Comparison of plane-to-sky contrast and detection range performance in the visible, short-wave infrared, mid-wave infrared, and long-wave infrared bands

Abstract

Recent advances in uncrewed aerial vehicle (UAV) technology have the potential to benefit diverse civil, commercial, scientific, and defense projects. Many applications would benefit from beyond visual line-of-sight (BVLOS) operations. Such operations require automated safety systems that allow uncrewed aircraft to avoid collisions with both crewed and uncrewed aircraft. Electro-optical and infrared (EO/IR) sensors are commonly employed by aircraft collision avoidance systems. This study compares plane-to-sky contrast in the VIS (0.4 to 0.7 µm), SWIR (1 to 1.7 µm), MWIR (3 to 5 µm), and LWIR (8 to 14 µm) to determine which band is most sensitive to an aircraft signal against a clear sky background. Contrast in the two reflective bands (VIS and SWIR) is determined in terms of equivalent reflectivity, and contrast in the two emissive bands (MWIR and LWIR) is determined in terms of equivalent blackbody temperature. Sensitivity data are then used alongside resolution specifications to estimate the detection performance at-range using the night vision integrated performance model (NVIPM). The results are extrapolated to a maritime atmosphere using MODTRAN. An analysis of the range performance and recommendations on band selection are provided for reference in the design of EO/IR systems for aircraft collision avoidance. Future research may study the band performance at night and against other backgrounds (e.g. clouds, ocean, ground terrain).