GPS RAWINSONDE DEVELOPMENT

THE METEOROLOGICAL SOUNDING SYSTEM (MSS) USED BY THE NATIONAL RANGES USE A GROUND TRANSMITTING RANGING SYSTEM FOR SPACE POSITION LOCATION OF THE RADIOSONDE INSTRUMENT. SINCE THESE RADIOSONDES USE A BROAD BAND RECEIVER, MULTIPLE RADIOSONDE DEPLOYMENT AND OPERATION IN A GIVEN AREA IS NOT FEASIBLE. THESE RANGING RADIOSONDES ARE ALSO HIGHLY SUSCEPTIBLE TO INTERFERENCE FROM OTHER RF SOURCES AT, OR NEAR, THEIR OPERATING FREQUENCY. SPACE POSITION DATA PROVIDED BY A NAVIGATIONAL AID SYSTEM (NAVAID), SUCH AS GPS, PROVIDES AN EXCELLENT SOLUTION TO THESE PROBLEMS. GPS IS THE BEST SOLUTION FOR SPACE POSITION DATA ACQUISITION OVER ALL OTHER NAVAID SYSTEMS BECAUSE IT IS OPERATIONAL WORLDWIDE, PROVIDES BETTER PRECISION, IS INDEPENDENT OF STATIONS OPERATED BY OTHER GOVERNMENTS, AND IS FREE OF INTERFERENCE FROM ATMOSPHERICS, ETC. NAVSYS CORPORATION HAS A PROPRIETARY DESIGN FOR A LOW-COST GPS SENSOR SUITABLE FOR RAWINSONDE APPLICATION. THIS SENSOR (TIDGET), WAS DEVELOPED WITH IN-HOUSE FUNDS FOR LOW-COST TRACKING APPLICATIONS AND CAN BE PACKAGED IN THE CURRENT MSS RADIOSONDE HOUSING. WITH THE TIDGET, THE GPS C/A CODE-PHASE IS MEASURED AND RELAYED TO THE MSS TO COMPUTE POSITION USING DATA FROM A GPS REFERENCE RECEIVER. OTHER DATA, THAT IS, PRESSURE, TEMPERATURE, HUMIDITY, AND WINDS WOULD BE PROCESSED IN THE NORMAL MANNER. UPPER ATMOSPHERIC OBSERVATIONS ARE REQUIRED WORLDWIDE IN SUPPORT OF TOTAL DOD REQUIREMENTS. CURRENTLY, THERE IS NO SYSTEM THAT WILL SUPPORT THE REQUIREMENTS OF GLOBAL COVERAGE, SILENT OPERATIONAL REQUIREMENTS, PRECISION, AND SIMPLICITY OF GROUND STATION EQUIPMENT. A GPS OPERATIONAL RAWINSONDE SYSTEM WOULD SATISFY TOTAL DOD REQUIREMENTS FROM MISSILE RANGE OPERATIONS TO BATTLEFIELD DEPLOYMENT. SUCH A SYSTEM WOULD ALSO SATISFY THE NATIONAL WEATHER SERVICE REQUIREMENTS FOR A COMPACT AUTOMATED SYSTEM TO SUPPORT THEIR OPERATIONS AT 100 UPPER AIR STATIONS. TOTAL U.S. RADIOSONDE REQUIREMENTS IS OVER 100,000 ANNUALLY. THIS QUANTITY SUPPORTS THE DEVELOPMENT OF A RELATIVELY LOW-COST GPS-TYPE RAWINSONDE SYSTEM.