NATO STO

The atmosphere has a detrimental effect on effective range and/or resolution of Electro-Optical (EO) sensors (visible to far infrared) and laser systems. Depending on weather and propagation geometry it will vary if it is the atmospheric effects or system design (e.g. diffraction from system aperture and pixel size) that limit system performance. Some atmospheric effects can be compensated for. For example, turbulence-induced degradations can be partially corrected in imaging or laser systems by using hardware- or software-based mitigation techniques. Adaptive Optics (AO) systems are more efficient for laser beam delivery systems, while image processing is more suitable for visible/IR imaging sensors. Scattering and absorption can be mitigated to a certain degree by e.g. post factum contrast enhancement in imaging systems. Previous SET RTG:s (226 and 304) have focused on the effects of optical turbulence on long-range imaging and laser beams. Data has been jointly collected in international field trials in Quebec (Canada) and Le Fauga (France). A challenge on Coded Target Restoration through Atmospheric Turbulence has been organized in collaboration with the Computer Vision and Pattern Recognition (CVPR) conference the premier event in image processing. Within the RTG:s, we have analyzed simplified scenarios of close to ground, horizontal-path propagation in idealized, homogenous conditions. Under these circumstances, significant strides have been made, in understanding atmospheric turbulence and its influence on the metrics relevant to the armed forces. Theories have been either developed or validated. The results of these groups point unequivocally to the correctness of the description of such propagation scenarios and validity of the associated theory. Because of that, analytic tools are now available to the practitioners who want to predict the outcome of the deployment of their EO systems in horizontal paths close to the ground with a known turbulence strength. Participants in the proposed ET will be tasked with analyzing more realistic and more complex scenarios including slant paths and heterogeneous terrain, such as land sea interfaces. Slant-path propagation is relevant for all ground-to-air and air-to-ground scenarios. Especially close-to-ground slant paths to low-flying UAV:s within the envelope of the surface layer will be addressed, motivated by insights gained from the war in Ukraine where UAV:s are flown low to the ground to avoid being targeted. Free space optical communications, power beaming, tracking, target identification and laser directed energy are all important laser and EO sensor applications to either operate your own UAV:s under disruption from electronic warfare or to protect against enemy UAV:s. Additionally, other atmospheric effects beside turbulence, e.g. scattering from aerosols, clouds and atmospheric absorption, will be included. Previous RTGs were broadly conceived and encompassed several subjects such as meteorology, free-space optical communications, high-energy lasers, underwater optical communications, and imaging through turbulence. The primary goal of the proposed ET is to formulate the atmospherics applications and enabling technologies of immediate and pressing interest to the NATO community and to spawn either one or separate RTGs devoted to these applications.