Abstract: A very low-cost, short-range electromagnetic transceiver uses a low frequency oscillator signal as a means of charging a step recovery diode (SRD) which converts the stored charge into a very short impulse to enable very high energy efficiency frequency multiplication. This impulse is coupled to an antenna which radiates the energy and receives reflections from objects in the vicinity. The energy of the received impulse reflections in an indicator of the distance of the object to the sensor. This system may be used in a vehicle to detect obstructions in its path of motion or a parking facility where it would determine the occupancy of each vehicle parking space. In the parking facility embodiment, information is reported to a central office computer which displays spaces which are not occupied and available for assignment.