A Coarse Alignment Method for Inertial Navigation System on Rocking Base Based on Rotation Modulation

Abstract

The invention provides a rotating modulation-based rocking base inertial navigation system coarse alignment method which can be used for improving the accuracy of coarse alignment in case of a rocking base. The method comprises the following steps: 1, periodically rotating double shafts of a rotary inertial navigation system according to a preset rotation scheme in a coarse alignment process; 2, solving an attitude matrix estimated value of IMU (Inertial Measurement Unit) in each sampling period of the IMU by using an analytic method; 3, performing attitude matrix updating in each sampling period according to angular velocity output by a gyroscope to solve a direction cosine matrix from a local solidification IMU coordinate system to an IMU coordinate system at the current moment; 4, solving an estimated value of the constant direction cosine matrix from the local solidification IMU coordinate system to the IMU coordinate system in the sampling period; 5, solving a final estimated value of the direction cosine matrix from the local solidification IMU coordinate system to the IMU coordinate system; 6, obtaining the attitude matrix of the IMU at the end moment of the coarse alignment.

Description

technical field [0001] The invention belongs to the technical field of strapdown inertial navigation systems, and relates to a rough alignment method for a swing base inertial navigation system based on rotation modulation. Background technique [0002] The initial alignment process of the strapdown inertial navigation system is divided into two stages: coarse alignment and fine alignment. The main task of the coarse alignment is to estimate the approximate value of the attitude matrix, and provide a basic reference mathematical platform for the strapdown inertial navigation system; in the fine alignment stage, the error of the attitude matrix is ​​further estimated by state filtering and other methods, so as to obtain a more accurate mathematical platform, based on which the navigation solution is performed. The accuracy of coarse alignment will affect the convergence speed and accuracy of fine alignment, which in turn affects the accuracy of navigation calculations. There...

AI Technical Summary

Problems solved by technology

However, this method can only suppress the zero offset of some channels, and the introduction of filters will increase the calculation amount of coarse alignment, thereby increasing the complexity of the navigation system and affecting the real-time alignment

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