Satellite attitude determining method based on improved self-adaptive square root UKF (Unscented Kalman Filter) algorithm

An adaptive square root and satellite attitude technology, applied to integrated navigators and other directions, can solve the problems of large rounding error satellite attitude determination system, unstable satellite attitude estimation accuracy, low satellite actual state tracking ability, etc., to improve tracking ability , Enhanced tracking ability and good stability

Inactive Publication Date: 2014-07-23
HARBIN INST OF TECH
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  • Abstract
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  • Application Information

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Problems solved by technology

[0004] The purpose of this invention is to propose a satellite attitude determination method based on the improved self-adaptive square root UKF algorithm, to solve when the satellite attitude determination system is affected by uncertainty interference and noise, due to the existing

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  • Satellite attitude determining method based on improved self-adaptive square root UKF (Unscented Kalman Filter) algorithm
  • Satellite attitude determining method based on improved self-adaptive square root UKF (Unscented Kalman Filter) algorithm
  • Satellite attitude determining method based on improved self-adaptive square root UKF (Unscented Kalman Filter) algorithm

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specific Embodiment approach 1

[0013] Specific embodiment one: a kind of satellite attitude determination method based on the improved self-adaptive square root UKF algorithm described in the present embodiment is characterized in that described method comprises the following steps:

[0014] Step 1. Establish a gyroscope measurement model;

[0015] Step 2, establishing satellite attitude kinematic equations;

[0016] Step 3, establishing the system state equation based on the state variable composed of the error quaternion and the gyro drift error;

[0017] Step 4, establishing the error system observation equation;

[0018] Step 5, using the improved adaptive square root UKF to estimate the error quaternion and gyro drift error;

[0019] Step 6. Substituting the gyro measurement value and the estimated gyro drift error into the attitude kinematics equation to calculate the attitude quaternion;

[0020] Step 7, using the estimated error quaternion to correct the attitude quaternion calculated by the solu...

specific Embodiment approach 2

[0022] Embodiment 2: The difference between this embodiment and Embodiment 1 is that the specific process of establishing the gyro measurement model described in step 1 is: when the gyro measurement coordinate system and the coordinate system of the star are the same coordinate system, the gyro The measurement model is

[0023] g ( t ) = ω ( t ) + β ( t ) + η u ( t ) ...

specific Embodiment approach 3

[0027] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is: the specific process of establishing the satellite attitude kinematics equation described in step two is: the satellite attitude quaternion is defined as

[0028] q=[q 1 q 2 q 3 q 4 ] T (3)

[0029] In the formula, q 4 =cos(θ / 2), and θ are unit rotation vector and rotation angle respectively;

[0030] Quaternions satisfy the following constraints:

[0031] q 1 2 + q 2 2 + q 3 2 + q 4 2 = 1 - - - ( 4 )

[0032] The kinematics equation of satellite attitude expressed by quaternion is:

[0033] dq ...

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Abstract

The invention relates to a satellite attitude determining method based on an improved self-adaptive square root UKF (Unscented Kalman Filter) algorithm, which belongs to the technical field of satellite attitude determination and solves the problems that a satellite attitude determining system is unstable, the satellite attitude precision is low, and the traceability to an virtual condition of a satellite is weak due to overlarge round-off errors numerically calculated by virtue of existing EKF (Extended Kalman Filter), UKF (Unscented Kalman Filter) and SRUKF (Square Root Unscented Kalman Filter) algorithms when the satellite attitude determining system suffers from uncertain interferences and is influenced by noise. The satellite attitude determining method comprises the main realization processes: estimating an error quaternion and a gyroscopic drift error by virtue of the improved self-adaptive square root UKF; substituting gyroscopic measurement value and the estimated gyroscopic drift error into an attitude kinematical equation to calculate an attitude quaternion; correcting the calculated attitude quaternion by virtue of the estimated error quaternion; carrying out attitude resolving by virtue of the corrected attitude quaternion so as to determine the attitude of the satellite. The satellite attitude determining method is suitable for the technical field of the satellite attitude determination.

Description

technical field [0001] The invention relates to a high-precision satellite attitude determination method of a star sensor and a gyroscope, and belongs to the technical field of satellite attitude determination. Background technique [0002] The attitude measurement system composed of star sensor and gyroscope is widely used in the satellite attitude determination system because of its high precision. For the nonlinear system composed of it, the method of determining attitude using nonlinear filtering technology is widely used. The Extended Kalman Filter (EKF) is widely used in engineering problems dealing with nonlinear estimation because of its simple method and easy implementation. However, EKF makes a first-order approximation to nonlinear equations and ignores other high-order terms, thereby converting nonlinear problems into linear problems. When the nonlinearity of the system is strong, the EKF violates the local linear assumption, and the neglected high-order terms ...

Claims

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Application Information

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IPC IPC(8): G01C21/24
CPCG01C21/24
Inventor 李敏王松艳张迎春耿云海李华义谢成清
Owner HARBIN INST OF TECH
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