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.
A novel, low-cost, camera-based method of detecting a single nanosecond laser pulse and kHz modulated continuous wave and pulsed lasers has been developed at DSTL. The detector uses a simple optical modification to a standard rolling shutter colour camera combined with image processing techniques to distinguish lasers from other illumination sources and extract a lasers wavelength and pulse repetition frequency. In addition the detector is also capable of detecting a single nanosecond laser pulse at any given time. Such a detector has applications in free-space optical communications, as a low cost broadband method of extracting information from multiple sources, and as a detector of laser range finders. A low cost prototype (≈£600) has been developed using entirely off-the-shelf components and assessed in laboratory conditions, with the ability to measure laser wavelengths to ±5nm and pulse repetition frequencies to within ±5%. In the laboratory the prototype was also able to detect each of the 1000 pulses generated by a 10Hz 10ns 532nm pulsed laser, as well as 100 pulses sent at random intervals, highlighting its capability to detect a ns pulse at any given time. The prototype was taken to the Moonraker NATO SET-249 field trial, where it was able to measure the pulse repetition frequency of a modulated continuous wave laser source to within ±5% at a distance of 660m. This novel technology offers a low cost method of detecting lasers and extracting their pulse repetition frequencies, with a wide field of view and high spatial resolution.
A novel, low-cost, camera-based method of detecting Continuous Wave (CW) lasers has been developed at DSTL. The detector uses a simple optical modification to a standard colour camera combined with image processing techniques to distinguish lasers from other illumination sources, as well as measuring the wavelength, direction and irradiance of the laser light. Such a detector has applications in collecting information on aircraft laser dazzle incidents: providing the evidence required to inform on aircrew laser exposure events and to assess if engagements are eye safe. A prototype has been developed using entirely Commercially available Off-The-Shelf (COTS) components, costing ≈£600, and assessed in the laboratory conditions, with the capability of measuring laser wavelengths to ±5nm and irradiances to ±10%. A realistic hand-held laser engagement scenario, using a range of relevant wavelengths and irradiances, was simulated during the Moonraker trial where the prototype was capable of measuring laser wavelengths to an accuracy of ±10nm, and peak irradiances to ±25%. Comparisons were made with a COTS laser detector, and showed an equivalent performance. This technology offers a low cost approach to CW laser detection, which is capable of extracting a range of parameters, whilst maintaining a relatively wide Field of View (FOV) and angular resolution.