In-orbit identification of unmodelled disturbance torques acting on a spacecraft body

Author

Engelbrecht, J.A.A. ; Steyn, W.H.

Volume

1

fYear

2004

fDate

17-17 Sept. 2004

Firstpage

3

Abstract

Extended Kalman filters (EKFs) are often used on low earth orbit spacecraft to estimate the attitude from directional vector measurements. These EKFs require a good mathematical model of the attitude dynamics to propagate the attitude estimate. If the model of the attitude dynamics is inaccurate, the EKF may take longer to converge or may not converge at all. Unmodelled disturbance torques need to be identified in order to improve the accuracy of the attitude dynamics model. This paper presents two methods of in-orbit identification of unmodelled disturbance torques acting on a spacecraft body. The first method uses rate sensor measurements combined with measurements from a single directional vector sensor, such as a magnetometer or sun sensor. The second method uses a combination of two non-collinear directional vector sensors, such as a magnetometer combined with a sun sensor

Keywords

Kalman filters; attitude control; attitude measurement; convergence; identification; magnetometers; position measurement; space vehicles; torque measurement; EKF convergence; attitude control; attitude dynamics model; attitude estimation; directional vector measurements; disturbance torque in-orbit identification; extended Kalman filters; low earth orbit spacecraft; magnetometer; noncollinear directional vector sensors; position measurement; rate sensor measurements; spacecraft body unmodelled disturbance torques; sun sensor; Aerodynamics; Covariance matrix; Extraterrestrial measurements; Gyroscopes; Low earth orbit satellites; Magnetic sensors; Magnetometers; Space vehicles; Sun; Torque measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

AFRICON, 2004. 7th AFRICON Conference in Africa

Conference_Location

Gaborone

Print_ISBN

0-7803-8605-1

Type

conf

DOI

10.1109/AFRICON.2004.1406619

Filename

1406619