DVB-T Signal Ambiguity Function Control for Passive Radars

Abstract

The use of digital video broadcasting-terrestrial (DVB-T) signals as waveform of opportunity for passive coherent location (PCL) is addressed here. The ambiguity function (AF) of the considered waveform of opportunity has been shown to yield regularly spaced undesired peaks which might strongly limit the target detection capability of a DVB-based PCL system. A new technique for DVB-T AF control is proposed, able to overcome the limitations of previously proposed approaches in terms of achievable performance, system requirements, and computational burden. The performance analysis against simulated and real data shows that the proposed technique yields an effective removal of the undesired peaks in the AF thus making the considered waveform more attractive for PCL surveillance

Mixed Signal-Based GLR Detector for Fm Passive Bistatic Radar Target Detection

“…In this section, firstly the conventional signal model for PBRs according to [1][2][3][4][5][6][7][8][9][10][11][12] is introduced. Then, the mixed signal model which is the case in this paper is discussed.…”

“…Passive bistatic radar (PBR) systems, using existing transmitters as transmitters of opportunity, have been vastly studied in recent years [1][2][3][4][5][6]. Since the transmitted signal is not known for the PBR systems, a dedicated channel referred to as the reference channel is used for the reception of the directly transmitted signal.…”

Multi-Frequency Target Detection Techniques for DVB-T Based Passive Radar Sensors

“…Such a filtering stage is intended to remove the high side-lobes and spurious peaks appearing in the DVB-T signal ambiguity function (AF) [3]. To this end we resort to the linear approach presented in [9] which is based on the cascade of the pilot signals’ equalization and a Residual Peaks Removal (RPR) filter to remove the zero-Doppler peaks. Notice that, when we are interested in slowly moving target detection, the pilots equalization stage can be neglected as it allows removal of the side-peaks appearing at quite high Doppler values.…”

“…Nowadays the transmissions for Digital Video Broadcasting-Terrestrial (DVB-T) represent one of the most attractive choices as they offer a quite stable range resolution of about 20 m (equivalent monostatic value) thanks to the orthogonal frequency division multiplexing (OFDM) modulation based on persistent sub-carriers that span a total bandwidth of up to 8 MHz. Moreover, by employing an OFDM modulation, the DVB-T signals are noise-like waveforms, thus, they provide more attractive ambiguity function properties that are nearly independent of the signal content and almost time-invariant [3,4,5,6,7,8,9]. …”

“…With reference to the first application, the performance of such systems suffers from the vertical-plane radiation patterns of typical DVB-T transmitters that are tailored to avoid wasting too much power above the horizontal plane. In fact DVB-T-based PR has been shown to allow a reliable detection capability, mainly against targets flying at low altitude, at distances up to tens of kilometers [8,9,10,11,12,13,14,15]. Therefore, such sensors can be fruitfully integrated, with the role of gap-fillers, within conventional ATC solutions to provide continuous coverage.…”