EVALUATION OF TWO COMPUTATIONAL TECHNIQUES OF CALCULATING MULTIPATH USING GLOBAL POSITIONING SYSTEM CARRIER PHASE MEASUREMENTS

Two computational techniques are used to calculate differential phase errors on Global Positioning System (GPS) carrier war phase measurements due to certain multipath-producing objects. The two computational techniques are a rigorous computational electromagnetic technique called Geometric Theory of Diffraction (GTD) and the other half is a simple ray tracing method. The results from the two techniques are compared to GPS differential carrier phase taken on the ground using a GPS receiver in the presence of typical International Space Station (ISS) interference structures. The calculations produced using the GTD code compared to the measured results better than the ray tracing technique.