News:
All Altitude Atmospheric RT Algorithm for Scene Generation
MDA has need for rapid and accurate scene generation codes. The current highly accurate state-of-the-art SAMM2 (SHARC and MODTRAN Merged 2) is limited in two ways: (1) it is designed to compute a single line-of-sight as opposed to scenes and (2) its core numerical algorithm is geared toward reproducing the exact line-by-line result as opposed to being optimized for speed. This Phase II addresses both technical limitations. To address scene generation requirements, SAMM2 will be upgraded to efficiently compute collections of related lines-of-sight. These upgrades will constitute additional functionality. No existing capabilities will be eliminated. To address computational requirements, SAMM2 will gain a collection of fast new radiation transport algorithms. These algorithms will be constructed either in-house or by third-party developers and will integrate into SAMM2 through a software interface. Within SAMM2, the algorithms will operate at varying degrees of speed and fidelity. Collectively, these algorithms will allow MDA to select the mix of speed and fidelity appropriate for any given problem with all algorithms operating within a single, physically consistent background code.
A comparison between one of these new algorithms and existing codes is shown below.
Point-to-point transmission calculation in the CO2 4.3 micro-meter band. The nadir, nighttime path has the observer located at 300 km and the source located at 100 km (left) and 20 km (right). The red curves correspond to standard Air Force radiation transport codes: SHARC (left) for upper altitude cases and MODTRAN (right) for lower altitude cases. The blue curves correspond to the SAMM2 correlated-k algorithm results.