CPI has developed a natural illumination model of the earthshine and skyshine incident on Resident Space Objects (e.g. satellites) to support space-based surveillance for Space Situational Awareness (SSA).The Integrated Sphere Irradiance Software (ISIS) is a full-featured, first-principles model that provides the capability to calculate ultraviolet (UV), visible (VIS), and infrared (IR) irradiance of Resident Space Objects (RSOs) from natural light sources, including irregular and inhomogeneous sources. It supports the testing of space surveillance systems capabilities by assessing the limits that space-based sensors can detect and observe new RSOs under different viewing geometries. ISIS is built upon a variety of existing codes that accurately model different natural illumination sources, and makes extensive use of terrain, cloud, and atmosphere data bases to provide the most accurate inputs for estimating earthshine and skyshine illumination of RSOs. Readily available real-world data from operational space-based sensors are used to generate realistic illumination conditions for specific viewing geometries. This illumination model is embedded into CPI's Shine architecture to facilitate the incorporation of fast scene rendering algorithms developed within the computer graphics community, and to take advantage of massively parallel computing hardware. The result is a high performance computational tool that can be incorporated into SSA simulations.
More details on the modeling capabilities can be found in the Shine/ISIS brochure. \ p>