GPS-INS Integration for Autonomous Navigation of Aircrafts

The advent of Global Navigation Satellite Systems has brought about an additional navigational aid for aircrafts. Due to their complementary error characteristic, various approaches involving Global Positioning System coupled with the Inertial Navigation System have been looked into for complete autonomous navigation and attitude estimation of the aircraft. In this paper, we study, through simulation, approaches of GPS-INS integration based on the extended Kalman filter. An open-loop tightly-coupled GPS-INS integration approach utilizing raw pseudorange measurements is analyzed in presence of realistic measurement errors. Improvements in the approach, via bias estimation and carrier phase tracking have also been briefly examined. Lastly, a computationally efficient approach to resolve integer ambiguities for carrier phase tracking is also simulated. Although the results presented are based on GPS simulation, the analysis is equally applicable to other satellite navigation systems due to their similar operating principles. Keywords—Extended Kalman Filter, GPS-INS integration