Using multi-frequency for GPS positioning and receiver autonomous integrity monitoring

Algorithms using multi-frequency for GPS positioning and receiver autonomous integrity monitoring (RAIM) are proposed by the authors. In the conventional algorithms, only single frequency L1 is applied. After the L2 and L5 signals are applied, the ionospheric delay can be removed. Therefore, the variance of the measurement error is reduced, the positioning accuracy is improved, and the detection time of satellite failure is decreased. In addition, a cleaner parity vector is obtained, so the incorrect exclusion rate (IER) is significantly reduced. This paper provides a systematic way to derive the algorithms of the positioning and RAIM for multi-frequency GPS receiver. Simulation results show that, in comparison with the conventional single frequency method, the proposed multi-frequency algorithms not only possess more accurate positioning results, but also demonstrate higher performance in detecting small failures and, in detecting large failures, demonstrate a similar level of performance. Moreover, simulation results also verify that the proposed method has lower IER than the conventional single frequency method.