Coarse Sun Sensor Optimization under the Impact of Albedo
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Coarse Sun Sensors are typically used either to support detumbling or to establish sun-pointing in any safe-mode situation.The concerned Coarse Sun Sensor is based on a truncated pyramid with the detector cells attached to the faces and is commonly only operated in a tiny field of view where all four cells are illuminated. It is aimed to increase this operational field of view while keeping the albedo induced error in Low Earth Orbit missions as low as possible. A new approach for the computation of the sun vector, which is not based on subtraction of opposite cell intensities, is presented. This unique approach is capable of highly enlarging the field of view since it not only allows for a computation of the sun vector with four cells being illuminated by the sun, but also with three- and even two cells.An analysis regarding the optimum pyramid design is carried out and several possibilities for improving the overall accuracy with respect to the influence of albedo are identified.The results demonstrate that previous recommendations regarding the best pyramid tilt angle are not valid for the new algorithms anymore.Concerning nominal operations, thoughts on correcting for the influence of the Earth's albedo using a coarse infrared Earth sensor are presented. Finally, similarities in the mathematical models of both sensors are highlighted.
Place, publisher, year, edition, pages
2015. , 96 p.
Technology, CSS, Safe-Mode, Coarse Sun Sensor, Optimization, Field of view
IdentifiersURN: urn:nbn:se:ltu:diva-50174Local ID: 774580dd-4de4-4396-8dbb-3471ad3c5780OAI: oai:DiVA.org:ltu-50174DiVA: diva2:1023531
Subject / course
Student thesis, at least 30 credits
Space Engineering, master's level
Validerat; 20151013 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved