Automated Attitude Estimation from ISAR Images

Determining the kinematic state of objects in space is a topic of major concern for both researchers and spacecraft operators. The scientists and engineers are, e.g., interested in the influence of the attitude changes on the orbit of the object, be it for long-term propagations of the state vector or for re-entry predictions, driven by the varying geometric cross-section. For the operators the capability becomes highly important in the case of contingency situations, when communications with the satellite might be lost and solutions have to be found. Different approaches are currently being explored, such as laser ranging, light-curves or Inverse Synthetic Aperture Radar (ISAR) techniques. Our work focuses on the latter, in which the apparent motion of the object with respect to a single radar station is used to determine the geometry and motion of the reflecting object. This paper presents the analysis and results of applying computer vision techniques to estimate the pose of a space object only from ISAR images.