The paper examines the problem of cancellation of direct signal, multipath and clutter echoes in passive bistatic radar (PBR). This problem is exacerbated as the transmitted waveform is not under control of the radar designer and the sidelobes of the ambiguity function can mask targets including those displaced in either (or both) range and Doppler from the disturbance. A novel multistage approach is developed for disturbance cancellation and target detection based on projections of the received signal in a subspace orthogonal to both the disturbance and previously detected targets. The resulting algorithm is shown to be effective against typical simulated scenarios with a limited number of stages, and a version with computational savings is also introduced. Finally its effectiveness is demonstrated with the application to real data acquired with an experimental VHF PBR system.

The presence of clutter in passive radar returns imposes a minimum floor level on the ambiguity surface, masking weak returns and reducing dynamic range. When the illuminating signal is a form of OFDM, orthogonality between subcarriers can be exploited to produce a zero floor within certain delay bins. In this paper we compare and contrast several such ambiguity processing techniques for general OFDM signals. The methods are applied to simulated and real DVB-T passive radar returns having a wide range of delays. It is shown that an OFDM-specific method can outperform a standard pulse-Doppler processing method under certain conditions. An example is provided using real German DVB-T data from Fraunhofer FHR.

A MFH-PR concept has been presented. The rationale for pursuing such a hybrid unit has been explained in terms of enhancing detection range and coverage over conventional PRs. The important distinctions between MFNs and SFNs have been analysed. Section VI has described the advantages of signal reconstruction and has shown that, in certain situations, adequate interference suppression can be achieved without use of additional adaptive filters. An important consideration of MFH-PR is the potential range coverage extension. This has been demonstrated in Section VII using an advanced radar planning tool. Frequency and spatial diversity have been discussed in the context of improving tracking performance. The military utility of a MFH-PBR has also been discussed in Section XIII.

We present a system characterisation of a passive bistatic radar (PBR). The system under investigation exploits dasiailluminators of opportunitypsila, which in this case are commercial, non-cooperative, VHF FM broadcast transmissions. The PBR under investigation demonstrates the detection of large passenger-jet aircraft in the airspace over greater London. FM based PBRs such as the type examined here have been shown to be effective at remote sensing of auroral turbulence, density irregularities in the E-region and F-region of the ionosphere and meteor trails. Detection of aircraft is an important step in attempting to remotely sense outer-atmospheric phenomena as aircraft scattered power is of a comparable magnitude and similar Doppler frequency to the natural phenomena described. This paper also analyses the merits of FM broadcast transmissions for use as radar signals. A system characterisation with performance predictions is presented. The results show that target detections have been achieved to ranges in excess of 70 km (bistatic range). Multiple broadcast channels from two different transmitters of opportunity enhance the case for deciding whether or not targets are present. Air-truth data provided by a mode S/ADS-B IFF receiver is used for comparison with the 2-D bistatic results.

In this paper we examine an FM based PCL radar system and attempt to quantify its performance in the presence of various different jamming waveforms namely broadband noise and a single tone on the carrier. It is shown that effective jamming can be achieved with relatively low jamming power. The importance of an effective direct signal canceller is also shown as a means of suppressing the jamming signal. The effect of these jamming scenarios is shown through simulation and then compared to a representative measured result from a real FM based PCL radar system.

This study examines ground and sea clutter from three different FM‐based passive bistatic radars (PBRs). Measurement data has been obtained for low‐grazing angles. The PBRs used to collect the displayed data, with all their relevant parameters, are defined and clutter analysis procedures are described. This work, based on measured data, yields valuable insight into the nature of VHF bistatic clutter.