Dual-Altitude Band Coverage for Spaceborne Optical Sensor with Field-of-View Constraint

Space-based optical monitoring systems have become promising options for space situational awareness with their advantages of observation range, duration, and quality. The dual-altitude band coverage evaluation of optical sensors is fundamental to designing and optimization of such systems. In this study, the dual-altitude band coverage evaluation of a spaceborne optical sensor with a cone field-of-view (FOV) constraint is addressed. Specifically, the target dual-altitude band region is discretized into crescent-shaped volume cells by introducing equidistant nodes along the radial and azimuth directions. When the size of each cell becomes sufficiently thin, the coverage of this cell can be approximated by the coverage of its centerline. Thus, the original dual-altitude band coverage problem is converted into a one-dimensional zenithal angular coverage problem. Then, considering geometric constraints on Earth’s occlusion and thermal background and the cone FOV constraints, we obtained the effective coverage of the azimuthal and zenithal angles of the target region by performing a comprehensive analysis of all 14 possible geometric cases. Alongside a pure coverage volume scoring method, a weighted coverage scoring method is introduced to take account of the nonuniform density distribution of space objects in altitude. Finally, the accuracy of the proposed method is validated by numerical examples.