorithms. Generally, clutter is modelled as a coloured random process and a whitening filter is employed to maximise the signal to clutter ratio. Here, the authors apply this approach to the case in which the received signal sampling rate is much smaller than the Nyquist rate. They also generalise the recently proposed sub-Nyquist method based on difference set (DS) codes, which uses very few samples to detect targets in the presence of only white Gaussian noise. By using the frequency-coded modulation waveform with the frequencies selected in accordance to the DS, the detection performance of the proposed method can be significantly improved compared with the previously proposed sub-Nyquist methods in the presence of clutter. Furthermore, the authors show that the proposed method can increase the target recovery resolution due to the features of the DS codes and the employed CS model.