Status of marine high-precision GPS navigation system

Western Geophysical has been developing a proprietary high-precision differential GPS (Global Positioning System) marine navigation system with the goal of providing submeter real-time positioning of a marine seismic survey vessel located up to 1000 km from a land-based reference station. The system measures L1 and L2 group delay observables without knowledge of the P code and uses them to derive the ionospheric corrections. Various land-based tests have been run on a prototype system, demonstrating the capability of obtaining real-time accuracies of 1 m and post-fit submeter absolute accuracies at distances up to 650 km, with average errors consistently less than 0.5 m. Results of the tests are reported.< >