Novel CKF(Crankshaft Fluctuation Sensor)-based SINS (Ship Inertial Navigation System) large misalignment angle initially-aligning method

Abstract

The invention aims at providing a novel CKF(Crankshaft Fluctuation Sensor)-based SINS (Ship Inertial Navigation System) large misalignment angle initially-aligning method comprising the following steps of: determining an initial position parameter of a carrier by using a GPS (Global Position System); acquiring data output by an optical fiber gyroscope and a quartz accelerometer; finishing the coarse alignment of the system by using an analysis method; preliminarily determining the posture information of the carrier; establishing an initial aligning nonlinear model of a strapdown inertial navigation system; establishing a CKF filtering state equation by taking the speed error as the state variable and a measuring equation by taking the speed error as the measurement quantity under a static base; carrying out filtering estimation by using a CKF filtering method to estimate the misalignment angle of the platform; and obtaining an accurate strapdown initial posture matrix by using a strapdown initial posture matrix of a platform misalignment angle correcting system, thereby finishing the accurate initial alignment. The invention can greatly improve the aligning precision of the strapdown inertial navigation system at the large misalignment angle and provide the accurate strapdown initial posture matrix for the navigation process.

Description

technical field [0001] The invention relates to an initial posture alignment method used in the navigation field. Background technique [0002] Initial alignment is one of the key technologies of Strapdown Inertial Navigation Systems. The initial alignment accuracy directly affects the working accuracy of the strapdown inertial navigation system, and the initial alignment time is also an important tactical indicator reflecting the system's rapid response capability. The main purpose of the initial alignment of the strapdown inertial navigation system is to establish the initial value of the attitude matrix. In the initial alignment, the initial alignment state space model is used to estimate the initial misalignment angle state by Kalman filter and used to correct the attitude matrix. The traditional alignment process includes two stages: coarse alignment and fine alignment. First, the rough alignment model is used to roughly estimate the size of the misalignment angle, and...

AI Technical Summary

Problems solved by technology

The strict mathematical error model of the strapdown inertial navigation system is a set of nonlinear differential equations. In the error model of the small misalignment angle strapdown inertial navigation system, a set of linear differential equation error models are derived based on the Φ angle method or the Ψ angle method. Obviously, there must be some modeling errors when using a linear model to approximate a nonlinear model

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