Abstract: Detection means having thin wire electrodes that are placed on the outer surface of a radome that shelters an antenna used for transmitting and/or receiving intelligence in the form of radio waves, such as those microwave signals used in radar, especially radar that is used for a vehicle. The thin wire electrodes are placed on the radome surface in a way which will not change antenna characteristics. The electrodes measure the electrical resistance of the obstruction material, such as wet mud, that may find its way onto the outer surface of the radome during the operation of the vehicle and that may reduce the sensitivity of the radar's receiver so as to prevent it from recognizing otherwise discernable echo information. The detection means, upon detecting a predetermined electrical resistance of the obstruction material, provides a signal that is routed to the operator that is indicative that the radar performance may have degraded beyond an acceptable limit.

Abstract: A road vehicle radar system for discriminating between hazard and non-hazard targets within a predetermined zone uses a pair of frequency modulated continuous wave radar cycles (FM-CW) and a single continuous wave cycle (CW) in the generation of radar quantities for measuring target range and apparent target velocity. Measured quantities from the FM-CW and CW cycles are compared with predetermined quantities for discriminating between hazard and non-hazard targets.