Performance and Stability Analysis of INS/GPS Ultra-tight Integration with INS Aided Receiver Tracking Loops

Li Fu and Yu Chen

Abstract:	To satisfy the increasingly challenging specifications in terms of accuracy and availability of the positioning and velocity solution, especially in scenarios where reliable and robust navigation is needed but radio signal detection is hindered by obstacles or the aircraft is suffering high dynamics, a novel INS aiding Doppler estimator based on the Extend Kalman Filter (EKF) was present. The use of inertial sensor would improve the tracking performance since the Doppler frequency caused by aircraft dynamics could be compensated by the inertial measurements. Via the concept of Integral Quadratic Constraints (IQC) theory, the absolute stability conditions of the GPS tracking loops aided by INS Doppler information are derived in a nonlinear framework, thus providing the reference of reliable and robust navigation system for practical engineering application. Meanwhile, by regulating the error estimations from the Extend Kalman Filter (EKF) method, the carrier frequency is carefully tuned to acquire optimal tracking ability. In order to evaluate the proposed system, a GPS tracking loop aided by MEMS INS is developed by using a software receiver, and a four-stage high dynamic flight test is also conducted by the INS signal simulator. The signal power distribution of In-phase and Quad-phase for the tracking result is given in each high dynamic stage. The simulation test shows great coincidence with the theory analysis and Doppler aiding increase the receiver’s robustness to interference and jamming. Compared to the conventional loose or tight integration, the accuracy of the ultra-tight INS/GPS integration with aided tracking loops is improved under attenuated signal environments. The result also shows these methods proposed in this paper to achieve the stability conditions of the closed loops are of great availability.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2406 - 2416
Cite this article:	Fu, Li, Chen, Yu, "Performance and Stability Analysis of INS/GPS Ultra-tight Integration with INS Aided Receiver Tracking Loops," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 2406-2416.
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