Precise navigation & positioning is a key issue for ship navigation.The principles of strapdown inertial navigation system(SINS),celestial navigation system(CNS),and Doppler navigation system(DNS) are given,and the state equation and measurement equation of information fusion are given in detail.Data including the position and attitude information provided by the CNS,and ship velocity information acquired by Doppler velocity sonar,are integrated with the SINS to improve the accuracy and reliability of ship navigation.Simulation experiment is carried out for the integrated navigation system,and the simulation results show that the fuzzy adaptive Kalman filter has high convergence speed and certain fault tolerance,which can improve the accuracy of the integrated ship navigation system.