Multilook Processing Scheme in DVB-T Based Passive SAR Applications

In this paper, digital video broadcasting (DVB-T) transmitters are considered for passive SAR imaging of ground scenarios. A multilook processing scheme is proposed to reduce image noise, to improve the interpretation of the radar image and to make possible the correct detection and area delimitation of scattering targets in the radar scene. A measurement campaign was carried out to analyse and validate the proposed processing scheme. A DVB-T based passive radar was mounted in an EADS CASA C-295M aircraft to generate the synthetic aperture of the receiver. The acquired data was processed under different passive imaging configurations to analyse the radar image quality improvement of multilook processing scheme. Results show the reduction of image noise and the high increase of targets boundaries identification that can be used as a starting point for carrying on further passive SAR scattering characteristics analysis.

I. Introduction

Synthetic Aperture Radar (SAR) is a widely used and well-established technology for active radar imaging of the surface of the Earth. Multiple systems have been developed using airborne (ie. F-SAR, SAR AERO) and satellite plat-forms (ie. Terrasar X, PAZ, ICEYE). In comparison, passive SAR systems that use non-cooperative radio transmitters as Illuminators of Opportunity (IoOs), such as radio FM or digital broadcasting television (DVB-T), have emerged in recent years at different research institutions. The concept of DVB-T passive SAR imaging based on airborne systems has been validated in several independent research work [1]–[4]. Whereas the deployment of space-borne satellite receivers was proposed to perform passive SAR imaging based on DVB-T signals in [5], being the concept validated on airborne-based passive SAR measurements. The effects of the bistatic angle on imaging performances were analysed in [6].