Abstract:

In order to overcome the dependence of detection performance of the traditional snapshot algorithm on large pseudo-range bias, a multiple epochs solution separation RAIM algorithm considering alarm time is proposed. In this algorithm, the test statistics of the solution separation RAIM in multiple epochs are accumulated to improve the detection ability on small and slowly growing biases under the hypothesis of the independence of observation noise between epochs. The superior performance of the proposed algorithm is verified via simulation by using step and ramp faults, where the comparisons to solution separation RAIM and multiple epochs least squares residual RAIM algorithms are designed. The results show that the proposed algorithm can significantly reduce the minimum detection bias of the step fault and the minimum detection slope of the ramp fault within alarm time, and shorten the detection time-delay of the ramp fault apparently when alarm time exceeds the threshold.

Key words: receiver autonomous integrity monitoring (RAIM), time to alarm (TTA), multiple epochs, solution separation, small and slowly growing pseudo-range bias