This paper evaluates the use of a Kalman filter for improving RAIM. Estimates of satellite clock offsets become the test statistics. It is found that, for a snapshot algorithm, there is no difference between conventional, parity space RAIM and that based on the Kalman filter. When time histories are used and the satellite offsets are modeled as ramps, it is found that there is improvement when the slope of the ramp offset is greater than about 6m/sec. If a crude intertial navigation system were included, it is possilbe to have significant improvement when fault producing ramps take as long a 3 mimutes to develop.
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