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The conventional receiver autonomous integrity monitoring (RAIM) algorithm of pseudo-range residualcauses large residual error without a relatively accurate priori receiver position,which may lead to fault detection and identification.Therefore,measurements with gross errors may be used in positioning instead of high quality ones,especially when there are more than one measurement being distorted by gross errors.Meanwhile,the accuracy of the positioning result will be seriously deteriorated.In order to solve this problem,a new robust RAIM algorithm with positioning result based on the proportion of visible satellites is proposed in this paper.Usingtheproportion of visible satellites,the new algorithm produces a coarse position by the least squares method to calculate the pseudo-range residual.Accordingly,a robust approach to evaluate the accuracy of the coarse position based on the least median square (LMedS) is also proposed to make sure the position can meet the requirements of the following fault detection.In addition,the threshold mentioned in the new algorithm is derived theoretically.Finally,the performance of the new algorithm is good in simulations and real-data-tests,compared with conventional approaches.Results show that under the complicated scenarios the newalgorithm can provide aconsiderablereduction of the probability of missdetection (7.89% in this test),and improve the positioningaccuracy remarkably.