A HIGH RESOLUTION: LOW ALTITUDE FLIGHT TEST MINI-SODAR ANEMOMETER GROUND STATION FOR HELICOPTER AND VERTICAL TAKEOFF LANDING AIRCRAFT

MEASUREMENT OF WIND AND TURBULENCE BY REMOTE SENSING TO A HEIGHT OF AT LEAST ONE KILOMETER ABOVE GROUND LEVEL HAS BECOME WELL ESTABLISHED. SUCH SYSTEMS ARE KNOWN AS DOPPLER ACOUSTIC SOUNDING SYSTEMS (DASS) OR SOUND DETECTION AND RANGING (SODAR). THESE SYSTEMS UTILIZE SOUND AT RELATIVELY LOW FREQUENCIES - 1200 TO 2000 HZ. RECENT EXPERIMENTAL WORK HAS SHOWN THAT THE "MINI-SODAR" HAS GREAT POTENTIAL FOR WIND AND TURBULENCE MEASUREMENTS CLOSE TO THE SURFACE (20 - 300 FEET) WITH IMPROVED ACCURACY AND SPACIAL RESOLUTION. USE OF HIGH FREQUENCIES (4000 - 6000 HZ) PERMITS CONSIDERABLY SMALL SIZE, MORE PORTABILITY AND OPERATION IN NOISY SURROUNDINGS. IT IS STRONGLY BELIEVED THAT "A HIGH RESOLUTION, LOW ALTITUDE FLIGHT TEST MINISODAR ANEMOMETER GROUND STATION" CAN BE DEVELOPED FOR HELICOPTER AND VTOL AIRCRAFT BY UTILIZING EXISTING KNOWLEDGE OF SODARS AND ADVANCING THE MINI-SODAR FROM THE EXPERIMENTAL STAGE INTO A COMMERCIAL PRODUCT.