Method for determining initial attitude of fiber strapdown inertial navigation system based on rotating mechanism

Abstract

The invention provides a method for determining the initial attitude of a fiber strapdown inertial navigation system based on a rotating mechanism. The method comprises the following steps: according to the relation between the SINS output and the rotational angular velocity and the acceleration of gravity of the earth, initially determining the SINS initial attitude, and utilizing the Kalman filtering method to estimate a misalignment angle so as to determine the local north orientation; establishing an error model of a fiber optic gyroscope to estimate the north orientation gyroscope drift under the navigation system; after an inertial measurement unit (IMU) clockwise rotates for 90 degrees, estimating the south orientation gyroscope drift under the navigation system; after the IMU horizontal gyroscope drift is obtained, the operation of compensation is carried out; and the technical scheme of initial alignment under the state that the inertial measurement unit rotates around a carrier azimuth axis is adopted for the system after error compensation, so as to determine the initial strapdown matrix of the system and to obtain the attitude of the carrier at the initial time by calculation. The method has the characteristics of automation and high precision, and is suitable for various medium and high precision strapdown inertial navigation systems.

Description

(1) Technical field [0001] The invention relates to a measurement method, in particular to a method for determining the initial attitude of an optical fiber strapdown inertial navigation system based on a rotating mechanism. (2) Background technology [0002] Strapdown Inertial Navigation System (SINS) is to connect inertial components such as gyroscopes and accelerometers to the carrier. According to Newton’s laws of mechanics, the attitude, velocity, position and acceleration of the carrier can be obtained by processing the information collected by these inertial components. , angular velocity and angular acceleration and other full navigation information of fully autonomous navigation equipment. Due to its advantages of light weight, high reliability, easy maintenance, all-weather and full autonomy, it is being used more and more widely. [0003] Calibration technology is essentially an error compensation technology. The so-called error compensation technology is to est...

AI Technical Summary

Problems solved by technology

[0006] Due to the combined alignment with velocity as the observation quantity under the static base, the observability of the system is not high, especially the eastward gyro drift in the geographic coordinate system is not observable, which makes it difficult to improve the observability of the azimuth misalignment angle. The purpose of improving the attitude accuracy cannot be achieved, and the calibration of the gyroscope cannot be achieved at the same time as the initial attitude calculation

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