Bistatic radars: clutter modeling and target detection

In the first part of this work we analyse the sea clutter data collected simultaneously by the bistatic and monostatic nodes of the NetRAD, which is a netted radar system working at S band, whereas the datasets have been collected with four different out-of-plane geometries. Particular attention is paid to characterize the variation of the main statistical and spectral features of the bistatic sea-clutter according to the polarization and the bistatic geometry. The aim of the analyses consists in examining the spikiness of bistatic clutter, compared with the monostatic one, which will be useful for the design of the radar detectors. In the Doppler domain, sea spikes are mainly concentrated within the peak of the clutter spectrum and their presence makes the spectrum wider. These features are examined in this work by a comparison among the Doppler spectra of the total received samples, of the background and of the spikes. From a statistical point of view, the presence of sea spikes is examined by comparing the data histograms with some heavy-tailed distributions and by studying the behaviour of two explicative statistical parameters, such as kurtosis and shape parameter. The statistical distributions of the spike width and of the interval between two subsequent spikes are also analysed. The second part of this work addresses the problem of target detection for bistatic and, in a more general way, multistatic and multiple input - multiple output radars. The adopted algorithm is able to keep constant the false alarm rate, if the disturbance samples associated to each receiver-transmitter pair are distributed according to a Compound-Gaussian model. In particular, the performance of the adopted detection algorithm is analyzed, in order to evaluate the impact of clutter diversity on the detection performance. The results highlight that clutter statistical diversity has a strong impact on the detection performance. In the case of two channels, a significant result is that the same value of the probability of detection is obtained for different couples of the shape parameters associated to the two channels. The performances of both single channel and multichannel detection schemes are evaluated on the sea clutter data collected by the NetRAD nodes, in order to evaluate which channel, between the bistatic and monostatic ones, is more favorable for radar detection. Furthermore, the gain, achieved by using a multistatic detection algorithm, is analyzed.