Underwater carrier initial alignment method based on DVL assistance and vector truncation K matrix

Abstract

The invention discloses an underwater carrier initial alignment method based on Doppler Velocity log (DVL) assistance and a vector truncation K matrix, and the method comprises the steps: obtaining the data of each sensor, and carrying out the preprocessing of the data; calculating an observation vector and a reference vector according to sensor data, and establishing a state matrix equation and a measurement matrix equation of a K matrix; vectorizing the state matrix equation and the measurement matrix equation by using the zero trace property and the symmetry of the K matrix, and then cutting off the vectorized state matrix equation and the measurement matrix equation; then estimating an optimal K matrix by using Kalman filtering; extracting an optimal quaternion from the optimal estimation K matrix, and converting the optimal quaternion into an attitude matrix equation; and finally, utilizing an attitude matrix chain equation to obtain an attitude matrix at the current moment, calculating a misalignment angle, and completing an initial alignment process. According to the method, a traditional initial alignment frame is broken, coarse alignment and fine alignment processes are not distinguished any more, a large misalignment angle and a small misalignment angle are not distinguished any more, and the convergence speed and precision of initial alignment are improved.

Description

technical field [0001] The invention relates to an optimal K-matrix attitude estimation method based on a Wahba problem in the technical field of initial alignment of a navigation system, in particular to an initial alignment method for an underwater vehicle based on DVL assistance and vector truncated K-matrix. Background technique [0002] Ocean observation is the basic means of understanding the ocean and the basis for marine economic development, environmental protection and rights protection. Implementing the "transparent ocean" strategy, strengthening the development of ocean observation technology and equipment, and accelerating the construction of ocean observation systems are an important direction for ocean science and technology innovation at present. As an important equipment of ocean observation technology, autonomous underwater vehicle (AUV) has attracted extensive attention of researchers due to its good concealment and the ability to replace humans to perform...

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Problems solved by technology

[0006] Purpose of the invention: In order to overcome the shortcomings of the Optimal-REQUEST algorithm relying on a conservative estimated performance index and scalar gain to estimate the K matrix when the underwater carrier is initially aligned, the present invention provides a method based on DVL assistance and vector truncation The K-matrix initial alignment method for the underwater vehicle vectorizes the K-matrix state-space equation, and uses the linear correlation between K-matrix elements to truncate to obtain the state vector, and then applies the Kalman filter to complete the alignment. The initial alignment process of the underwater vehicle solves the initial alignment problem when the measurement vector is affected by noise

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