LOW-COST FM-CW DOPPLER MICRO-RADAR RAIN GAGE

NEW NASA SATELLITE REMOTE SENSING PROGRAMS SUCH AS TRMM, WHICH INTEND TO MEASURE GLOBAL PRECIPITATION, REQUIRE "GROUND TRUTH" CALIBRATION. PRECIPITATION MEASUREMENT IS ESPECIALLY DIFFICULT FROM SHIPS AT SEA, WHICH ARE THE PRIMARY "SEA TRUTH" AVAILABLE OVER MOST OF THE EARTH'S SURFACE. CONVENTIONAL GAGES ARE UNSUITED TO MARINE PLATFORMS. IF SUCCESSFUL, THIS RESEARCH WILL RESULT IN A PRACTICAL AND INEXPENSIVE PRECIPITATION GAGE BASED ON MINIATURE FREQUENCY MODULATED CONTINUOUS WAVE (FM-CW) DOPPLER RADAR TECHNOLOGY. IT WOULD BE SUITED TO SHIPBOARD OR NORMAL SURFACE USE. BASED ON OUR DEMONSTRATION HARDWARE DOCUMENTED IN THIS PROPOSAL, WE BELIEVE THE MICROWAVE RADAR TRANSMITTER AND COHERENT DOPPLER HETERODYNE DETECTOR FRONT END COULD BE FABRICATED FOR A TOTAL COMPONENT COST OF LESS THAN $400 AT KBAND AND FOR LESS THAN $200 AT X BAND. THE POTENTIAL LOW COST OF OUR PROPOSED HARDWARE RESULTS FROMRECENT DEVELOPMENTS IN MICROWAVE COHERENT HETERODYNE FM TECHNOLOGY, AS WELL AS COMMERCIAL ECONOMIES OF SCALE ATTAINED BY POLICE RADAR, MICROWAVE BURGLAR ALARMS, AND DOOR-OPENER LARGE SCALE MANUFACTURING. WE PROPOSE TO APPLY THESE DEVELOPMENTS TO A METEOROLOGICAL DOPPLER RADAR. THE RESULT SHOULD BE A MINIATURE DOPPLER RADAR PRECIPITATION GAGE AT A COST APPROACHING THAT OF A CONVENTIONAL RAIN GAGE.