DME/DME/SINS integrated navigation system is the primary navigation method for RNAV. A robust DME/DME/SINS integrated navigation algorithm is proposed. First, the state equation of KF is established based on the error propagation equation of SINS; Then the measurement equation of KF is established by deriving the relationship between the slant-range error and the state variables; Finally, aiming at the problem that the outliers in the slant-range given by DME degrade the navigation accuracy, a robust huber-based KF is utilized to achieve the information fusion. The experiment results indicate that the proposed integrated navigation algorithm can meet the requirement of RNAV-1; Meanwhile, the algorithm is robust to the measurement outliers since the Huber-based KF is used.