Abstract: SINS/GPS/Landmark integrated navigation system was proposed according to the flight characteristic of the stratospheric airship.The observation equation of SINS /Landmark integrated navigation system was deduced and the improved SageHusa adaptive filtering method combined with federated filter was applied to SINS/GPS/Landmark integrated navigation system.Simulation results show that this new integrated navigation system can improve the attitude precision effectively relative to SINS/GPS integrated system and the improved adaptive federated filter can enhance the global estimation accuracy.