Air Defense: The Little Things That Matter


December 3, 2019: In Thailand the navy has ordered $4.4 million worth of AUD (Anti UAV Defense) systems from Israel. This particular AUD system from Skylock Systems uses multiple sensors and EW (Electronic Warfare) equipment, plus a short-range laser, to detect, identify and jam or take over unidentified UAVs (Unmanned Aerial Vehicles) trying to enter one of the seven Thai naval bases. The Skylock AUD uses a combination of radar, electro-optical (visual) and electronic signal monitoring sensors to detect the smallest UAVs, especially quad-copters, approaching a base. There is also an interceptor UAV that can drop a net on a UAV but the preferred method is to jam the UAV control signals or, if possible, seize control and land it.

The most widely used AUD for quad-copters is the AeroScope UAV detector. AeroScope is made by DJI, the Chinese firm that builds most of the quadcopters on the market. DJI includes a microchip in its quadcopters that contains information about the quadcopter operator in the control signal. AeroScope is a briefcase-size device that uses two small antennae to monitor for the presence of a DJI control signal within five kilometers. If a control signal is detected the Aeroscope display shows the AeroScope operator data about the DJI quadcopter including location, altitude, speed, direction, takeoff location, operator location, and an identifier such as a registration or serial number.

There have already been instances where Aeroscope has proved inadequate because the target UAV was either not a DJI model or was one that had been altered. Such alterations are not easy to do but possible by someone familiar with drone control hardware and software.

A growing number of AUDs are built to deal with any small UAV. One of the more effective, and expensive of these AUDs is the Israeli Drone Dome system. These cost $3.4 million each and consist of a 360 degree radar system, an electro-optical day/night surveillance unit and a wideband (most frequencies drones use) detector. With all this Drone Dome can reliably detect any small quadcopter or fixed-wing UAV within 3,500 meters. Most quadcopters and UAVs encountered are larger and these can be detected out to ten kilometers. Once spotted Drone Dome can use a focused jamming signal that will disrupt any radio control signals and force the drone to crash or operate erratically. Drone Dome has an optional laser gun that can be aimed by Drone Dome to destroy the drone at ranges up to 2,000 meters. In a combat zone, you can also employ machine-guns to bring down the drone. Many buyers do not purchase the laser option and depend on Drone Dome being able to reliably detect all manner of small quadcopters from several manufacturers.

What makes Skylock and Drone Dome different is their heavy use of electronic sensors to detect and jam the control signals used by UAVs, leaving the laser as a last resort. Several such AUD systems are already in service and effective because they are good at detecting UAVss electronically and either jamming those control signals or taking over the control signals and capturing (by making it land) the UAV. Troops in Iraq and Syria were asking for AUD systems that used lasers and better UAV detection systems as well those with jammers to disable UAVs. There is a need for AUDs that can detect and destroy UAVs that do not use control signals and basically go on pre-programmed missions. This can be to take photos or deliver a small explosive. Usually, it is to take photos and return. Drone Dome is one of several AUD systems equipped to detect and locate UAVs operating in pre-programmed mode and destroy or disable them quietly with a vehicle-mounted laser.

AUDs similar to Drone Dome also use one or more radar systems and one or more sensor systems for detecting UAV control signals or visual images (that pattern recognition software can quickly identify what it is). While commercial UAVs are more common the basic design principles have not changed. AUDs are constantly evolving to better detect and disable or destroy unwanted UAVs. The best ones are recent models that tend to be very expensive and used only for extreme situations, like UAV defense in combat zones. Airports, especially the large ones are going to have to join the military in buying the latest AUDs, which at least lowers the AUD price and inspires even faster innovation and development.

Thailand also depends on Israeli firms to supply most of their military UAV needs. In early 2018 Thailand received four Israeli Hermès 450 UAVs. These were ordered in 2017 as part of a deal that cost $30 million and included training, tech support and some high-end sensors. Thailand has been using Israeli UAVs since the 1990s when Searcher UAVs were ordered specifically for border patrol. These were eventually retired and replaced by Searcher 2 and Aerostar UAVs. Searcher 2s were ordered about a decade after the first Searcher 1s. The new model entered service in the late 1990s and was basically an upgrade of the original Searcher. Searcher 2 is a half-ton aircraft with an endurance of 20 hours, max altitude of 7,500 meters (23,000 feet), and can operate up to 300 kilometers from the operator. It can carry a 120 kg (264 pound) payload.

In 2008 an Aerostar TUAV (Tactical Unmanned Aerial Vehicle), similar to Searcher, was purchased for evaluation. This is a 210 kg (460 pound) aircraft that has a 50 kg (110 pound) payload, and endurance of up to twelve hours. It can operate up to 200 kilometers from the operator, and at altitudes of up to 5,800 meters (18,000 feet). More Aerostars were ordered over the next few years. Thailand was an early adopter of UAVs, buying and operating some early British models in the 1980s. Then Thailand became aware of what pioneering work Israel was doing with UAVs and has been using Israeli UAVs ever since.

Thailand also buys UAVs from other nations; at the same time the Skylock AUDs were being ordered the navy ordered several Austrian Camcopter S-100 helicopter UAVs for use on new frigates. The S-100 weighs 200 kg (440 pounds), can stay aloft six hours per sortie, and operates at a max altitude of 5,500 meters (18,000 feet). Max speed is 220 kilometers an hour. U.S. firm Boeing markets the S-100 in many parts of the world. The S-100 has been operating from warships since 2012 and a growing number of navies have adopted it.




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