NATO SET-249 joint measurement campaign on laser dazzle effects in airborne scenarios

In October 2018, NATO SET-249 performed a common trial at WTD 52, Oberjettenberg, Germany, to study laser dazzle effects in an airborne scenario. The facility is equipped with a cable car and is ideal for slanted path experiments from the base station to the cable car where the sensors were mounted. NATO SET-249's background is laser threat evaluation and the evaluation of the impact of laser eye dazzle on the visual performance of humans. This work gives an overview on the various measurements performed here: 1. Assessment of dazzle effects originating from light scattering at an aircraft canopy by comparing the images of two cameras: one outside and one inside the canopy. The general findings showed that the canopy, which had been used previously on an aircraft, substantially affected the dazzle pattern in the camera within the canopy as compared to the camera outside. 2. Sensor dazzling: Laser dazzling of complementary metal-oxide-semiconductor (CMOS) cameras in the visible domain and, in addition, laser dazzling of a camera equipped with a fisheye lens, which is commonly present in micro-unmanned aerial vehicles, is demonstrated. The dazzled area in the camera field of view (FoV) grows with increasing laser irradiance, and dazzling is effective at irradiance levels around a few μW/cm². 3. An overview on realistic handheld laser engagement scenarios to test the capabilities of a DSTL-developed Laser Event Recorder (LER) is provided. This technology is able to detect continuous wave (CW) and pulsed lasers, and extract their wavelengths, irradiances, Pulse Repetition Frequency (PRF) and directionality. Applications for this LER include collecting information on aircraft laser exposure events, giving information to assess if engagements are eye safe. 4. Measurements performed on various Fraunhofer IOSB developed sensor systems hardened against laser dazzle: The hardening measure of these systems is based either on the use of spatial light modulators or on the implementation of the principle of complementary wavelength bands. The field trial offered the possibility to generate data of the hardened systems under real life conditions.