Micro UAV Detection
MICRO-UAVS ON THE RISE: DETECTION CHALLENGES
Over the past ten years, advanced developments in Unmanned Aerial Vehicles (UAVs) technology have resulted in high levels of autonomy, versatility, and performance with a wide range of applications, either civil or defense-related. These missions include: reconnaissance, surveillance, crop-spraying, weather-related missions, recreational or professional photography, but can also present very real security concerns when put into the wrongs hands: smuggling (of weapons, drugs, cell phones), harassment (by activists or paparazzi), espionage or potentially sabotage and terrorist attacks are a few examples. Hacking also poses a threat if control of a UAV used during a mission is diverted by attackers interested in stealing proprietary data or the drone itself.
By 2020, the Federal Aviation Administration (FAA) expects to have as many as 30,000 drones flying in the United States.
CBS News reports that the top-selling drone - also commonly used for smuggling - can be bought on Amazon for anywhere from $400 to $1,800. CEA’s U.S. Consumer Electronics Sales and Forecast report predicts that UAV sales will reach $130 million in revenue in 2015, 55 percent more than in 2014, with sales expected to reach 400,000 units.
Concerns are quickly rising as recent incidents have demonstrated the inability to detect and track the often cheap, slow-moving, low-profile targets with conventional sensors. Incidents have been numerous; on the border, around critical infrastructures, airports, and prisons around the world.
Paraplanes have been used for years to smuggle drugs over the US Southern Border. They are hard to spot and can carry hundreds of pounds of payload. In 2012, CBP had recorded 223 ultralight incursions along the US-Mexico border. The drugs were unloaded to accomplices in the US who picked them up, while the ultralight returned to Mexico. Flying as low as 200 feet above the ground, ultralights are particularly difficult for radars to detect due to their wings being made of fabric and limited amounts of metal materials being used which significantly reduce the radar cross-section. Recently, drug traffickers are turning to UAVs for smuggling drugs, in order to avoid accidents or being caught. Indeed, the Ultralight Aircraft Smuggling Prevention Act of 2012 increased the penalties for ultralight smuggler pilots: the law closed a loophole where ultralight aircraft in drug smuggling were treated differently than larger aircraft. Now, the penalty can be a 20-year jail sentence and up to $250,000 in fines. Smugglers can also program UAVs to land at a specific location autonomously, which offers them an additional layer of protection. In January 2015, as reported by LA Weekly, a $1,400 drone was used to bring crystal meth over the border and ended up crashing in a parking lot in Tijuana.
Figure 1 - An image of a paraplane being used near the Southern Border.
A recent series of incidents where UAVs were spotted flying above nuclear facilities in France raised the concern of espionage and terrorism. The illegal flights performed at night were initially thought to have been operated by amateurs or pranksters. However, the UAVs that were used were more powerful and complex than the usual recreational drones: they were more expensive, helicopter-like models that can stay airborne for dozens of miles. A more recent incident involving coordinated visits to 5 nuclear reactors hundreds of miles apart escalated the French government’s level of concern. A campaign of harassment by anti-nuclear activists could be the reason for the incidents, but authorities have not excluded possible surveillance flights by terrorists.
Prisons have also seen the rise of UAV threats in recent years, resulting in drugs and cell phones being smuggled over their perimeter fences.
In 2013, four people were accused of trying to fly a DJI Spektrum DX6i hexacopter carrying tobacco and cell phones into Calhoun State Prison, Georgia, as reported by BBC. On April 21, 2014, as reported by ABC News, a crashed drone carrying contraband (marijuana, tobacco, and cell phones), was found in bushes outside the fence of Lee Correctional Institution, a maximum-security prison in South Carolina. Other occurrences were noted in Australia, Brazil, Greece, Switzerland, England, Quebec, and Russia.