Multi-constellation RAIM for approach with vertical guidance

Receiver autonomous integrity monitoring(RAIM) can be used for approach with vertical guidance(APV) in anticipation of multi-constellation and multi-frequency signals in future global navigation satellite systems(GNSS).This study analyzes a multi-constellation RAIM algorithm with simultaneous two-satellite faults.All satellites in view are divided into three groups and the final positioning solution is the weighted average of the three solutions calculated by each group separately.An optimal weight ratio is found iteratively,to maximize the algorithm availability while taking into account the accuracy requirements.Simulations show that this algorithm can be used for APV-I with an availability of 100% and can be used for APV-II with an availability of more than 99%.