Abstract: With more satellites in view, the probability of simultaneous multiple satellites failure increases. The traditional Receiver Autonomous Integrity Monitoring（RAIM） method is usually adopted to detect and exclude one faulty satellite; however, it cannot work in such a multiple satellites failure environment effectively. Based on the parity check, a modified RAIM method for identifying two-faulty satellites is proposed. The modified RAIM finds the satellites without error on pseudo-range and computes the position of GPS receiver with the information of these satellites. And then it calculates the pseudo-range error to identify and exclude the faulty satellites. The simulation results prove that the modified RAIM method is able to solve the failure counteraction caused by the parity vector method.

Key words: Receiver Autonomous Integrity Monitoring（RAIM）, double satellites failure, failure counteraction, parity vector, identification of satellites without failure

摘要： 当接收机可以观测到的卫星数目增加时，多颗卫星同时出错的概率大大增加。传统的接收机自主完善性监测算法（Receiver Autonomous Integrity Monitoring，RAIM）通常用来检测并识别一颗故障卫星，在多颗卫星同时出错时的识别结果并不理想。提出了一种改进的RAIM算法，在奇偶矢量法的基础上，从找出无故障卫星出发，进一步用这些无故障卫星信息进行粗略定位，由接收机的粗略位置来计算各颗卫星的伪距偏差，从而识别出并剔除故障卫星。经仿真验证，该方法可以解决两颗故障卫星时奇偶矢量法中的故障偏差抵消问题。

关键词: 接收机自主完好性监测, 双星故障, 故障偏差抵消, 奇偶矢量法, 识别无故障卫星