Cities have become the new battleground and Hybrid or Urban Warfare the greatest threat being waged by ISIS to Boko Haram to Hamas to Ukraine rebels. One of the biggest emerging threat in cities is growth and proliferation of UAVs or drones. In a written statement, Baroness Anelay of St Johns said: ‘The Government has a range of material, including images, that provides evidence that Daesh (ISIS) has used small, commercially available unmanned aerial vehicles in Syria and Iraq to extend their surveillance capability, produce propaganda material and carry small improvised explosive devices.’In DARPATech 2004, DARPA elevated urban warfare to the level of a strategic thrust.
“The Security Impact of Drones: Challenges and Opportunities for the UK” suggests, that commercial drones could be used by gangs to monitor the movement of police, security guards, or anti-smuggling patrols so as to better plot their criminal mischief. Burglars, train robbers, and poachers could use them as lookouts. Larger models might be used to carry smuggled goods; something we’ve already seen in Mexican cartels reportedly flying drugs across the border. Alternatively, they could be weaponized.
And as off-the-shelf UAS become less expensive, easier to fly, and more adaptable for terrorist or military purposes, U.S. forces will increasingly be challenged by the need to quickly detect and identify such craft—especially in urban areas, where sight lines are limited and many objects may be moving at similar speeds, says DARPA. DARPA has launched Aerial Dragnet seeks to perform persistent wide-area surveillance of multiple small unmanned aerial systems (UASs) in urban terrain on a city-wide scale.
AT&T is currently working with NASA to develop an Unmanned Aircraft System Traffic Management program that will enable agencies across the country to monitor drone activity, as reported by Ryan Banister. According to a statement released by AT&T, this program is supposed to assist drone operators in monitoring flight paths and navigating drones as well as using them for surveillance. The company says that its main goal is to protect against cyber attacks on drones.
Drones are difficult to detect and difficult to neutralize
In white House incident, the Radar systems designed to detect flying objects such as airplanes, missiles and larger military drones failed to pick up the small two foot diameter quadcopter drone as it entered the restricted area around the White House. Their low operational altitude along with small size, small RCS and small IR signature of the UAV makes it a difficult target for most of the common air defense systems such as antiaircraft guns and shoulder-fired IR missiles.
“Small UASs are rapidly becoming low-cost aerial platforms for hostile reconnaissance, targeting, and weapon delivery. Unlike traditional air targets, small UASs: 1) fly at low altitudes (e.g., < 400 ft) which make them easily hidden by complex terrain, 2) move at slow speeds (e.g., < 90 kts) which make them difficult to differentiate from other movers, and 3) are small in size (e.g., < 55 lbs.) making them difficult to sense,” says DARPA.
Current counter-UAS approaches either: 1) require line-of-sight (LOS) target viewing geometries not possible in urban terrain, or 2) exploit fragile vulnerabilities of commercial UASs obsoleted by rapid adaption.
“In future urban battlegrounds, U.S. forces will be placed at risk by small UAS which use buildings and naturally-occurring motion of the clutter to make surveillance impractical using current approaches. The rapid proliferation of commercial UAS with increasing endurance and payload capacity drives the need for a future urban aerial surveillance system that can detect, track, and classify many different UAS types at longer ranges in urban terrain,” says DARPA.
DARPA has launched its Aerial Dragnet program that seeks innovative technologies to provide persistent, wide-area surveillance of all UAS operating below 1,000 feet in a large city. While Aerial Dragnet’s focus is on protecting military troops operating in urban settings overseas, the system could ultimately find civilian application to help protect U.S. metropolitan areas from UAS-enabled terrorist threats.
“Commercial websites currently exist that display in real time the tracks of relatively high and fast aircraft—from small general aviation planes to large airliners—all overlaid on geographical maps as they fly around the country and the world,” said Jeff Krolik, DARPA program manager. “We want a similar capability for identifying and tracking slower, low-flying unmanned aerial systems, particularly in urban environments.”
The Aerial Dragnet concept for surveillance of an urban area through a network of tethered platforms and long-endurance UASs each providing coverage of a neighborhood-sized urban area. In order to cover a neighborhood-sized area with a minimum number of platforms, a notional single surveillance node design would provide coverage and support dissemination of a COP to a small number of users over a 20 km2 area. Likewise, a networked city-wide configuration should provide coverage and support dissemination of the COP to a large number of units over a 180 km2 area.
The Aerial Dragnet system will provide a continually updated common operational picture (COP) of the low altitude airspace (i.e., below 1000 ft) where the threat drones shall be flying. The COP will consist of geographically-referenced tracks of all small UASs, labeled as friends or foes, within the coverage area.The required system must perform UAV detection, track initiation, NLOS tracking, and classification of multiple small UASs flying at altitudes between 10 and 1000 feet.
The COP shall be shared with users upon demand by interfacing with existing secure commercial and/or military data links. Networking of the surveillance nodes will provide scalability to a larger network for city-wide coverage as well as providing surge capability and resilience to node outages.
Low Cost COTS sensors
Because of the large market for inexpensive small UAS, the program will focus on combining low cost sensor hardware with software-defined signal processing hosted on existing UAS platforms. The resulting surveillance systems would thus be cost-effectively scalable for larger coverage areas and rapidly upgradable as new, more capable and economical versions of component technologies become available.
Using sensor technologies that can look over and between buildings, the surveillance nodes would maintain UAS tracks even when the craft disappear from sight around corners or behind objects. The tethered platforms and long endurance UAVs shall contain electro-optical (EO) systems, gimbals, and air-to-ground data links for small UASs. Other components, such as signal processing for NLOS detection, radar-quality radio frequency (RF) subsystems, and sensor-driven autonomous behaviors which adapt to urban environments, are not currently available. The Aerial Dragnet program seeks teams with expertise in sensors, signal processing, and networked autonomy to achieve its goal.
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