Abstract: The present invention provides a method and apparatus to determine the position, velocity and orientation of an object with respect to an observation point. It consists of placing a sensor spaced from the object and placed at the observation point which will emit two non-parallel beams of light toward the object. Retroreflectors on the object will reflect the light in opposite direction to generate pulses of reflected light caused by the angular relative motion between the incident beam of light and the retroreflectors. A processor can be used to provide an indication of the position, velocity and orientation of the object based on the time interval between reflected pulses.