Britain had something of an aviation crisis in late 2018 when someone allegedly flew a quadcopter near the runway of Gatwick airport near London and did so several times. Over a hundred people, including police and airport pilots, spotted the quadcopter between December 19 and 21. Some quadcopter sighting near airports turn out to be a plastic bag being blown about but this one was apparently the real deal. Initial efforts to deal with the situation failed and over 140,000 passengers had their flights delayed or canceled. The ultimate cost of the mystery (they were never identified) quadcopter operator was over $66 million.
The airport initially brought in an inexpensive and widely used 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.
The Gatwick quadcopter was either not a DJI model or was one that had been altered (not easy to do but possible by someone familiar with drone control hardware and software). The military was consulted and they brought in one of their recently acquired (a few months earlier) Drone Dome systems. 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 (Unmanned Aerial Vehicles) 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. The British military did not purchase the laser option but was able to reliably detect all manner of small quadcopters from several manufacturers during tests earlier in 2019. It was not revealed if Drone Dome detected anything at Gatwick but the drone sightings stopped and Gatwick has since brought in a similar system to be permanently available for illegal drones operating around the airport.
The same Israeli firm (Rafael) that developed the Iron Dome system (for effectively and economically destroying rockets and shells from mortar and artillery) in 2005 had, by 2017, developed a version optimized to detect and shoot down small UAVs. Drone Dome is a lot cheaper because it does not use $90,000 Tamir guided missiles to intercept rockets or shells headed for residential areas or military targets. Instead, Drone Dome uses a high powered laser that can destroy or disable most UAVs. Drone Dome uses a radar that can detect most small UAVs at ranges of up to 30 kilometers at altitudes of 10 meters (30 feet) to 10,000 meters. Drone Dome is not a radical development but part of a trend. Since 2010 Israeli firms have developed a growing number of AUD (Anti UAV Defense) systems largely because Israel is a nation that is most often threatened by hostile use of UAVs, particularly small commercial ones increasingly used by Islamic terrorists and criminal gangs.
What makes Drone Dome different is its heavy use of electronic sensors to detect and jam the control signals used by UAVs, leaving the laser as a last resort. Several 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 is buying the latest AUDs, which at least lowers the AUD price and inspires even faster innovation and development.