Performance of a Tightly Coupled GPS/Inertial System using a FOG-based IMU

This paper describes the design and results of a tightly coupled GPS/inertial system. Real flight data is used to demonstrate the performance of the integrated GPS/inertial system. The performance analyses consider the Appendix R of Radio Technical Commission for Aeronautics (RTCA) document DO-229D. Appendix R provides the requirements and test procedures for tightly integrated GPS/inertial systems. Compliance with Appendix R ensures a comparability of the system performance and offers a consistent basis for certification for these types of systems. The presented system uses a mid-range IMU with fiber optical gyros (FOG) and an aviation L1 GPS receiver. The integration algorithm is based on a closed-loop error state Kalman filter. The optimal complexity of error state modeling and number of error states for the given hardware will be identified. Solution separation will be combined with an extrapolation method for integrity, fault detection, and exclusion algorithm.