Abstract: The specification discloses a radar sensor for detecting short-range, slowly moving objects and using the range versus time data to develop a prediction of the time at which the range of the object will be at a minimum to the sensor. The sensor uses a pulse transmission of a radio frequency signal with object reflections being received and detected. Subsequent signal processing eliminates returns from clutter and stationary objects so that signals from low velocity objects can be detected. Computations are performed in a digital processor to compute an estimate of the time and of the range when the object will be closest to the sensor.