Optimum Beamforming to Improve UAV’s Detection Using DVB-T Passive Radars

In this paper, the improvement of the detection capabilities of Passive Radars (PRs) exploiting Digital Video Broadcasting signals for small drone detection is tackled. Beamforming techniques optimized to increase the Signal-to-Interference Ratio (SIR) are applied in a two-stage frequency-domain spatial filtering processing scheme. Real radar data acquired by a technological demonstrator developed at the University of Alcalá were used to validate the proposed solution. The optimum beamforming depends on the interference model. Considering the Cross-Ambiguity Function (CAF) output as the input space, a statistical analysis of clutter return was carried out for each array element. Results proved that clutter statistics depend on the array element, and are a function of the Doppler shift in the CAF area close to the zero Doppler, so optimum beamforming weights are estimated for each Doppler region and array antenna. Detection performance evaluation confirmed the expected improvement in SIR and its positive impact in small drone detection.