A MILLIMETER WAVE PASSIVE RADIOMETER TO DETECT TARGETS AT SEA

WE PROPOSE A PASSIVE MULTI-CHANNEL MILLIMETER-WAVE RADIOMETER FOR DETECTING METAL OBJECTS AGAINST THE SEA-SURFACE BACKGROUND, EVEN THOUGH THE TARGET IS TOO SMALL TO BE BEAMFILLING. THE PROPOSED "FREQUENCY-TRANSFORMATION" DETECTION TECHNIQUE WILL UTILIZE MULTIPLE PASSIVE CHANNELS AT 23, 31,, AND 94 GHZ. THIS RADIOMETER DEVELOPMENT TO DETECT TARGETS AT SEA IS A LOGICAL EXTENSION OF OUR ALREADY DEVELOPED AND COMMERCIALLY AVAILABLE 23/31 GHZ WATER VAPOR RADIOMETER. THE PROPOSED RADIOMETER, UNLIKE CONVENTIONAL RADAR, IS PASSIVE AND THUS DOES NOT REVEAL ITS LOCATION BY GIVING OFF ANY ACTIVE RADIATION. IT WOULD BE EXTREMELY DIFFICULT TO ACTIVELY JAM SINCE IT DETECTS THE RELATIVE ABSENCE OF NATURAL THERMAL MICROWAVE ENERGY CAUSED BY SKY REFLECTIONS OFF METAL TARGETS. ANY ACTIVE JAMMER COULD ITSELF BE TARGETED VIA ITS EMISSION, AND WOULD HAVE TO SIMULATE A WIDE AREA DIFFUSE SOURCE FROM A POINT TRANSMITTER.