Abstract: A MEMS-IMUs based dual SINS/GPS/Doppler integrated navigation system is designed, and this will make the integrated system to have a systemic redundancy. The construction of the integrated system, the designing and calculation of the hierarchic alliance Kalman filter are discussed in this paper. Then the hard failure FDIR algorithm based on the filter measurements residuals and the soft failure FDIR algorithm based on the state esimations are given. The result of simulation shows that this system is better as flexible structure.