SINS strapdown inertial navigation system shaking base self-alignment method based on Lie group optimal estimation

Abstract

The invention discloses an SINS strapdown inertial navigation system shaking base self-alignment method based on Lie group optimal estimation, which adopts Lie group description to replace traditionalquaternion description to realize calculation of SINS attitude transformation, and utilizes a Lie group differential equation to establish a linear initial alignment filtering model based on the Liegroup description. And performing equivalent transformation on the state-related error by utilizing the left multiplication invariance of the plum group and the exponential mapping between the plum group and the plum algebra, establishing an equivalent state-independent plum algebra filtering equation, and estimating the initial attitude through the equivalent equation. According to the method, the state-dependent noise under the Lie group model is equivalent to the state-independent noise under the Lie algebra, compared with a traditional Lie group model, a more accurate Lie group linear alignment model is established, and the problems of non-uniqueness and nonlinearity caused by the fact that a traditional quaternion describes an initial attitude matrix are avoided. The method greatly shortens the alignment time, effectively improves the alignment precision, and is more suitable for practical engineering application.

Description

technical field [0001] The invention discloses an initial alignment method of a strapdown inertial navigation moving base based on Lie group description, which belongs to the technical field of navigation methods and applications. Background technique [0002] The so-called navigation is the process of correctly guiding the carrier along the predetermined route with the required accuracy and within the specified time to guide the carrier to the destination. The inertial navigation system calculates various navigation parameters of the carrier based on the output of its own sensors and based on Newton's second law. It is an autonomous navigation system that does not rely on external information and does not radiate any energy to the outside world during work. It has good concealment and strong anti-interference, and can provide complete motion information for the carrier all day and all weather. [0003] The early inertial navigation system was mainly based on platform inert...

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Problems solved by technology

(3) The present invention is based on the initial alignment method of the strapdown inertial navigation moving base described by Li Qun, which can effectively avoid the complex expression problem and a large number of problems caused by the conversion of the quaternion to the attitude matrix in the existing quaternion Kalman filter method. Calculate the error, and can avoid the problem that the orthogonality of the rotation matrix cannot be guaranteed due to the additive error and the calculation error in the Lie group filtering method

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