Change search
ReferencesLink to record
Permanent link

Direct link
Development, Implementation and Testing of Two Attitude Estimation Methods for Cube Satellites
Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, Department of Engineering Cybernetics.
Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, Department of Engineering Cybernetics.
2011 (English)MasteroppgaveStudent thesis
Abstract [en]
As a part of the CUBESAT project at the Norwegian University of Science and Technology (NTNU), this paper studies development and comparison of attitude estimation methods for small cube satellites using low-cost sensors. The algorithms are based on data from two vectorized measurements as well as a gyroscope. In this paper a new method for attitude estimation has been de- veloped based on QUaternion ESTimation (QUEST). A major concern with QUEST is that it cannot handle non-vectorized measurements such as gyroscope data. Substantial improvements have been made to fuse vectorized and non-vectorized measurements, making the new Extended QUaternion ESTimation (EQUEST) more suitable for attitude estima- tion. The well known Extended Kalman Filter (EKF) is derived and implemented for comparison. Both methods have been developed and simulated in MATLAB. The code have been rewritten using C language. The methods are compared both theoretically and experimentally with implementation and testing on an AVR microcontroller. Minimum power usage and number of arithmetic operations were considered during the software development. Testing indicates that the EKF provides a smoother estimation than the newly developed EQUEST. In contrast to EQUEST, the EKF is able to estimate the magnetometer and accelerometer bias. However, the EQUEST has a signicantly faster settling time and is less computational costly. Compared to the EKF, EQUEST runs more than 5 times faster. It also requires only 8% of the arithmetic operations of the EKF. Another disadvantage with the EKF is tracking problems that occur when the two vectorized measurements are close to parallel. With vectors close to paral- lel, the mathematical formulation of the EKF makes tracking of a rotation around the parallel axis extremely dicult. These diculties are hardly observed in the EQUEST algorithm, which makes it very attractive for attitude estimation. The attitude control of CUBESATs is often done by magnetorquers, which will aect the local magnetic eld. Hence, control and estimation should not be done simultaneously, resulting in the estimation and control switching on and o. For this reason, the long settling time of the EKF makes the EQUEST even more attractive. The results in this paper indicate that the newly developed EQUEST is highly suitable for projects with either limited budget, space, weight or computational power.
Place, publisher, year, edition, pages
Institutt for teknisk kybernetikk , 2011. , 119 p.
Keyword [no]
ntnudaim:5925, MTTK teknisk kybernetikk, Reguleringsteknikk
URN: urn:nbn:no:ntnu:diva-13274Local ID: ntnudaim:5925OAI: diva2:436732
Available from: 2011-08-24 Created: 2011-08-24

Open Access in DiVA

fulltext(9304 kB)951 downloads
File information
File name FULLTEXT01.pdfFile size 9304 kBChecksum SHA-512
Type fulltextMimetype application/pdf
cover(91 kB)50 downloads
File information
File name COVER01.pdfFile size 91 kBChecksum SHA-512
Type coverMimetype application/pdf
attachment(463 kB)151 downloads
File information
File name ATTACHMENT01.zipFile size 463 kBChecksum SHA-512
Type attachmentMimetype application/zip

By organisation
Department of Engineering Cybernetics

Search outside of DiVA

GoogleGoogle Scholar
Total: 951 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 121 hits
ReferencesLink to record
Permanent link

Direct link