Initial alignment method for MEMS-IMU

Abstract

The invention discloses an initial alignment method for an MEMS-IMU. Through the initial alignment method, the initial rough alignment time of a strapdown inertial system is further shortened, and the precision of the strapdown inertial system is further improved. The initial alignment method comprises the following steps that 1, sensor data are acquired, wherein the sensor data comprise the data of an MEMS gyroscope and an MEMS accelerometer; 2, initial alignment coordinate systems are established, wherein the initial alignment coordinate systems comprise the solidified carrier coordinate system, the earth coordinate system, the navigation coordinate system and the carrier coordinate system; 3, initial alignment objective functions are established, and an optimal speed reducing method of quick alignment is constructed; 4, a parameter equation of the optimal speed reducing method is determined through the complementary filter principle; 5, a carrier attitude angle is resolved through an quaternion updating algorithm, and calculation of an initial attitude matrix is achieved. According to the initial alignment method for the MEMS-IMU, the calculation precision and efficiency of an initial alignment algorithm are effectively improved, and the application range is wide.

Description

technical field [0001] The invention relates to an initial alignment method of a MEMS-IMU under shaking base and vibration conditions, and belongs to the technical field of strapdown inertial navigation. Background technique [0002] The initial alignment technology is one of the key technologies of strapdown inertial navigation technology, and the improvement of alignment accuracy is conducive to the improvement of the calculation accuracy of strapdown inertial navigation. At present, the commonly used strapdown inertial navigation initial alignment technology is mainly divided into two processes: coarse alignment and fine alignment, and the alignment accuracy of fine alignment largely depends on coarse alignment. The alignment accuracy has high practical significance. Commonly used strapdown inertial coarse alignment methods include analytical coarse alignment, inertial system coarse alignment and solidification analytical coarse alignment. Among these three methods, soli...

AI Technical Summary

Problems solved by technology

However, in the solidification analytical coarse alignment, when calculating the transformation matrix between the carrier coordinate system and the solidification inertial system, the gyro update method is directly used, which does not have a great impact on the optical fiber and laser gyro with high precision and small bias , but for MEMS gyroscopes, the attitude matrix is ​​directly updated, so that its calculation accuracy is directly affected by the gyroscope zero bias, resulting in a decrease in alignment accuracy

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