The necessity and possibility of the integration of DNS and the approach to the integration are expounded. The error model and the Kalman filtering model are given. There are three kinds of integration modes according to different measurements. By simulated calculation

the corresponding curves are given. When adopting the pseudorange and its rate as observed variables

the integration mode is the best. The position accuracy can attain the order of meter on each axis

and the heading accuracy can be raised to 0. 2°.