Standard-free system grade calibration method of strapdown inertial navigation system

Abstract

The invention discloses a standard-free system grade calibration method of a strapdown inertial navigation system, wherein the method comprises the following steps of 1, building an inertial navigation calibration compensation model; 2, building an inertial navigation calibration compensation error model; 3, performing calibration order transfer compiling and data collection; 4, performing compensation error resolving and correction. By aiming at the two defects of at least square identification method, the standard-free system grade calibration method of the strapdown inertial navigation system is designed; under the standard-free condition, the high-precision calibration of the inertial navigation at different initial postures can be realized.

Description

technical field [0001] The invention relates to a navigation technology, in particular to a system-level calibration method for a strapdown inertial navigation system without reference. Background technique [0002] The calibration method of strapdown inertial navigation system (hereinafter referred to as inertial navigation system) has two directions: discrete and system-level calibration methods. Discrete calibration generally needs to be completed under laboratory conditions, and requires high-precision and three-axis benchmarks. The turntable has high requirements on the accuracy of calibration equipment, high calibration cost, and lower calibration accuracy than system-level calibration. [0003] The system-level calibration has high precision and requires low accuracy of the turntable. Some system-level calibration methods do not even need a turntable, and high-precision calibration can be achieved only by manually flipping the inertial navigation system. At present, ...

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Problems solved by technology

[0008] The system-level calibration method based on least squares identification needs to be carried out under static conditions, but it can overcome other shortcomings of the kalman filter calibration method: (1) It is suitable for the calibration of medium-precision inertial navigation (gyro bias stability is better than 0.5° / h ); (2) A two-axis low-precision turntable can be used, and the inertial navigation can also be installed on a low-precision tooling, and the calibration can be achieved by manual flipping; (3) The sequence of rotation is relatively simple and intuitive; (4) The rotation inside and outside during the calibration process Lever arm effect, gyroscope and accelerometer data asynchrony will not affect the calibration accuracy

[0010] However, the current system-level calibration based on least squares identification needs to meet two requirements in the application: (1) the horizontal and north azimuth reference errors must be within 3°; (2) the initial attitude and rotation sequence of the inertial navigation system are fixed and cannot be changed , otherwise the calibration cannot be achieved

[0011] For these two requirements, unless it is under laboratory environmental conditions, it is difficult to meet these two requirements under most conditions in practical applications, which limits the scope of application of this calibration method

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