Research On New Algorithms And Applications Of Receiver Autonomous Integrity Monitoring

Receiver automous integrity montoring (RAIM) is an impormant approach for guaranteeing integrity of aviation users. In this paper, we mainly denote to the study of new RAIM algorithms and their applications. Firstly, in order to solve the problem of multiple faults detection and identification in satellite navigation systems, we propose two algorithms, Bayesian methods and methods based on independent component analysis (ICA), for handling multiple faults. Secondly, a new advanced RAIM (ARAIM) algorithm is designed, and then it is used to analyze the availability of the worldwide LPV-200 guidance of the civil aircraft. Thirdly, for the purpose of serveing special users, a new clock-aided ARAIM algorithm based on single satellite navigation system is given, and then it is used to analyze the availability of the worldwide LPV-250 guidance. Fourthly, a new carrier-phase RAIM (CRAIM) algorithm is designed using vector auto regression (VAR) model, and the effectiveness of this algorithm in the application of shipboard relative GPS (SRGPS) integrity montoring is examined. The main innovative points and research achevements of this paper are as follows.1. Two new algorithms for handling multiple satellite faults are designed. First of all, a method for multiple faults detection and exclusion is proposed based on the independent component analysis (ICA) of GNSS time series and is validated by the data from 5 iGMAS monitoring stations in China. Secondly, a new Bayesian approach for multiple satellite faults detection and exclusion is proposed based on classification variables. Introducing a classification variable to each satellite observation, the testing criteria for satellite faults detection and exclusion based on the posterior probabilities of the classification variables are given in the respective of Bayesian hypothesis test. Several experiments are designed to evaluate the effectiveness of the proposed Bayesian RAIM algorithm in the case of multiple faults under the dual constellations of simulated GPS and BDS. Real observations of the CHAN station in IGS are also analyzed by this algorithm.2. A new ARAIM algorithm under multiple constellations is proposed and the availability of it for the guidance of worldwide LPV-200 is examined. Firstly, a new algorithm for multiple faults detection and exclusion is proposed based on the prediction errors of the observations time series of each satellite in the temporal direction which are modeled by an autoregressive moving average (ARMA). Secondly, a method for computing the exact probabilities of missed detection is designed so that a quantitative analysis method is proposed for the evaluation of the faults detection and identification algorithm. Thirdly, a new allocation method for integrity risk of ARAIM is designed, and then the formulas for computing the corresponding protection levels are given. Fourthly, some examples are designed based on the MAAST software of Standford University to evaluate the effectiveness of the faults detection and identification algorithms and to examine the availability of the worldwide LPV-200 guidance.3. A new clock-aided ARAIM algorithm based on single satellite navigation system is given, and then it is used to analyze the availability of the worldwide LPV-250 guidance. Firstly, the predictions of clock offsets that are considered as virtual pseudo-ranges are taken into the positioning under the single constellation. Secondly, the responsibility of satellite faults montoring is undertaken by the Bayesian methods, and then we can alarm users when satellite faults are found. Thirdly, after allocating the integrity risks, the formulas of protection level are given. Then we illustrate some examples to examine the availability of the worldwide LPV-250 guidance under the simulated BDS and the randomly seclected 14 IGS satations.4. A new CRAIM algorithm is designed in RTK positioning using VAR model. Firstly, considering the correlations of the observations under the positioning algorithms based on carrier phases, we fit the double differenced carrier phase observations with VAR model so as to handle the multiple satellite faults. Secondly, according to the accurate calculation of missed detection, a quantitative analysis method is designed for the reliability of the faults detection and identification algorithm. Thirdly, a new allocation method for integrity risk of CRAIM is designed. Then starting from the integrity risk, an algorithm for computing protection levels is given. If the postioning solution of the current epoch is abnormal, we alarm users.5. We apply the new CRAIM algorithm above to the integrity montoring of SRGPS system. Firstly, we handle the faults in the double differenced carrier phase observations using the algorithms above by means of VAR model. Secondly, ambiguity resolution is implemented by the LAMBDA method and the success rate is used to montor the integrity of ambiguity. Thirdly, combined the navigation algorithms of SRGPS with the integrity montoring algorithms designed by this section, we give the whole flow chart of the integrity montoring for SRGPS terminal navigation. Finally, we simulate the process of the SRGPS terminal navigation under the simulated BDS in Nanhai of China by maens of Satellite Toolkit (STK). This experiment is implemented besed on the simulated BDS, which makes a preliminary exploration for the establishment of SRBDS in China.