IoSiS – A high performance experimental imaging radar system for space surveillance

Abstract

The Microwaves and Radar Institute of German Aerospace Center (DLR) has developed and constructed an experimental radar system called IoSiS (Imaging of Satellites in Space), being presently still in the commissioning phase. The overall goal of that system is research on concepts for advanced acquisition of high-resolution radar images of objects in a low earth orbit (LEO). Such images can allow the analysis of complex satellite structures for detection of possible mechanical damages or irregularities generated by space debris, for example. Furthermore investigations on unknown space objects or satellites can be performed. Based on inverse synthetic aperture radar (ISAR) geometry, a ground-based radar produces high-resolution range profiles along a certain azimuth angle by tracking the space object using a steerable antenna system. Steered tracking of objects during overpass, whose trajectories have to be sufficiently known, allows a very wide range of azimuth observation angle. Thus high azimuth resolution in the order of the range resolution can be achieved, depending on center frequency and bandwidth. The IoSiS range resolution is given by the radar bandwidth of up to 4.4 GHz, being in theory up to few centimeters. This paper outlines the system design of IoSiS. Elementary processing steps from raw data to the final ISAR image of a space object are discussed. Finally, a measurement result of the International Space Station (ISS) is shown as an example.