INS-aiding information error modeling in GNSS/INS ultra-tight integration

In the ultra-tight integration system of the global navigation satellite system/ inertial navigation system (GNSS/INS), the error models of INS aiding information are significant to analyze the performance of system. However, it is difficult to comprehensively describe the error propagation process between INS and GNSS when using the traditional transfer functions and inertial computation formulas. To overcome the issues, a comprehensive error modeling scheme of INS aiding information for GNSS tracking loops is proposed from the state space design perspective. Using the proper integrated navigation filter derived in Earth-centered, Earth-fixed frame, the error propagation process from integrated navigation filter to INS-aiding information can be constructed, by taking the overall error sources into consideration. In addition, the error item of acceleration caused by rotations of the line-of-sight direction is analyzed, which is especially important for high-dynamic receivers or middle-orbit satellites positioning. Simulation and experiment results verify the effectiveness of the proposed error modeling method. This method has significant application potential for the performance analysis of tracking loops in GNSS/INS ultra-tight integration system.