Method for linear alignment of large azimuth misalignment angle

Abstract

The invention relates to a method for linear alignment of a large azimuth misalignment angle. The method comprises the following steps of (1) according to a state equation and an observing equation of a coarse alignment system, utilizing GPS (global positioning system) observing information to realize the coarse alignment process through linear Kalman filtering, until the heading error angle meets the small-angle threshold value condition; (2) reserving a system covariance matrix in convergence of coarse alignment, and using as the initial condition of fine alignment process; (3) continuing to use the system state variable of the coarse alignment, the position and speed error equations and the observing equations, using an attitude error equation, and using the stored covariance matrix as the initial condition to perform fine alignment, until the system is converged to the estimated level. The method has the advantages that the covariance matrix of the system error is directly transferred from the coarse alignment model to the fine alignment model, the stable model switching process is realized, and the convergence process of fine alignment is improved.

Description

technical field [0001] The invention relates to a linear alignment method with a large azimuth misalignment angle, belonging to the technical field of inertial navigation. Background technique [0002] Initial alignment is a key technology of inertial navigation and one of the key technologies of INS / GNSS integrated navigation. In the MEMS-INS / GNSS integrated navigation system, due to the limitations of MEMS devices, especially the gyroscope, it is impossible to initialize the azimuth misalignment angle through self-alignment, resulting in a large azimuth misalignment angle problem. One of the solutions The method is to directly align the moving base. [0003] Establishing accurate INS error propagation equations and adopting appropriate filtering techniques are the main issues for initial alignment. In the case of a large azimuth misalignment angle, the moving base alignment model is essentially nonlinear, and nonlinear filtering is not suitable for engineering applicatio...

AI Technical Summary

Problems solved by technology

[0006] The technical solution of the present invention is to overcome the problem of unstable transition in the switching between rough alignment and fine alignment models in the prior art, and provide a new type of linear alignment method with large azimuth misalignment angle, so that the covariance matrix of the system error can be Transfer directly from the coarse alignment model to the fine alignment model to achieve a smooth model switching process and improve the fine alignment convergence process

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