Research On GNSS Receiver Autonomous Integrity Monitoring Technology

Recent years, along with the application and development of the GNSS system in various fields all over the world, the technology of GNSS navigation and position has made big success. The GNSS system has satisfied the required precision of the majority of the users. However, for some of the life safety involved public transportation industry, especially the civil aviation industry, the integrity of the system is of much more importance and research significance than accuracy only. Therefore, taking into the integrity requirement of the users under different conditions, this work investigats the receiver autonomous integrity monitoring technology, and includes several parts that listed as follows:Firstly, the research background and current development of RAIM technology are introduced. Based on the observation model, the least square residual RAIM and parity vector RAIM are deduced. Moreover, the paper proves the equivalence of the two methods through theoretical demonstration.Secondly, the problem of tiny graded fault for high precision users is investigated based on the basis of the parity vector algorithm, and a modified method is proposed to improve the detection of these faults by using new accumulated statistic that integrates the residuals and temporal information. Then this method is combined with the traditional RAIM to overcome its insensitivity for abrupt faults. The simulation results prove that the new method has achieved better detection effect. Also, a fault detection algorithm that combines fault characteristics plane and the parity vector is explored to improve the double-fault identification performance.Then, the problem of BDS/GPS/GLONASS integrated navigation system is researched under the background of GNSS system, and a random search RAIM algorithm that is compatible with both single fault and multiple faults has been investigated on this basis. And a revised algorithm was proposed to improve the identification performance by using satellite random-selection method and threshold optimization method. The simulation show that the modified method can have better performance without large increase in calculation.Finally, the reason of the conservation of RAIM availability algorithm is researched, and the MHSS algorithm that can directly calculate VPL to satisfy integrity risk is used. Then a technique that dynamically allocates the risk of integrity and continuity is proposed to improve RAIM availability. Moreover, the simultaneous method and time-share method are deduced respectively, and the simulation experiment is executed to prove its advancement.