Calibration of a 2D Scanning Radar and a 3D Lidar

In search and rescue applications, mobile robots have to be equipped with robust sensors that provide data under rough environmental conditions. One such sensor technology is radar which is robust against low-visibility conditions. As a single sensor modality, radar data is hard to interpret which is why other modalities such as lidar or cameras are used to get a more detailed representation of the environment. A key to successful sensor fusion is an extrinsically and intrinsically calibrated sensor setup. In this paper, a target-less calibration method for scanning radar and lidar using geometric features in the environment is presented. It is shown that this method is well-suited for in-field use in a search and rescue application. The method is evaluated in a variety of use-case relevant test scenarios and it is demonstrated that the calibration results are accurate enough for the target application. To validate the results, the proposed method is compared to a target-based state-of-the-art calibration method showing equivalent performance without the need for specially designed targets.