GPS error modeling and OTF ambiguity resolution for high-accuracy GPS/INS integrated system

The Center for Mapping at The Ohio State University is currently developing a fully digital Airborne Integrated Mapping System (AIMS) for large-scale mapping and other precise positioning applications. AIMS, installed in an aerial platform, incorporates state-of-the-art positioning [differential Global Positioning System (GPS) integrated with an Inertial Navigation System (INS)] and imaging (Charge-Coupled Device) technologies. The project goal is to develop a low-cost hardware prototype that acquires position and orientation of an aerial platform with accuracy of 4-7 cm and below 10 arcsec, respectively, over long baselines, and performs essential processing of digital imagery in real-time and in post-processing mode. A tightly integrated GPS and high-accuracy INS provide orientation and position of the aerial platform. To the best of the authors' knowledge, AIMS is the first tightly integrated GPS/INS system whose existing prototype promises sub-decimeter accuracy in positioning, and below 10 arcsec in orientation, in the airborne scenario. However, the expected high performance still remains to be verified against the ground truth. The new GPS/INS tightly integrated system for high-precision airborne applications is described, with special emphasis on the GPS component of the system. The evaluation of the actual prototype and the airborne test results are discussed. A detailed description of the tight GPS/INS integration and Kalman filter implementation is presented elsewhere.