SINS (strapdown inertial navigation system) initial alignment method based on earth rotation angular rate constraint

Abstract

The invention relates to an SINS (strapdown inertial navigation system) initial alignment method based on earth rotation angular rate constraint. The method adopts a Kalman filtering technique for alignment. On the basis of the traditional speed error measuring model, earth rotation angular rate is added as a constraint condition to obtain an improved initial alignment error model. The error model improves the observability of a system during stationary base alignment. By conducting Kalman filtering based on the model to estimate the attitude misalignment angle, the speed error, the gyroscope constant drift and the accelerometer constant bias of the system, the initial attitude and skyward gyroscope drift of the SINS can be obtained more rapidly and accurately. The SINS initial alignment method based on earth rotation angular rate constraint has the characteristics of autonomous navigation, high accuracy, high flexibility, simplicity and convenience, and is suitable for all kinds of medium-accuracy and high-accuracy SINSs.

Description

technical field [0001] The invention relates to a SINS initial alignment method based on the earth rotation angular rate constraint, which belongs to the technical field of inertial navigation, and can be widely used in the initial alignment of various medium and high-precision SINS, effectively improving the observability of the system, thereby improving the Accuracy of initial alignment. Background technique [0002] The basic principle of the strapdown inertial navigation system (Strapdown Inertial Navigation System, SINS) is based on the law of mechanics of relative inertial space proposed by Newton, using gyroscopes and accelerometers to measure the angular motion and linear motion parameters of the carrier relative to the inertial space. The coupled inertial navigation formulates equations, performs corresponding integral calculations, and continuously and real-time provides navigation information such as position, speed, and attitude. Since SINS completely relies on ...

AI Technical Summary

Problems solved by technology

To solve the problem of low observability of the existing initial alignment system, by using the feature that SINS only measures the angular rate of the earth's rotation under static conditions, the measurement error of the angular rate of the earth's rotation is added as the observation quantity, which improves the observability of the initial alignment of the SINS , so that the celestial misalignment angle error can be quickly converged, and at the same time, the north gyro and celestial gyro drift can be quickly and accurately estimated, which improves the initial alignment speed and accuracy of SINS, and also improves the calibration accuracy of inertial devices

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