A method for evaluating the alignment accuracy of an inertial navigation system

Abstract

The invention discloses an inertial navigation system alignment accuracy evaluation method. The method comprises the following steps: with differential GPS speed as external reference base, constructing an inertial navigation system alignment accuracy evaluation observation quantity, and performing extended Kalman filter calculation in combination with an inertial navigation system alignment accuracy evaluation nonlinear model; after each extended Kalman filter calculation cycle, inserting the calculation of an extended fixed-interval smoothing gain matrix, and storing the filter data in real time until the filter calculation is over; and performing reverse extended fixed-interval smoothing calculation by use of the stored filter data, and estimating the attitude misalignment angle at the moment when the inertial navigation system alignment is over to realize evaluation of the inertial navigation system alignment accuracy. The method can realize inertial navigation system alignment accuracy evaluation in the conditions of large azimuth misalignment angle and small misalignment angle, and has the advantages of strong robustness, small data storage capacity and high calculation efficiency.

Description

technical field [0001] The invention relates to the field of inertial navigation systems, in particular to an evaluation method for the alignment accuracy of an inertial navigation system with strong robustness. Background technique [0002] The inertial navigation system has high-precision attitude measurement, speed measurement and positioning functions. But as a dead reckoning method, the inertial navigation system must be initially aligned to complete the initialization of the inertial navigation system. The most critical thing in the initial alignment is the attitude alignment, which is to align the calculated coordinate system of the inertial navigation system with the northeast sky coordinate system. The most effective way to measure the alignment performance is to evaluate the alignment accuracy performance and obtain the attitude misalignment angle at the end of the alignment, that is, the attitude deviation angle of the coordinate system calculated by the inertial...

AI Technical Summary

Problems solved by technology

However, there is no research on the evaluation of alignment accuracy under the condition of large azimuth misalignment angle

In recent years, when the inertial navigation system is aligned under the condition of a real large azimuth misalignment angle, due to the limitation of azimuth alignment performance, the residual attitude misalignment angle after alignment still shows a large azimuth misalignment angle. The actual model of the system is nonlinear, and the effective evaluation of the azimuth misalignment angle cannot be achieved if the existing alignment accuracy evaluation method is applied

On the other hand, the calculation of the fixed interval smoothing algorithm is carried out after the filtering solution, which needs to store a large amount of data, and the calculation efficiency is poor

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