Neutralising incoming drones, especially when they operate in swarms, is an issue that most land and naval forces are giving a high priority considering the lessons learned from Ukraine. While the overall the C-UAS solution is universally considered a layered system, in the short-range lasers have a place on their own. At Eurosatory Esh-Tech of Israel will unveil its DroneLight, a system based on a pulsed-laser which guarantees lower energy consumption, improved performances and reduced acquisition cost
Established three and half years ago, Esh-Tech was founded with the clear aim to develop an affordable and efficient laser effector to be used against drones. Since inception the idea was to develop a system based on the pulse-laser technology, which allows concentrating high power in very short time. Instead of heating up the target as a continuous wave (CW) laser does, the DroneLight generates a very high-power pulse that drills a hole in the target, physically removing material. The pulse lasts only 10 milliseconds, the system emitting at a 5 Hz pulse repetition frequency (PRF). “Last year we made several tests,” Erez Riahi, CEO and co-founder of Esh-Tech told EDR On-Line, “and we saw that to kill a drone we needed to drill between 5 and 10 holes into the target,” he added. It is a statistical result, as with those numbers of holes the probability to destroy a vital element of the drone, battery, electronics, camera, is nearly 100%. The results were obtained on over 20 drones and, considering the 5 Hz PRF, the DroneLight needs between one and two seconds to down a UAV.
Esh-Tech aimed at providing a tactical system, capable to generate a safety bubble of around 1 km radius, which is the range of its DroneLight.
As it emits for only 50 milliseconds every second, this means the laser is active only 5% of the engagement time, power consumption being therefore pretty limited; according to data provided by Esh-Tech compared to the over 20 kW needed by a conventional CW laser emitter which needs to remain aimed on the target for a much longer time, the DroneLight energy consumption is around 4 kW. The reduced time-on-target needed by this pulse-laser system has other beneficial effects; on one hand, tracking and stabilisation become similar to those needed by a conventional high-tier remotely controlled weapon station, angular speed in azimuth and elevation being 120 °/s while acceleration is 60°/s2, on the other it allows to kill a higher number of targets in a very short time. Considering a kill time between 1 and 2 seconds, the DroneLight should be able to down around 30 enemy drones in one-minute, other systems being capable to kill less than 10 according to Esh-Tech. The other good thing is that the small 4 kWh battery currently adopted for the system ensures a one-minute continuous work, however this is either reloaded by the platform power system or linked to the grid in case of use in a static position. Of course, bigger batteries can be installed.
Pulse laser technology does not allow using fibre optics due to the high power involved. The DroneLight tracking system and laser emitter exploit the same 300 mm diameter optical aperture, which means they are inherently boresighted, and the laser does not have any moving part, increasing reliability especially when installed on a vehicle. “We invested a lot of engineering effort to make the optical and laser elements operating through the same optical path, and I think we are the first one in the world to adopt this technology,” Erez Riahi told us. The pulse technology does not generate the same amount of heat produced by a CW laser, which makes the cooling system smaller, cooling being mostly required to optimise laser performance.
Aiming at maximising its new system performances, Esh-Tech worked on monitoring the atmosphere between the emitter and the target; this is done using the camera which picture is refreshed 1,000 times per second, the image being analysed by AI-driven algorithms that establish when the laser should emit to get the best performance. Within one second the laser is “fired” five times; therefore, the system plays with intervals to optimise the result in terms of energy delivered on target. “The difference can be dramatic between a good window atmosphere and a poor one; while the pulse duration remains constant, 10 thousand of a second, we can wait up to 50-60 milliseconds before emitting the second pulse to send it when the atmosphere is more favourable, and this can improve the performance up to 50% and even more, the company CEO explains, adding that related algorithms are being improved over time.
While not being as big as other solutions, the DroneLight is not a manportable system. The optical head has a mass of around 450 kg, is 1.5 metres tall and less than 1 metre wide, while the “black box” containing ancillary elements has a mass of around 350 kg and can be fitted inside the platform.
The DroneLight can be linked to any type of sensor, radar, acoustic, optronic, which would cue it towards the target. At Eurosatory the system was visible at the company booth as well as at the ** FFG ?? stand, installed over an armoured tracked vehicle.
The system is considered TRL8, close to make one further step forward; “we will soon deploy our first system, which should be operational in September this year,” Erez Riahi said, adding that Esh-Tech already bagged orders from several customers around the world. The company is looking not only at the land market but is also actively considering the naval one. Beside performances, affordability is the other key driver, the DroneLight cost being estimated at around 25% that of conventional CW laser effectors.
