Correlated-k-based method for fast generation of bandpass radiance and transmittance look-up-tables

The ability to rapidly calculate at-sensor radiance over a large number of lines of sight (LOSs) is critical for scene simulations, which are increasingly used for sensor design, performance evaluation, and data analysis. We have recently demonstrated a new radiation transport (RT) capability that combines an efficient multiple-LOS multiple scattering algorithm with a broad-bandpass correlated- k methodology called k URT-MS. The multiple-LOS capability is based on DISORT and exploits the existing MODTRAN-DISORT interface. k URT-MS is a new sensor-specific correlated- k ( c-k ) ultra-fast radiative transfer formalism for UV-visible to LWIR wavelengths that is derived from MODTRAN's correlated- k parameters. Scattering parameters, blackbody and solar functions are cast as compact k -dependent source terms and used in the radiance computations. Preliminary transmittance results are within 2% of MODTRAN with a two-orders-of-magnitude computational savings. Preliminary radiance computations in the visible spectrum are within a few percent of MODTRAN results, but with orders of magnitude speed up over comparable MODTRAN runs. This new RT capability has potential applications for hyperspectral scene simulations as well as target acquisition algorithms for near earth scenarios.