Signal Conditioning for the Kalman Filter: Application to Satellite Attitude Estimation with Magnetometer and Sun Sensors.
Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework.
Department of Computer Architecture and Automatic Control, Faculty of Physic Sciences, Complutense University of Madrid, Madrid 28040, Spain. segundo@dacya.ucm.es.
Segundo
S
Esteban
Department of Computer Architecture and Automatic Control, Faculty of Physic Sciences, Complutense University of Madrid, Madrid 28040, Spain. gironsi@dacya.ucm.es.
Jose M
JM
Girón-Sierra
Department of Computer Engineering, University of Alcala, Alcalá de Henares 28871, Spain. opolo@aut.uah.es.
Óscar R
ÓR
Polo
Department of Space Programs, INTA, Torrejón de Ardoz 28850, Spain. angulo.manuel2@gmail.com.
Manuel
M
Angulo
Kalman filter; Sun sensors; attitude determination and control; condition number; low cost satellites; magnetometer sensor; quaternion