Simon Anger, German Aerospace Center (DLR); Florian Bischeltsrieder, German Aerospace Center (DLR); Matthias Jirousek, German Aerospace Center (DLR); Fabian Hochberg, German Aerospace Center (DLR)
https://doi.org/10.64861/DWFI1267
Keywords: Radar imaging, Inverse synthetic aperture radar, ISAR, IoSiS, Space situational awareness, high-resolution, radar system
Abstract:
In view of the increasing number of space objects, comprehensive high-quality space surveillance becomes ever more important. Together with the enormous amount of space debris, satellites are at risk of being destroyed or at least severely damaged. In addition to detecting damage to satellites more and more unknown satellites are orbiting the Earth for which image-based reconnaissance is mandatory. Radar is a powerful tool that, in addition to detection and tracking of objects, also enables high-resolution imaging independent of daylight and most weather conditions. The technique of Inverse Synthetic Aperture Radar (ISAR) allows very high-resolution and distance-independent two-dimensional images to be obtained. In cooperation with optical sensors, radar provides a powerful tool for proper space surveillance. The main advantage of using the electromagnetic spectrum at longer wavelengths compared to optical systems, apart from the range-independent spatial resolution of radar, is that the effects of the atmosphere or weather conditions are reduced or even negligible.
Advanced high-performance radar imaging of space objects is a complex and demanding task, touching many technological and signal processing issues. Therefore, besides basic research, the Microwaves and Radar Institute of the German Aerospace Center (DLR) has developed and constructed an experimental radar system called IoSiS (Imaging of Satellites in Space) for developing new concepts for the acquisition of advanced high-resolution radar image products of objects in the low Earth orbit. Based on pulse radar technology, which enables precise calibration and error correction, IoSiS so far has imaged space objects with a spatial resolution in the centimeter range, being novel in the public perception and the accessible literature.
Compared to existing radar-based space surveillance systems, which operate using monostatic large-sized antenna configurations, in future, IoSiS is going to be expanded to include several spatially distributed rather small-sized antennas. This is a crucial factor in being able to image the ever-growing number of satellites in orbit with unprecedented precision. More importantly, the bi- and multi-static capabilities of the future IoSiS system will improve the information content of the images compared to existing monostatic radar images from satellites by providing true three-dimensional (3D) and as well multistatic images of space objects.
Since 2025 the new research facility IoSiS-Next Generation (IoSiS-NG) has been under construction. The facility will comprise two 9-meter Cassegrain antennas and building infrastructure for radar operation, antenna control, and the housing of the radar, electronics and computer equipment. In addition, the unique facility will include mobile antennas for experiments towards bi- and multi-static satellite imaging modes. The setup of the research facility allows addressing key challenges in multistatic satellite imaging using up to kilometer baselines.
Date of Conference: September 15-18, 2026
Track: SDA Systems & Instrumentation