Research On Inertial-assisted GNSS Tracking Loop And Integrity Monitoring Technique

With the continuous development of global satellite navigation system,the system performance and requirements gradually increased.But under weak signal,the GNSS receiver cannot track the GNSS signal,and will cause a large positioning error.Also single satellite navigation system cannot catch the slope error and it will costs a long alarm time.To solve these problems,GNSS receiver tracking loop and GNSS integrity monitoring technique were studied in this paper based on the National Natural Science Foundation of China(NSFC)project "Research on Signal Processing Method of GPS / MIMU Deep Combination Tracking Loop Based on MEMS",and GPS is taken as an example.Firstly,the traditional GPS receiver tracking loop and the improved EKF-based receiver tracking loop were deeply analyzed.Secondly,an inertial-assisted EKF tracking loop was proposed to solve the tracking problem under weak signal.The model of the inertial-assisted EKF tracking loop was analyzed and simulated contrasted with the traditional loop.Thirdly,the GNSS integrity monitoring technique based on least squares residual method was deeply analyzed.And a total least squares residual method and a multi-star fault recognition method were proposed based on the traditional algorithm.Finally,to solve the problem of slope faults cannot be identified for the single satellite integrity monitoring algorithm,an algorithm for inertial-assisted rate monitoring is proposed.The simulation results show that the algorithm can detect not only the satellite slope fault but also the INS slope fault,and it can effectively shorten the integrity monitoring alarm time.