Research On GNSS Receiver Autonomous Integrity Monitoring Algorithm

Global Navigation Satellite System(GNSS) plays an important role in today's society. It can work continuously throughout the day, and provide highly accurate positioning, velocity and time information. GNSS has been widely used, both in the military, and in civilian terms. As the high-level users of satellite navigation, the civil aviation field makes strict demands on the integrity of GNSS positioning.In this paper, it studys on the improvement of GNSS integrity and achieves good results.By analyzing the GNSS positioning principle and Receiver Autonomous Integrity Monitoring(RAIM) theory, the principle of the traditional algorithm RAIM algorithms for satellite fault detection and isolation can be obtained. As the actual for noise is nonlinear and non-Gaussian, so the particle filter algorithm is used in interity monitoring. By analyzing the standard particle filter(PF) algorithm, it has the disadvantage of the loss of particles diversity. For this problem, the particle swarm optimization(PSO) algorithm is to optimize the particle filter in sampling process, which can increase the effective number of particles and achieve better system state estimation results.The PSO-PF algorithm, combined with RAIM algorithm, is used in satellite fault detection and isolation. With the actual navifation data, and adding different values bias of step step pseudorange and different slope of gradual deviations, it can validate the PSO-PF-RAIM algorithm by comparing with the PF-RAIM algorithm. Results show that the PSO-PF-RAIM algorithm can improve the satellite fault detection rate, shorten the time of alarm, and can quickly identify the number of failed satellite. It means that the PSO-PF-RAIM algorithm is effective ad feasible.Finally, considering the realization of the PSO-PF-RAIM algorithm, then the PSO-PF-RAIM algorithm is implemented on FPGA. According to the FPGA block diagram of the algorithm, each module of PSO-PF-RAIM algorithm is simulated, and then it reaches the design requirements for satellite fault detection and fault identification.