88 Looking at the various inspection and monitoring missions uncrewed systems carry out these days, it soon becomes clear that thermal imagers have become central to almost every one. Measuring for thermographic differentials across objects, infrastructure and terrain reveals details that are invisible in the visible light spectrum or from 3D Lidar scans, and this can be critical in some circumstances. For instance, aerial photography taken in the long-wave infrared (LWIR) wavelengths of 8-15 µm can show where water is concentrated or absent across swathes of land, which can be vital in agricultural and wildfire monitoring. Also, as contiguous planes or pieces of solid material such as metal or stone will exhibit some homogeneity (or at least continuity) in visible light, thermal cameras can reveal cracks or micro-fractures in structures; they can also be used in aerial archaeology by generating thermal ‘shadows’ of features below ground. Mid-wave infrared (MWIR) cameras meanwhile are growing in use, in defence missions where their higher thermal sensitivity than LWIR cameras helps give military forces an advantage over their enemies in spotting distances for ISTAR (intelligence, surveillance, target acquisition and reconnaissance). They can also be used to monitor chemicals facilities for leaks, as that creates pressure differentials and in turn temperature differentials that can be seen in the mid-wavelengths (3-8 µm). Multi-role sensors In today’s uncrewed systems market, a single IR sensor is increasingly expected to be used across different missions and applications, often as part of a multi-sensor gimbal or a nadir or obliqueoriented enclosure. It will typically be integrated alongside an EO camera, IR cameras sensitive to other parts of the spectrum, or other devices including laser rangefinders, acoustic measuring instruments and illuminators. Military integrators for instance now generally demand multi-role EO/IR gimbals for assessing the condition of strategic assets such as bases or ships, search & rescue operations, or day and Rory Jackson investigates the factors driving developments in thermal cameras and the advances suppliers are making with the technology Combined missions December/January 2024 | Uncrewed Systems Technology Thermal cameras have become a mainstay of UAV surveys, particularly for revealing hotspots, cracks or points of stress in critical infrastructure (Courtesy of Workswell)
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