An ultra wideband radar system for detecting objects where at least one of the radar system or the object is moving. The radar may be scanned in at least one dimension, which may include angle or range. The system includes a scan combiner that combines scan information in accordance with a trajectory characteristic of a moving object and/or of a moving platform on which the radar resides. Scans may be combined by integration or filtering. A fast calculation method is described wherein the scans are combined into subsets and subsets are shifted in accordance with the trajectory characteristics before further combination. The scan information is combined in accordance with trajectory characteristics to enhance the object signal to noise. Further features are described wherein the scan information is combined according to a family of candidate trajectories and/or object positions.