The exploitation of existing satellite transmissions for passive bistatic radar applications is now an emerging area due to well-known advantages as global coverage, reliability of the transmission, availability of multiple sources and existing information on signal characteristics. For these reasons space-based transmitters as illuminators of opportunity are of special appealing for maritime and air surveillance applications. The considered satellites were originally built for other purpose, therefore the power budget is suitable for telecommunication applications but it is very low for radar application. To overcome such limitation, the proposed activity has the main goal of studying and developing innovative techniques specifically tailored for the system under consideration able to detect, extract feature and estimate the kinematic parameters for maritime and aerial targets. Among the enormous set of orbiting systems: (i) Global Navigation Satellite Systems (GNSS) is exploited for the maritime targets detection and (ii) geostationary satellites are used for air targets. In particular, to overcome the problem of low power density with regard to the first point a processing technique able to integrate over long time intervals is proposed, meanwhile for the second point the forward scattering concept is investigated.
The exploitation of satellites already existing for other purposes is obtaining an increasing interest for surveillance applications. In this frame, the principal aim of the proposed activity is to study and develop innovative techniques for target (aircrafts, ships) detection and motion parameters estimation. In the field of maritime security, information as ships position and size are fundamental to monitor maritime traffic. In the framework of GNSS-based passive radar for maritime surveillance, as discussed above, the feasibility of using GNSS signal backscattered from the surveyed area has been demonstrated in [6] and a novel processing technique for ship detection particularly designed for the system under consideration has been presented in [7]. Our research is focused on the study and validation of this innovative detection technique on synthetic/experimental datasets. Our further objective is to study and define a new methodology to extract object features (size, length) and validate it on synthetic/experimental datasets. In the field of aerial targets detection, as mentioned previously, the potentialities of the FSR passive radar systems in the far field area have been investigated in different works. In this frame the core of the research is the development of detection and motion parameters estimation techniques through geostationary satellites as illuminators of opportunity. In [11] we have presented preliminary experimental results related to an ad hoc acquisition campaign carried out near "Leonardo Da Vinci" airport of Rome where HotBird 13D is the satellite selected from the geostationary satellites fleet HotBird 13°E where European television broadcast entrust their transmission. The aim of the acquisition campaign is to detect planes landing at the airport following a certain runway and the feasibility of the DVB-S based FSR configuration for air target detection was shown. The main goal of our work is to extend the proposed approaches to experimental data and to devise new suitable motion parameters estimation techniques. The obtained results in terms of velocity estimation will be compared with the ground truth provided by the ADS-B receiver. The effectiveness and the feasibility of the velocity estimation techniques will be assessed and discussed also by generating synthetic datasets. In this way aiming to give a thorough analysis different target trajectories will be investigated. By this time it is of interest to lay down under which conditions and for which target trajectories the developed motion parameters estimation techniques provides best performance and under which not. Moreover the performance of the developed techniques will be investigated and validated from a theoretical point of view which will allow to define upper bound performance.