SNR modeling for ground-based daytime imaging of GEO-satellites in the SWIR

摘要

This research outlines the expected performance and limitations of a ground-based shortwave infrared (SWIR) sensor in performance of the daytime geosynchronous satellite (GEO) custody mission with a generalized signal-to-noise ratio (SNR) approach model. Ground-based SWIR imaging is a low-cost and informative method of daytime GEO detection and characterization. Previous research has shown that the observed daytime signal from GEOs persists in the SWIR through twilight. Imaging in the SWIR requires only moderately sized telescopes (≤ 1m) and relatively low-cost sensors, therefore large numbers of imaging assets are potentially available. Extending the daytime custody window further into twilight hours by even a few minutes increases vital space situational awareness (SSA) and provides valuable information for future SSA architecture development. This research shows the projected benefits of SWIR-band imaging over visible by GEO-belt position and season for daytime GEO satellite custody. Radiometric models of the satellite signal are developed assuming Lambertian reflectance and generalized satellite geometry. Sky radiance estimates are modeled using atmospheric scattering effects from the Laser Environmental Effects Definition and Reference (LEEDR) tool. The satellite spectral signal is compared to the sky background assuming background limited detection to determine SWIR bands of interest in terms of SNR. SNR trends for daytime custody of a generalized GEO satellite are presented for a full year using Dayton, OH as a representative ground site.