Adaptive Target Detection Techniques for OFDM-Based Passive Radar Exploiting Spatial Diversity

Gilles Chabriel (1) , Jean Barrère (1)

1 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence

Recently, it has been studied the benefit of using a channel-based detector (CHAD) with a passive radar exploiting OFDM waveforms radiated e.g. by DVB-T transmitters of opportunity. When multiple antennas are available on receive, we state that CHAD can be seen as space-time array-processing performing on a particular coherent frequency datacube. Building on this new interpretation, we propose an improved version of CHAD in the form of a fully dimensional space-time adaptive processing. Optimization of the signal-to-interference-plus-noise ratio is obtained combining a linearly constrained minimum variance (LCMV) space-time adaptive beamforming and a least squares (LS) spatial adaptive filtering. Unlike classical STAP approaches, no training data are here used and only one space-time sample matrix inversion is required. The computational load is then highly reduced allowing a practical deployment. Moreover, since no beamscan in space is performed, the knowledge of array characteristics is not required and the performance shall not be impacted by any calibration errors. Finally, the full set of target signal returns being collected in a single range-Doppler surveillance map, the detection process is then simplified. Results on experimental data show the interests of this new surveillance scheme: no need for a prior rejection of the dominant interference, systematic reduction of secondary lobes, discrimination of slow moving targets.

Mots clés: passive bistatic radar (PBR); passive covert radar (PCR); passive coherent location (PCL); digital video broadcasting-terrestrial (DVB-T); orthogonal frequency division multiplexing (OFDM); spatial diversity; cross-ambiguity function (CAF); matched filtering; mismatched filter; reciprocal filter; clutter; linearly constrained minimum variance (LCMV) beamform- ing; CAPON’s receptor; array-processing; space-time adaptive processing (STAP); least squares (LS) filtering

Domaines: Traitement du signal et de l'image [eess.SP]

Gilles Chabriel, Jean Barrère. Adaptive Target Detection Techniques for OFDM-Based Passive Radar Exploiting Spatial Diversity. IEEE Transactions on Signal Processing, 2017, 65 (22), pp.5873 - 5884. ⟨10.1109/TSP.2017.2742980⟩. ⟨hal-01790695⟩