Initial alignment method of strap-down inertial navigation system based on low-precision micro electro mechanical system

Abstract

The invention relates to an initial alignment method of a strap-down inertial navigation system and particularly relates to the initial alignment method of the strap-down inertial navigation system based on a low-precision micro electro mechanical system (MEMS) under the condition of only utilizing GPS (Global Position System) auxiliary equipment. The initial alignment method comprises the following steps of: obtaining a direction cosine matrix from a carrier coordinate system to a horizontal coordinate system; establishing a coarse alignment Kalman filtering state equation of the strap-down inertial navigation system of the low-precision micro electro mechanical system; establishing a Kalman filtering measurement equation of coarse alignment of the strap-down inertial navigation system of the low-precision micro electro mechanical system; carrying out first-time correction on a carrier posture; establishing a Kalman filtering state equation and a measurement equation of fine alignment of the strap-down inertial navigation system; carrying out second-time Kalman filtering; and carrying out second-time correction on the carrier posture to obtain an accurate strap-down matrix of the strap-down inertial navigation system of the micro electro mechanical system. According to the initial alignment method disclosed by the invention, a method of estimating an error of the strap-down inertial navigation system of the low-precision MEMS by two times of Kalman filtering is utilized to finish the initial alignment of the system, so that the application is convenient.

Description

technical field [0001] The invention relates to an initial alignment method of a strapdown inertial navigation system, in particular to a method for initial alignment of a strapdown inertial navigation system based on a low-precision micro-electromechanical system under the condition of only using GPS auxiliary equipment. Background technique [0002] The main task of the initial alignment is to give the initial attitude matrix of the SINS. The initial alignment of SINS can generally be divided into two stages: coarse alignment and fine alignment. The main task of coarse alignment is to quickly control the attitude error within a relatively small range to create conditions for the next step of fine alignment; the task of fine alignment is to use a linear model to estimate the remaining angle of The error of the joint inertial navigation system is corrected, and the initial value is provided for the next navigation work. [0003] For the initial alignment of high-precision ...

AI Technical Summary

Problems solved by technology

For the low-precision MEMS strapdown inertial navigation system, due to the relatively large drift speed of the gyroscope, generally 1-10deg / h, the earth's rotation angular velocity cannot be measured, so the initial alignment that can be completed by the high-precision strapdown inertial navigation system The method is invalid for the strapdown inertial navigation system of low-precision MEMS (micro-electro-mechanical systems, micro-electro-mechanical systems), and cannot complete the initial alignment

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