Secondary transfer alignment method based on double-model switching

Abstract

The invention provides a secondary transfer alignment method based on double-model switching. The secondary transfer alignment method includes following steps: (1) sending a navigation parameter from a main inertial navigation system to a sub inertial navigation system in a fixed frequency; (2) completing coarse alignment by the sub inertial navigation system through the navigation parameter from a main inertial navigation system; (3) constructing an observation quantity by the sub inertial navigation system on the basis of the navigation parameter from a main inertial navigation system; (4) performing iterative calculation under a quaternion error model through an extended Kalman filter; (5) performing filter switching when a misalignment angle is reduced to a preset angle [alpha]; (6) performing iterative calculation under an Euler angle error model through a standard Kalman filter until an estimated value of the misalignment angle is convergent and stable; and (7) by means of the estimated misalignment angle, correcting an attitude matrix of the sub inertial navigation system to obtain a strapdown initial attitude matrix for completing secondary transfer alignment. The method has advantages of quick convergent speed, high precision of a linear model filter and a wide usage scope of a non-linear model filter. Meanwhile, the method can satisfy requirements, including speedability, accuracy and robustness, of a system.

Description

technical field [0001] The invention belongs to the technical field of inertial navigation systems, in particular to a secondary transfer alignment method based on dual-model switching. Background technique [0002] The transfer alignment is to match the navigation parameters such as speed and attitude of the main and sub-inertial navigation systems, and filter and estimate the misalignment angle of the sub-inertial navigation system relative to the main inertial navigation system, so as to establish an accurate sub-inertial navigation mathematical platform, and simultaneously The process of initializing the navigation information of inertial navigation. [0003] At present, the rapid transfer alignment technology under the condition that the misalignment angle is small is relatively mature, and can meet the requirements in terms of speed and accuracy. However, in engineering applications, it often occurs that the misalignment angle is a large angle. In this case, the trad...

AI Technical Summary

Problems solved by technology

[0005] The present invention aims at the problem of fast and accurate transfer alignment when there is a large misalignment angle in the alignment of the inertial navigation system's moving base, and proposes a secondary transfer alignment method based on dual-model switching

Images