DVB-S Based Passive Polarimetric ISAR—Methods and Experimental Validation

Abstract

In this work, we focus on passive polarimetric ISAR for ship target imaging using DVB-S signals of opportunity. A first goal of the research is to investigate if, within the challenging passive environment, different scattering mechanisms, belonging to distinct parts of the imaged target, can be separated in the polarimetric domain. Furthermore, a second goal is at verifying if polarimetric diversity could enable the formation of ISAR products with enhanced quality with respect to the single channel case, particularly in terms of better reconstruction of the target shape. To this purpose, a dedicated trial has been conducted along the river Rhine in Germany by means of an experimental DVB-S based system developed at Fraunhofer FHR and considering a ferry as cooperative target. To avoid inaccuracies due to data-driven motion compensation procedures and to fairly interpret the polarimetric results, we processed the data by means of a known-motion backprojection algorithm obtaining ISAR images at each polarimetric channel. Then, different approaches in the polarimetric domain have been introduced. The first one is based on the well-known Pauli Decomposition. The others can be divided in two main groups: (i) techniques aimed at separating the different backscattering mechanisms, and (ii) image domain techniques to fuse the polarimetric information in a single ISAR image with enhanced quality. The different considered techniques have been applied to several data sets with distinct bistatic geometries. The obtained results clearly demonstrate the potentialities of polarimetric diversity that could be fruitfully exploited for classification purposes.

Inverse Synthetic Aperture Radar Imaging: A Historical Perspective and State-of-the-Art Survey

“…However, it is computationally very intensive when combined with a data-driven motion estimation method (usually including numerical optimization). Thus, BP has so far been mostly limited to imaging of cooperative targets, where the target motion is known a priori [186]- [190].…”

“…This is because range compression and clutter cancellation require a more sophisticated approach. More recently, a number of passive ISAR experiments using digital television (DTV), digital video broadcasting (DVB-T and DVB-S) signals have been reported in [190], [268]- [273].…”

First experimental results on multi-angle DVB-S based passive ISAR exploiting multipolar data

“…Polarimetric decomposition methods are usually applied to recognize the scattering processes produced by the observed object, providing meaningful information for classification procedures [17]. In [12], a first investigation on the capability of DVB-S based passive polarimetric ISAR to separate the scattering mechanisms has been provided, showing that different target structures behave differently in the polarimetric domain.…”

“…Scattering mechanisms are sensitive to the polarization states of the e. m. radiation, thus allowing for a much richer information set to be garnered from which target classification can be improved. DVB-S transponders are overlapped and interleaved in the horizontal (H) and vertical (V) polarizations, therefore multipolar passive ISAR imaging is fundamentally possible [12].…”

Parasitic Surveillance Potentialities Based on a GEO-SAR Illuminator

“…A suitable solution is represented by Global Navigation Satellite Signal (GNSS) constellations: for many years their opportunistic exploitation has been well known by the remote sensing community for reflectometry [16] and passive SAR [17] applications, and, more recently, their alternative utilizations for passive coherent locations have also been explored [18][19][20]. Other noteworthy options are represented by communication satellites such as Iridium and Inmarsat [21], and broadcast systems such as DVB-S transponders [22][23][24].…”