System performance for all HSI systems is influenced by many factors, including environmental conditions, operational usage, internal system composition and the processing chain. Truly optimizing this performance requires an understanding of the operational conditions under which each system will perform. One of the key factors affecting system performance, especially at long stand-off ranges, is the atmospheric effects. This paper presents analytical results demonstrating the effects of atmospheric conditions on long stand-off airborne HSI systems based on a Raytheon developed performance model for estimating System performance.
This end-to-end System Performance Model is especially designed for long stand-off airborne detection with large off-nadir viewing angles. It takes into account most of the components within the entire imaging chain. The model divides the end-to-end imaging chain into three parts: the environmental component, the Concept of Operations (CONOPS), and the imaging system effects. The environmental component includes solar illumination, reflectance of materials on the ground, scattering, and atmospheric transmittance. The system component includes the effects of system noise and throughput. The CONOPS accounts for the various operating conditions best suited for long stand-off detection. The analytical results presented in this paper provide details on the influence of the atmospheric conditions, including tropical conditions, on NESR and SNR performance in a Spot Mode CONOPS for a HSI system based on the end-to-end System Performance Model. These results are based on continued work developed from the “Long stand-off Performance Modelling of HSI Airborne Imaging Systems”.