Geometry of Fan Beam Albedo Measurements on Spin-Stabilized Satellites.

Because there is an imminent danger that most of the existing expert knowledge about attitude determination using fan beam albedo sensors on spin-stabilized satellites may become unavailable, it seems worthwhile to summarize this material in an archival paper. Toward this goal, all still-accessible reports and notes dealing with attitude reconstitution based on albedo slit sensors have been scrutinized. On this basis, we assessed the state of the art that was reached some decades ago; subsequently, no new satellite projects were realized that made use of this still- interesting type of attitude sensors. In the analysis of the available material, it appeared that attitude measurement stability and estimation accuracy still faced problems during particular time periods. In this context, elements have been identified that had been omitted from the ground-based attitude operations. These elements essentially concern the exclusion of specific measurement geometries, which, with certainty, invalidated certain measurements during time intervals of nonnegligible duration. The reported estimation concepts of the past have been updated not only on a theoretical basis, but also in light of more recent insights and operational experience gained from infrared sensing on spinning satellites. All this is included in a comprehensive and self-contained presentation based on the geometry of fan beam albedo sensing and its practical operational implementation. [ABSTRACT FROM AUTHOR]