Advanced Buried Object Detection by Multichannel, UAV/Drone Carried Synthetic Aperture Radar

The great innovations of Synthetic Aperture Radar (SAR) technology during the past years stimulated new applications in several areas. While in the past SAR was primarily operated for airborne and spaceborne applications, novel operations for quite low altitude like surveillance of cities, local agricultural applications, or even buried object detection, are of new interest. For such operations the well-known and established SAR system concepts should apply similarly, while the technology has to be transferred to the state of the art and new platforms like unmanned aerial vehicles (UAVs) or drones. The paper addresses the special concept for a SAR to detect buried mines. It combines a novel DLR approach based on multistatic observation with the capability to create nearly arbitrary azimuth sampling trajectories. By providing very high resolution it is possible to even identify man-made objects like landmines in the SAR image by their spatial radar-cross section (RCS) distribution. These capabilities allow advanced detection capabilities and satisfy the ultimate demand for buried object identification, both being great improvement in landmine detection and related activities. Beside this concept the paper addresses an idea on robust high-precision positioning, which is indispensable for a successful SAR system. It is based on a photogrammetric method providing the trajectory, the orientation of the UAV and the three-dimensional (3D) ground surface as a side effect as well. Measurement results are shown confirming the feasibility of the proposed approach.