An apparatus, and method of operating the same processes of LADAR data including iterating back and forth between target detection in a 2-D array having range and range rate dimension, and a 4-D array having azimuth, azimuthal velocity, elevation, & elevation velocity dimensions. The apparatus includes a receiver and a processor arranged to generate photo events including target signal photo events and background photo events, transform the photo events into the 2-D target tracking array including range and range-rate parameters and tag photo events determined to be 2-D target signal photo events. The processor transforms tagged photo events into the 4-D target and tags photo events determined to be 4-D target signal photo events.