Study Of Auto-Compensation Technique Based On Rotation Of IMU For SINS

Inertial measuring units are directly fixed and bonded to carriers in strapdown inertial navigation system, which can omit frame structure, electrical stable system, contacting sliding ring and so on. This kind of system with the advantages of small size, light weight and high degree of reliability may replace platform inertial navigation system gradually.With the influence from precision of inertial measuring unit and working condition, the precision of strapdown inertial navigation system is lower than that of platform inertial navigation system. Compared to high costs of improving components' precisions, auto-compensation technique has lower costs, less difficulties and obvious effects, which observe the errors of inertial measuring unit in system. According to the characters and rules of errors, this method can limit and decrease the influence of errors in the system effectively and improve the precision of navigation system.Auto-compensation technique is a method of automatic correction. It does not introduce external correction information, but it can measure and compensate the errors of system inertial measuring units, and counteract the influence of errors to system precision automatically.In the purpose of improving the precision of strapdown inertial navigation system, techniques of improving navigation system's precision was analyzed firstly. Then the basic and algorithm equations were derived, and the system simulation programs were implemented respectively. Through the analysis for the error models of strap down inertial system, the influences of gyroscope drift and accelerometer zero-bias to parameters of navigation system were studied. With the reference of the auto-compensation technique of platform inertial navigation system, a auto-compensation plan on strapdown inertial system has been proposed, which can automatic compensate error by the rotation of inertial measuring components. The rotation on error inhibition effects of inertial measuring components were studied, the inhibition principles of rotation to different error sources were analyzed, error inhibition effects of different rotation plan were studied and the inhibition results of every plan have been compared comprehensively as well. At last the verification experiments have been designed, which can test the inhibition effects of navigation parameters errors under different rotation plans and verify the rotation plans in projects.Through the theoretical analysis, system simulation and engineering experiments in the paper, the auto-compensate technique based on rotation of inertial measuring units has been proved to be an effective method to improve the precision of strapdown inertial navigation system.