Mixed calibration method for Inertial measurement unit capable of eliminating gyro constant drift

Abstract

The invention discloses a method for marking IMU each item error coefficient precisely, which comprises the following steps: marking the gyroscopic scale factor and gyroscopic installment error in the IMU error model through dynamic calibration experiment; substituting the error value in the symmetrical 24 position static calibration experiment of adjacent position; adapting the symmetrical position error cancellation law to mark IMU residual each item error coefficient within gyroscopic constant drift, error item of gyroscope and acceleration, accelerometer constant bias, accelerometer marking factor and accelerometer fixation error.

Description

technical field [0001] The invention relates to an error calibration method of an inertial measurement unit (IMU), which can be used to calibrate a flexible gyro IMU, a liquid floating gyro IMU or a MEMS gyro IMU. Background technique [0002] The inertial measurement unit (IMU) is the core component of the inertial navigation system. Its error includes two parts: deterministic error and random error. Among them, the deterministic error, that is, the system error, accounts for about 90% of the total error. Therefore, the IMU must be established before use to determine The mathematical model of the linear error, and the error coefficients in the model are determined through experiments. This process is called the calibration of the IMU. Traditional calibration methods include rate calibration test method and multi-position static calibration test. The accuracy of rate calibration test is very high, but only part of the error coefficient can be calibrated; multi-position stati...

AI Technical Summary

Problems solved by technology

Traditional calibration methods include rate calibration test method and multi-position static calibration test. The accuracy of rate calibration test is very high, but only part of the error coefficient can be calibrated; multi-position static calibration test usually uses the least square method to process test data, and can calibrate out All the error coefficients, but the accuracy is low, and the least square method makes the unstable gyro constant drift pollute other error coefficients, resulting in inconsistent calibration results obtained by different multi-position test programs, and the difference is very large, called For "inconsistency of error coefficient problem"

Therefore, neither of the traditional two calibration methods mentioned above can complete the precise calibration of the IMU.

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