Abstract: A radar system for sensing the presence of obstacles in a vehicle's "blind spots" and generating a signal to the vehicle operator indicative of the presence of such an obstacle. The system uses a common radar transceiver that transmits a multi-frequency radio signal directed at a blind spot of the vehicle. The signal is reflected off any obstacles that are present in that blind spot region. Doppler shifts in the received reflected multi-frequency signal generally indicates that an obstacle has moved into the blind spot. Doppler frequencies attributable to objects which are of no interest, such as stationary objects, are filtered out. The system has a signal processor which determines if a potentially hazardous object is within a pre-determined range from the vehicle.