Fast Line-of-Sight Illumination Calculations for Urban Environments

Model simulations have become increasingly valuable for assessing effectiveness and vulnerability in sensor system development and operations planning. A problem of current and critical interest is the performance of Gen III Night Vision Goggles in the urban environment. The Army’s current operational nighttime illumination model only treats lunar illumination in open terrain. Therefore, a quantitative engineering-level model is needed that captures the complexities of the urban environment, particularly in non-ideal (e.g., foggy) weather conditions, and is computationally fast, allowing for insertion into higher-level simulation software. To address this challenge, Spectral Sciences, Inc. proposes to develop a novel Fast Line-of-sight Illumination Calculation (FLIC) model for the visible through near infrared region. The FLIC approach involves pre-computation of key illumination and multiple scattering-related quantities, enabling real-time line-of-sight radiance integration for a specified observer-target pair. A forward-propagating Monte Carlo approach will provide efficient and accurate pre-computation of multiple scattering source functions. Phase I will feature development of the underlying radiative-transfer algorithms, feasibility demonstration for an example scenario, and validation. The end product of Phase I/II/III would be a FLIC algorithm integrated into the Army’s weapons system and mission evaluation software tools, TAWS and IWARS.