SUMIRAD: a low-cost fast millimeter-wave radiometric imaging system

For many military or peace-keeping operations it is necessary to provide better situational awareness to the commander of a vehicle with respect to possible threats in his local environment (predominantly ahead), at a distance of a few ten to a few hundred meters. Such a challenging task can only be addressed adequately by a suitable multi-sensor system. As a beneficial part of that, an imaging radiometer system with a sufficiently high frame rate and field of view is considered. The radiometer, working 24 hours in all weather and sight conditions, generates quasi-optical images simplifying the microwave image interpretation. Furthermore it offers the advantage to detect and localise objects and persons under nearly all atmospheric obstacles and also extends the surveillance capabilities behind non-metallic materials like clothing or thin walls and thin vegetation. Based on constraints of low costs and the observation of a large field of view, the constructed radiometer still offers a moderate resolution at a moderate scan speed. This paper describes the challenges for the design of a vehicle-based imaging radiometer system at W band, providing high-quality images of sufficient resolution for a large field of view at a moderate frame rate. The construction is briefly outlined and imaging results for several situations are presented and discussed. Those comprise measurements on target detection and a visual comparison of different SUM (Surveillance in an Urban environment using Mobile sensors) data products.