Conceptual study of the next-generation compact infrared camera

Abstract

New concepts of compact Thermal Infrared (TIR) cameras were studied as the successor to the Compact Infrared Camera (CIRC) onboard the ALOS-2 satellite launched in 2014. The CIRC, mounting an uncooled bolometer array and weighing only 3 kg, has accomplished eight-year high-resolution (GSD~200 m) TIR earth observations, mainly monitoring active volcanos and wildfires. The next-generation compact camera should have similar size, weight, and power consumption (SWaP) performances to CIRC. Ground resolutions of 30 m to 50 m or below should be needed to understand temperature distributions for crop fields or to measure temperatures for narrow waters and fish farms in Japan. Uncooled bolometer cameras could not gain high MTF from earth-centered platforms to achieve that spatial resolution because of their sizeable thermal time constants. We are choosing cooled detector arrays that are sensitive in mid-wavelength infrared (MWIR, 3 μm to 5 μm). One of the technical advantages of MWIR wavelength is that optics will be much smaller than for longer wavelengths. We are studying the conceptual design of a compact camera that mounts the cooled Type-II Superlattice (T2SL) detector array, which JAXA has developed.