Differential Solutions Using Long-Range, Dual- Frequency GPS Correction Data

Military applications of space-based navigation systems have led to important enhancements to our fighting capability and are being applied to many phases of operations. The Global Positioning System (GPS) is a key factor for making this a reality. GPS provides accurate position, velocity and time information. Stand-alone GPS receivers may not provide the requisite accuracy to fulfill mission requirements. This thesis focused on the accuracy and relevance of applying dual-frequency GPS correction data to compute differential GPS (DGPS) solutions. Analysis was performed to assess the viability of using correction data from reference receivers at extended ranges, 2000-3000 km away, to perform after-the-fact positioning by analyzing stand-alone GPS accuracy versus dual-frequency corrected techniques. This could be extended to real-time operations. The differentially-corrected technique produced more accurate results than stand-alone GPS at all ranges. The stand-alone GPS horizontal root mean square (RMS) accuracy was 5.9 meters while the differentially-corrected RMS accuracy was under 1.5 meters to 2000 kilometers and under 3.0 meters to 3200 kilometers. The process has applicability in determining GPS solutions for long-range military uses. It is possible to use U.S. or Allied GPS assets at long distances from areas of operations to prosecute targets of high interest.