Nonlinear initial alignment method for all-altitude strapdown inertial navigation system

A technology of strapdown inertial navigation and initial alignment, applied in the fields of guidance and control, and navigation, it can solve the problems of different singular points and so on.

Active Publication Date: 2016-11-23
SOUTHEAST UNIV
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Problems solved by technology

However, there is a singularity problem in the Euler angle attitude representation method. According to the rotation sequence, the singularity points of different Euler angle combinations are different.

Method used

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  • Nonlinear initial alignment method for all-altitude strapdown inertial navigation system
  • Nonlinear initial alignment method for all-altitude strapdown inertial navigation system
  • Nonlinear initial alignment method for all-altitude strapdown inertial navigation system

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Embodiment Construction

[0081] The present invention will be further described below in conjunction with embodiment and accompanying drawing.

[0082] Step 1. Strapdown inertial navigation system coarse alignment: According to the angular velocity information measured by the inertial device gyroscope and the specific force information measured by the accelerometer, use the solidification analytical coarse alignment algorithm based on the gravity acceleration of the inertial system to obtain a rough Initial pitch angle θ in positive Euler angles 0 , roll angle γ 0 and heading angle ψ 0 ;

[0083] Step 2, the initial pitch angle θ obtained according to the step 1 0 , set the operating flag of the forward / inverse Euler angle direct method: if θ 0 ∈[-45°,+45°], then Flag=0, adopt the direct method of positive Euler angle; if θ 0 ∈[-90°,-45°)∪(45°,+90°], then Flag=1, using the direct method of inverse Euler angles;

[0084] Step 3. Initialization of the forward / inverse Euler angle direct method nonl...

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Abstract

The invention discloses a nonlinear initial alignment method for an all-altitude strapdown inertial navigation system, including the main steps of roughly aligning the strapdown inertial navigation system; initiating a double-Euler-angle direct method nonlinear filter of the strapdown inertial navigation system, updating time, measuring measurements, and switching forward and reverse Euler-angle direct methods. The double-Euler-angle direct method and the direct method are fused, the problem of singularity in the single-Euler-angle direct method is solved, the nonlinear initial alignment method is applicable to cases with high carrier dynamics; system equations are mainly velocity differential equations and Euler-angle differential equations, and models are more precise than first approximation of the direct method; navigation resolution is implemented in the filtering process, filtering outputs are navigation parameters, repeated calculations in mechanically arranged equations are avoided, and an algorithm is simpler than the direct method; compared with quaternion direct method, the nonlinear initial alignment method has no need for filtering step modification, and the algorithm is simple.

Description

technical field [0001] The invention relates to a nonlinear initial alignment method of a strapdown inertial navigation system with full attitude, which is used for determining the initial attitude of the strapdown inertial navigation system, and belongs to the technical field of navigation, guidance and control. Background technique [0002] The strapdown inertial navigation system needs to carry out the initial alignment process before entering the navigation work, and its main task is to determine the initial attitude, that is, to determine the initial mathematical platform. [0003] The initial alignment generally needs to go through two stages of coarse alignment and fine alignment. In the coarse alignment stage, the rough initial attitude information is obtained through the angular velocity information measured by the gyroscope and the specific force information measured by the accelerometer. The fine alignment stage generally adopts the optimal estimation filtering me...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01C25/00
CPCG01C25/005
Inventor 程向红冉昌艳
Owner SOUTHEAST UNIV
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