Star sensor and gyro combination attitude determination method based on SR-UKF (extended Kalman filter) filtering

Abstract

The invention discloses a star sensor and gyro combination attitude determination method based on SR-UKF(extended Kalman filter) filtering, and belongs to the technical field of high-precision combined attitude determination of cartographic satellite or other space vehicles. The invention aims at providing the star sensor and gyro combination attitude determination method based on SR-UKF filtering. An SR-UKF filtering algorithm is used for star sensor and gyro combination attitude determination; great improvement is realized on the existing conventional EKF filtering method. The method concretely comprises the following steps of 1, simulating the star sensor quaternion number and gyro angle speed; 2,using the error quaternion number and gyro random drift error as state variables; using theSR-UKF algorithm for realizing the fusion processing of the star sensor and gyro attitude information for filtering processing; performing feedback; possibly eliminating the error influence of the star senor and gyro error influence through iteration wave filtering processing; solving high-precision attitude information.

Description

technical field [0001] The present invention relates to a satellite star sensor and gyroscope combination attitude determination method, in particular to a star sensor and gyroscope combination attitude determination method based on SR-UKF filtering, which can be used for high-precision combination determination of surveying and mapping satellites or other spacecraft. posture. Background technique [0002] In order to obtain the attitude information of the ground camera at any shooting moment, the high-precision stereoscopic mapping satellite usually uses a star sensor and a gyroscope to form an attitude measurement system. The advantage of the gyroscope is that the acquired angular velocity information has high accuracy within a certain time range and has excellent real-time performance, but its disadvantage is that a certain measurement error will occur as time increases. Xingmin can obtain high-precision attitude information, but its frequency lower. The combined applic...

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Problems solved by technology

[0005] In terms of satellite combination attitude determination technology, the Extended Kalman Filter EKF (Extended Kalman Filter) method has been used in the past. EKF is a representative of traditional nonlinear estimation. Its basic idea is to locally linearize the nonlinear state function and measurement function. That is, the first-order Taylor polynomial expansion is carried out, and then the linear system Kalman filter formula is applied. Although EKF has been widely used, it still has its own insurmountable theoretical limitations: ① It is required that the state function and measurement function of the nonlinear system must be continuous Differentiable, which limits the scope of application of EKF; ②The accuracy of the first-order linearization approximation to nonlinear functions is low, especially when the system has strong nonlinearity, the estimation accuracy of EKF is severely reduced, or even diverges; ③Need to calculate The Jacobian matrix of nonlinear functions is likely to cause poor numerical stability of EKF and calculation divergence

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