Inertial Navigation System Aided by GPS and Selective Frequency Contents of Vector Measurements

This paper proposes an aiding technique to enhance error estimation in low-cost strapdown inertial navigation systems with application to Unmanned Air Vehicles (UAVs). The paper summarizes a high-accuracy, multi-rate integrated Global Positioning System/Inertial Navigation System (GPS/INS) using Extended Kalman Filter (EKF) for error compensation. A proposed new technique decomposes and optimally integrates the magnetic and gravitational observations in the EKF, taking into account the vehicle’s dynamics bandwidth information to properly trace inertial motion. In particular, the paper evidences that inertial misalignment errors and biases can be effectively estimated resorting to the gravity vector low frequency information embodied in accelerometer measurements. The performance of the overall INS aiding architecture is assessed in simulation, and results obtained about UAV typical trajectories are presented and discussed.