Abstract: The generalized likelihood test method is studied, and the result shows that it is unable to identify the simultaneous multi-faulty satellites. In order to identify multi-faulty satellites rapidly, and to improve the reliability of satellites navigation system, a new receiver autonomous integrity monitoring(RAIM) algorithm is proposed, which is called assuming and validating method. This method validates every possible faulty satellites combination, computes satellite pseudorange deviation for each combination, and then constructes a new parity residual vector by the deviation, finally provides the judging result with the judging function. Computer simulation is achieved under the conditions of simultaneous twofaulty satellites and simultaneous threefaulty satellites, and the results indicate that compared with the other existing methods of the same kind, the assuming and validating method increases correct identifying ratio which will be higher than 85%. This method will improve the reliability of satellites navigation system. Moreover, compared with the optimal parity vector method, this method avoids computing the generalized eigenvectors of matrix, and its computation load decreasesmore than 90%.

Key words: satellite navigation, RAIM, generalized likelihood test, fault identification, assuming and validating method