Robust UAV-Borne Fully Digital MIMO OFDM Radar for the Generation of a Digital Elevation Model

The digital elevation model (DEM) recording of a bulk material is preferably done airborne. Optical systems like lidar or photogrammetry are limited when it comes to dusty environments like stockpiles. Radar systems provide a robust and reliable solution to measure a ground surface topography. For use in harsh environments a MIMO OFDM radar with minimal analog hardware is developed. The signal synthesis and evaluation is done by a field programmable gate array. To reduce the requirements on the position accuracy and processing hardware, only the angle estimation for zero-Doppler shift of an 1D-MIMO array is processed and stored. This robust system is independent of the unmanned aerial vehicles tilt angle and can handle a fast flight velocity. To validate the measurement system, multiple measurements of a slope are successfully merged to a single DEM.