The Research On Receiver Autonomous Integrity Monitoring Of GNSS

Along with the technology upgrading modernization plan of GPS and GLONASS, the integrated development and implementation of GALILEO and the COMPASS, the positioning precision of GNSS had been greatly improved, but either the navigation system or their integrity augmentation system has not met the actual requirements of system and dynamic users. With a view to the users’safety, for a navigation system or the integrity of the navigation system, the integrity has a far more important status.However, at the moment, for the GNSS, the integrity monitoring of GNSS is still on its initial stage, neither system structured nor the algorithm analysis are developed into unified mode. The integrity facilities and technology cannot meet the requirements of practical application. So in order to analyze and investigate the correlative theory, method, core algorithm and key technology of GNSS integrity monitoring, especially RAIM which is widely-used, the principle and correlative technologies of integrity monitoring were deeply studied, the RAIM algorithm and model are founded, and the validation and effectiveness are also proved through experiment and simulation.The main work in this paper is as follows:(1) An integrity algorithm which applies rapid ephemeris is designed to complete the satellite SIS monitor at the receiver. Experiment shows that the method can detect and exclude satellite fault correctly and ensure the GNSS performance of navigation and integrity.(2) The traditional w algorithm cannot detect more than one satellite faults which appeared along with the increase of satellite numbers correctly, this paper present a improved W algorithm which could exclude multiple faults correctly while ensuring the positioning precision.(3) In order to solve the unreasonable situation that the integrity risk is average allocated in the existing RAIM algorithm, a scheme is designed in which integrity risk is dynamic allocated。Experiment shows that the improved RAIM could reduce value of the protection level effectively and improve the availability of the GNSS.