Quick initial alignment method for moving base of SINS (strapdown inertial navigation system) based on lie group description

Abstract

The invention discloses a quick initial alignment method for a moving base of an SINS (strapdown inertial navigation system) based on lie group description. The method comprises the following steps: replacing traditional quaternion description with lie group description to realize calculation of SINS attitude transformation; establishing a linear initial alignment model by using a lie group differential equation; establishing an augmented initial alignment model by taking gyroscopic drift as an augmented state quantity; and then realizing synchronous estimation of an initial attitude matrix and gyroscope constant drift by adopting a matrix-form Kalman filtering algorithm. According to the quick initial alignment method, the gyroscope constant drift is taken as the augmented quantity, and compared with a traditional initial alignment model, a more accurate augmented linear alignment model is established. The alignment method disclosed by the invention can realize one-step direct alignment of the SINS, greatly shortens the alignment time, is convenient for compensating errors in a strapdown resolving process, effectively improves the alignment precision, and is more suitable for practical engineering application.

Description

technical field [0001] The invention discloses a fast initial alignment method for a moving base of a SINS strapdown inertial navigation system described by Li Qun, which belongs to the technical field of navigation methods and applications. Background technique [0002] The so-called navigation is the process of correctly guiding the carrier along the predetermined route with the required accuracy and within the specified time to guide the carrier to the destination. The inertial navigation system calculates various navigation parameters of the carrier based on the output of its own sensors and based on Newton's second law. It is an autonomous navigation system that does not rely on external information and does not radiate any energy to the outside world during work. It has good concealment and strong anti-interference performance, and can provide complete movement information for the carrier all day and all weather. [0003] The early inertial navigation system was mainl...

AI Technical Summary

Problems solved by technology

The purpose of the present invention is to deal with the problems existing in the existing moving base auxiliary alignment method: (1) the present invention describes the initial attitude matrix by Lie groups instead of quaternions, avoiding the non-uniqueness and non-uniqueness of the traditional quaternion description method Non-linear problems; (2) The present invention uses Lie group differential equations to establish a linear initial alignment model, which realizes a one-step direct self-alignment process of SINS. Compared with the existing two-step alignment method, the alignment time can be greatly shortened and improve the alignment accuracy; (3) the present invention uses the gyroscope constant value drift as an augmented state quantity to establish an augmented initial alignment model, which can effectively avoid the model error that the traditional initial alignment model does not consider the gyroscope constant value drift , at the same time, the constant value drift of the gyroscope can be estimated online synchronously, which is convenient for compensating the error in the strapdown solution process

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