Temperature calibration method of laser gyro inertia measurement unit

Abstract

The invention provides a method for accurately calibrating temperature error coefficients of a laser gyro inertia measurement unit. In the method, a three-axle table with a thermostate is utilized to enable an LIMU to achieve whole thermal balance through a measure of performing long-term heat preservation at a certain temperature spot; system inherent error coefficients such as a gyro scale factor, a gyro literal drift, an accelerometer scale factor, an accelerometer literal bias and the like at the temperature spot are accurately calibrated through a calibration method of combining dynamic rotation and static 24 position; and then high and low temperature cycling tests are performed on the LIMU by utilizing the inherent error coefficients of the LIMU at the temperature spot, so that the temperature error coefficients comprising 30 temperature related coefficients such as a primary temperature coefficient, a secondary temperature coefficient, a temperature gradient coefficient and a temperature change rate coefficient of the gyro literal drift and accelerometer literal bias are further calibrated. The method provided by the invention has the characteristics of high accuracy and simplicity in operation, and can be used for greatly improving the use accuracy of the LIMU under a variable temperature environment.

Description

technical field [0001] The invention relates to a method for accurately calibrating the temperature error coefficient of a laser gyro inertial measurement unit (Laser Gyro Inertial Measurement Unit, LIMU), which can be used for temperature calibration of the laser gyro inertial measurement unit. Background technique [0002] As an ideal device for inertial navigation, laser gyro has the characteristics of short start-up time, large dynamic range, high reliability, long life, and digital output. In recent years, the laser gyro strapdown inertial navigation system has been successfully used in many fields such as aviation, aerospace, and navigation. The laser gyro inertial measurement unit LIMU is the core component of the laser gyro strapdown inertial navigation system. In many applications, the ambient temperature changes drastically, which directly affects the change of the inherent error coefficient of the LIMU, especially the constant value of the gyro and the constant va...

AI Technical Summary

Problems solved by technology

This method has the following two problems: 1. The system temperature error and the system inherent error are not completely separated, and there is mutual interference; 2. Only the errors in multiple groups of constant temperature environments are calibrated, and the errors in the environment of dynamic temperature changes are not calibrated.

In the actual engineering application environment, the laser gyro inertial measurement unit starts to work when it is powered on. The temperature of the gyroscope and the accelerometer is always in the process of changing. On the one hand, it is affected by the changing external environment temperature. Due to the influence of heat, the gyroscope and accelerometer themselves form a complex temperature field from the inside to the outside, which seriously affects the measurement accuracy of the laser gyroscope and accelerometer, and further affects the use accuracy of the inertial measurement unit.

At the same time, the traditional LIMU temperature calibration method obtains a temperature error model in a constant temperature environment with a limited number of temperature points. It needs to approximate the continuous model by piecewise linear fitting, which brings a large approximation to the temperature error model. error

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