Passive radar has reached a state of relative maturity for what concerns stationary sensor operations, widely proving their ability to detect, localize and track air and ground targets exploiting the signals transmitted by different kinds of illuminators of opportunity (e.g. FM radio, DAB, DVB-T, DVB-S). The extension of passive radar technology to the case of mobile platforms represents an emerging research area and opens new perspectives in the framework of both defense and civil surveillance applications. However, the potential strategic advantages offered by a passive radar mounted on a moving platform are paid in terms of motion induced Doppler distortions of the received signal, which can adversely affect system performance. Specifically, a proper suppression of the Doppler-spread backscattering from the stationary scene is typically required in order to detect moving targets with small radial velocity components, otherwise appearing as buried into clutter. This can be achieved by exploiting systems with multiple receiving channels, enabling space-time processing. The proposed activity aims at developing innovative signal processing techniques and operational strategies, tailored for multichannel mobile passive radars and aimed at detection and localization of moving targets. Several potential scenarios will be considered for bistatic radar application, such as air, ground, and maritime surveillance, from ground-based or airborne moving platforms. The potentialities offered by parasitic exploitation of DVB-T transmitters will be mostly investigated and experimental campaigns are expected to be planned in order to test the developed techniques.
Moving passive radar is indeed a new and complex topic. The passive radar technology has already reached a maturity state for what concerns stationary sensors and is moving fast from the research and academic area of technological demonstrators to the industrial prototypes and final products. On the other hand, the applications of passive radar to moving platforms is still a relatively unexplored field. We strongly believe that the same previous paradigm could be replicated in this new topic.
As described in the previous section, the first results have been presented on moving passive radar, exploiting DVB-T illuminators. In this project, our proposal is to extend these results by developing novel signal processing technics to enhance clutter removal, moving target detection, and position estimation in a mobile passive radar configuration. Therefore, we have planned the exploitation of multichannel system configuration and adaptive space-time algorithms. In addition, a target localization stage could also be implemented using this framework, which will represent a novel result. Moreover, we will explore the impact on the ambiguity function of using the Reciprocal Filter with signal fragmentations different from OFDM symbols for DVB-T signals, which has still not been investigated in the literature.
With the results obtained by this research activity, we will hopefully contribute to paving the way for a full operational capability of passive radar sensors onboard moving platforms in the next future.