Research On RAIM Algorithm Aided By Satellite Navigation Signal

With the rapid development of satellite navigation,the requirements for the integrity performance of satellite navigation systems have also increased.In order to realize the receiver autonomous integrity monitoring at the signal level,and not limited to pseudo-range redundant observation,this thesis conducts in-depth research on receiver autonomous integrity monitoring(RAIM)technology.The specific research contents are as follows:(1)The structure of the satellite navigation signal and the principle of acquisition and tracking are analyzed.The relevant parameters are obtained during the signal acquisition and tracking process.The principle and operation process of the fault detection and recognition algorithm are described in detail.A common RAIM algorithm is studied and its fault detection results are obtained through experimental simulation.(2)Aiming at the problem that the existing RAIM algorithm is based on pseudo-range redundancy,and not considering the impact of the satellite navigation signal itself on the algorithm,a RAIM algorithm based on satellite navigation signals is proposed.The RAIM algorithm based on satellite navigation signal is proposed.By introducing the parameters acquired by the satellite navigation signal in the process of capture and tracking,the new covariance matrix and test statistic are constructed,and fault detection is realized.Experiments show that this method can improve the sensitivity of fault detection.(3)Based on the algorithm of content(2),an improved RAIM algorithm based on satellite navigation signals is proposed.By introducing the RAIM algorithm based on the weighted least squares residual,the noise power values of the two algorithms are combined,and a criterion is established to make the noise power mean equal to construct a new covariance matrix.Then,new test statistics are obtained and fault detection is implemented.Experiments show that the sensitivity of fault detection is improved compared with the RAIM algorithm based on weighted least squares residual and the RAIM algorithm based on satellite navigation signals.(4)The contents (2) and (3) use satellite signals to achieve fault detection.The selection of satellites also becomes an important condition for ensuring the performance of integrity monitoring.Therefore,for the problem of instability of the satellite selection result of particle swarm optimization(PSO),the key parameters of PSO satellite selection algorithm including inertia weighting factor,acceleration coefficient and population size are considered to affect the performance of PSO satellite selection algorithm.The adaptive inertia weight and simulated annealing algorithm are proposed to improve the PSO satellite selection process,and the adaptive simulated annealing particle swarm optimization(ASAPSO)satellite selection algorithm is obtained.Experiments show that the performance of this algorithm is better than that of PSO satellite selection algorithm,which guarantees the performance of integrity monitoring.