According to the gyroscope, the inertial navigation system can be divided into electromechanical (including liquid floating, air floating, static electricity, flexible, etc.) gyroscopes, optical (including laser, optical fiber, etc.) gyroscopes, micro mechanical (MEMS) gyroscopes Other types of inertial navigation systems.
According to the mechanical arrangement of the inertial navigation system, it can be divided into: platform inertial navigation system and strapdown inertial navigation system.
The platform type inertial navigation system is an inertial navigation system that fixes inertial components such as gyroscopes and accelerations through a gimbal angular motion isolation system and a moving load. The inertial measurement device (accelerometer and gyroscope) is installed on the electromechanical navigation platform, and the carrier motion parameters are measured based on the platform coordinate system. The platform type inertial navigation system isolates the angular motion of the carrier by the frame servo system, so that high system accuracy can be obtained.
The strapdown inertial navigation system, its inertial measurement device (accelerometer and gyroscope) is directly mounted on the carrier of the aircraft, ship, missile, etc. When the carrier rotates, the sensitive axis of the accelerometer and the gyroscope also follow the rotation. The gyroscope measures the angular motion of the carrier and calculates the attitude angle of the carrier to determine the accelerometer's sensitive axis pointing. Then, through coordinate transformation, the signal output by the accelerometer is transformed into a navigation coordinate system to perform navigation calculation.
At present, the platform inertial navigation system has reached a very high level, but its cost and maintenance cost are very expensive, and its frame servo system is adopted, and the relative reliability will be degraded. Strapdown inertial navigation technology was developed in the 1960s. The inertial measurement device is mounted directly on the carrier instead of the electromechanical platform. The mathematical platform replaces the navigation technology of the electromechanical navigation platform. The strapdown system is easy to measure and mount. Installation, repair and replacement, small size, is an important development direction of inertial navigation technology. However, the strapdown system directly fixes the inertial measurement device on the carrier, which deteriorates the working environment of the inertial measurement device and reduces the application accuracy of the system.
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