As recently demonstrated, passive radars are able to detect and track targets by exploiting illuminators of opportunity. In this paper, it will be proven that the same concept can be extended to passive inverse synthetic aperture radar (P-ISAR) imaging. A suitable type of signal processing is proposed that is able to form P-ISAR images starting from range-Doppler maps, which represent the output of passive-radar signal processing. Multiple-channel digital television broadcasting (DVB)-T signals are used to demonstrate the concept as they provide enough range resolution to form meaningful ISAR images. The problem of grating lobes, which are generated by the DVB-T signal, is also addressed and solved.

Passive bistatic radar or passive coherent location is gaining interest in the radar community, as it provides some advantages with respect to active radar. Passive radar does not aim to replace active radar; it provides a good complement to it. The computational effort that is required to implement the required signal processing is one of the drawbacks that affect passive radars. In this paper, a suboptimal but computationally affordable detection algorithm is investigated that is applicable to arbitrary waveforms (different types of illuminators of opportunity). First, a detailed mathematical formulation of the proposed suboptimum algorithm is derived. A theoretical performance analysis is then provided based on a comparison of the proposed with the optimum two-dimensional matched filter. Finally, simulated and real data are used to demonstrate the effectiveness of the proposed algorithm and to validate the theoretical performance analysis.

The exploitation of multiple DVB-T channels for a passive radar system has been considered to enhance the radar range resolution. A preliminary study has focused on the AF analysis to verify the suitability of a multichannel DVB-T signal for radar applications. The theoretical study has been supported by preliminary measurements relative to three adjacent DVB-T channels. Experimental results in an aerial scenario through the use of SDR hardware have been carried out and showed a clear improvement in range resolution when using multichannel rather than single channel DVB-T signals. It may be proven in the near future that target classification of noncooperative target radar imaging will be enabled by a high resolution DVB-T passive radar that is obtained by exploiting multichannel DVB-T signals.

The purpose of the paper is to show how the Universal Software Radio Peripheral (USRP) technology, typically used for implementing telecommunication systems, can be used for realizing passive radars. Specifically in this paper a multiband passive radar is considered. A preliminary study on the signals of opportunity is presented where real and simulated radar ambiguity functions have been evaluated. An experimental system has been set up and live data acquired both for UMTS and DVB-T signals in order to verify the capability of the proposed passive radar demonstrator.

In a maritime domain awareness scenario, two main areas of interest can be recognized, specifically harbour protection and navigation safety. Harbour protection is currently a main concern and it is aimed at controlling the risk associated with possible attacks or illegal activities which can take place in the marine access areas. On the other hand, the objectives of the navigation safety are essentially connected to achieve an improved maritime navigational awareness by providing information on collision avoidance and general guidance to the navigators [1].