Abstract: The method of SINS alignment with distance-transfer-unit aiding is studied. The SINS/DTU system's observable matrices in different moving bases are obtained by using the method of analyzing the piece-wise constant system. The observabilities of SINS/DTU integration system are analyzed according to the singular-values of the observable matrices. SINS/DTU integration system and SINS/GPS integration system are compared. The simulation results are given. The results indicate that SINS autonomous alignment can be completed by SINS/DTU integration. But the obsevabilities of SINS/DTU integration are slightly less than that of SINS/GPS integration, and the former needs a longer time than the latter in moving base alignment.