Inertial navigation system is a kind of inferred navigation method. That is, the position of the next point is derived from the position of a known point based on the continuously measured heading angle and velocity of the carrier. Therefore, the current position of the moving body can be continuously measured. The gyroscope in the inertial navigation system is used to form a navigation coordinate system to stabilize the measurement axis of the accelerometer in the coordinate system and give the heading and attitude angles; the accelerometer is used to measure the acceleration of the moving body and obtain an integral of the time. Speed, speed and then an integral of time to get the distance. The inertial navigation system has the following main advantages. (1) Since it is not dependent on any external information. An autonomous system that does not radiate energy to the outside. Therefore, it is concealed and is not affected by external electromagnetic interference; (2) It can work on the surface of the earth and even underwater under the global and full time. (3) It can provide position, speed, heading and attitude angle data, and the generated navigation information has good continuity and low noise. (4) High data update rate, short-term accuracy and stability. The disadvantages are: (1) because the navigation information is generated by integration, the positioning error increases with time, and the long-term accuracy is poor; (2) a longer initial alignment time is required before each use; (3) the price of the device is relatively high. Expensive; (4) can not give time information.