This paper is a first introduction to the concept of using Global Navigation Satellite Systems (GNSS) as illuminators of opportunity in a passive bistatic real-time radar system for maritime target indication applications. An overview of the system concept and the signal processing algorithms for Moving Target Indication (MTI) is provided. To verify the feasibility of the system implementation as well as test the developed signal processing algorithms, an experimental test bed was developed and the appropriate experimental campaign with the new Galileo satellites and a ferry as the target was carried out. The results confirm the system concept and its potential for multi-static operation, with the ferry being detected simultaneously by two satellites.

No abstract

This paper addresses the exploitation of GNSS as opportunistic sources for the joint detection and localization of vessels at sea in a passive multistatic radar system. A single receiver mounted on a proper platform (e.g., a moored buoy) can collect the signals emitted by multiple navigation satellites and reflected from ship targets of interest. This paper puts forward a single-stage approach to jointly detect and localize the ship targets by making use of long integration times (tens of seconds) and properly exploiting the spatial diversity offered by such a configuration. A proper strategy is defined to form a long-time and multistatic range&Doppler (RD) map, where the total target power can be reinforced with respect to, in turn, the case in which the RD map is obtained over as a short dwell and the case in which a single transmitter is employed. The exploitation of both the long integration time and the multiple transmitters can greatly enhance the performance of the system, allowing counteracting the low power budget provided by the considered sources representing the main bottleneck of this technology. Moreover, the proposed singlestage approach can reach superior detection performance than a conventional two-stage process where peripheral decisions are taken at each bistatic link and subsequently the localization is achieved by multilateration methods. Theoretical and simulated performance analysis is proposed and also validated by means of experimental results considering Galileo transmitters and different types of targets of opportunity in different scenarios. Obtained results prove the effectiveness of the proposed method to provide detection and localization of ship targets of interest.

The exploitation of the Global Navigation Satellite Systems (GNSS) as transmitters of opportunity in passive radar systems for maritime surveillance is particularly attractive because of the main advantages consisting in a global coverage (even in open sea) and in the availability of multiple sources (different satellites and constellations). The main drawback stays in the restricted power budget provided by navigation satellites. This makes necessary to conceive, define and develop innovative moving target detection techniques specifically tailored for the system under consideration, in order to make this technology a powerful tool for persistent surveillance of sea areas of interest. To this aim, a long integration time Maritime Moving Target Indication technique is proposed in this work, and its effectiveness is proved against experimental data involving a small maritime target, not detectable by conventional MTI techniques. Obtained results prove the feasibility of a maritime MTI mode for GNSS based passive systems.

The availability of new high-resolution radar space-borne sensors offers new interesting potentialities for the acquisition of data useful for the generation of Digital Surface Models (DSMs). Two different approaches may be used to generate DSMs from Synthetic Aperture Radar (SAR) data: the interferometric and the radargrammetric one. At present, the importance of the radargrammetric approach is rapidly growing due to the new high-resolution imagery [up to 1 m Ground Sample Distance (GSD)] which can be acquired by COSMO-SkyMed, TerraSAR-X and RADARSAT-2 in SpotLight mode. The defined and implemented model is related to COSMO-SkyMed SpotLight imagery in zero-Doppler geometry; it performs a 3-D orientation based on two range and two zero-Doppler equations, allowing for the least squares estimation of some calibration parameters, related to satellite position and velocity and to the range measure. The model has been implemented in SISAR (Software per Immagini Satellitari ad Alta Risoluzione), a scientific software developed at the Geodesy and Geomatic Institute of the University of Rome "La Sapienza". Starting from this model, based on a geometric reconstruction, also a tool for the Rational Polynomial Coefficients (RPCs) generations has been implemented. To test the effectiveness of the new model, a stereo pair over the test sites of Merano (Northern Italy) has been orientated using the rigorous model and the RPCs one, and first results of radargrammetric DSM generation are presented; they display the possibility to reach an overall average accuracy of 3.5 m

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document.When citing, please reference the published version. Take down policyWhile the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

This paper investigates the feasibility of using the Global Navigation Satellite Systems (GNSS) as transmitters of opportunity in a passive bistatic radar system for maritime target detection applications. To this purpose, the experimental test bed was developed, and the practical campaign was conducted for maritime data acquisition with the new Galileo satellites and a ferry as the target. By developing and applying the appropriate signal processing algorithm, the obtained experimental results have not only verified the system performance, but also showed the potentialities of a multi-static configuration utilising multiple satellites simultaneously.

No abstract