In August 2016, Bloomberg Businessweek revealed the existence of a pilot program being operated by the Baltimore Police Department in which small manned aircraft circled over the city all day, using cameras to continuously photograph a 32-square-mile area and giving police the ability to retroactively track any vehicle or pedestrian within that area. It was the ultimate Big Brother "eye in the sky"—and yet the Baltimore police had not notified the public or even the mayor or city council about the program. Revelation of the secret program generated a storm of controversy, and eventually it was put on hold—though in December 2019, the city's police commissioner announced that the program would be revived.
The technology behind the Baltimore program involves pointing multiple cameras toward the ground and stitching those images together into a single, larger photograph. It also uses computers to automatically correct for the changing camera angles of the circling planes as well as factors such as topographic variances and lens distortion.
The result is a surveillance system of enormous power, able to reconstruct the movements of all visible vehicles and pedestrians across a city—where they start and finish each journey and the paths they take in between. It can allow tracking of a great proportion of people's movements throughout a city.
The Baltimore program and brief tests in other cities have been run by a private firm called Persistent Surveillance Systems (PSS). The company's surveillance is usually carried out using manned aircraft. But if Americans decide to allow this kind of ongoing aerial surveillance over their communities, drones will almost certainly replace manned aircraft, if and when the Federal Aviation Administration (FAA) permits the kind of flights involved.
Drones, or unmanned aerial vehicles (UAVs), have become an increasingly common presence in the past decade. Their integration into daily life is poised to reach a new level as their technological capabilities and legal latitude for operation expand. That increased presence will likely bring certain conveniences and efficiencies but will also make drones an increasingly powerful tool for surveillance. As that happens, drones will become a tool of growing interest to local, state, and federal law enforcement—and the importance of understanding just what the capabilities of these machines are will likewise grow.
Drones themselves are not capable of any surveillance. They are a platform on which operators can attach surveillance equipment. The only limits are the types of tools that have been invented, how practical they are for use in the air, and their size and weight. Among the equipment that can be attached to drones are GPS, radar, lidar, rangefinders, magnetic field change sensors, sonar, radio frequency sensors, chemical and biochemical sensors, and, of course, cameras. Many cameras include thermal and other sensors that collect signals beyond the visual part of the electromagnetic spectrum.
Drones could also be used to carry equipment for electronic signals collection. For example, law enforcement has in the past decade begun using devices known as cell-site simulators (popularly known as "Stingrays") that are essentially fake cellphone towers. Like real towers, they broadcast a signal that prompts any mobile phone in range to identify itself to the device. They can thus be used to collect the identities of people in a particular area en masse. The FBI, the U.S. Marshals Service, and other law enforcement agencies have acknowledged that they sometimes use an aerial version of these devices, known informally as "dirtboxes," on manned aircraft. We don't know of any deployments on drones, but as extended drone flights become increasingly possible, such deployments are very likely.
In July 2016, a gunman opened fire at police officers in Dallas, Texas, killing five and wounding seven others. The shooter was cornered in a parking garage, and when negotiations "broke down" after a number of hours, police said, the department repurposed a bomb-defusing ground robot with an explosive charge and drove it near the gunman before detonating the charge, killing the gunman. The incident kicked off a national discussion about police using "killer robots." Under a 1985 Supreme Court case, Tennessee v. Garner, as well as other cases, the police may not constitutionally use deadly force unless someone represents an imminent threat to others and the use of lethal force is a reasonable last resort.
While lethal drones have been deployed for years by the military overseas, efforts to arm domestic drones are widely (and wisely) seen as beyond the pale, and for the most part lawmakers and law enforcement officials have not yet seriously contemplated using armed drones within the United States. The International Association of Chiefs of Police has recommended against arming UAVs. Nevertheless, there's no question that drones have the potential to serve as a platform for weapons.
There are exceptions to the general taboo against arming drones. One sheriff in Texas mused about mounting less-lethal weapons such as rubber bullets on drones. The Electronic Frontier Foundation uncovered documents from U.S. Customs and Border Protection (CBP) suggesting possible future enhancements to its drone program, including "non-lethal weapons designed to immobilize" targets of interest, although CBP denied any plans to arm its drones with "weapons of any kind." And in 2015, North Dakota enacted a drone bill that explicitly permitted law enforcement to equip drones with less-lethal weapons such as rubber bullets and tear gas.
Arming drones is something that is entirely feasible as their overseas use makes clear. There is good reason to think that at some point, if and when drones become a common part of everyday life, we will see weapons deployed via UAVs closer to home as well.
Drones at the Border
The most prominent and consistent domestic use of drones by a federal government agency is CBP's use of drones at the nation's borders. The agency began flying drones along the southwestern border in 2006 and has since expanded its deployments to the Canadian border, the Caribbean, the Gulf of Mexico, and the southern California coast. Since 2011, the craft have been operated from three National Air Security Operations Centers located in Sierra Vista, Arizona; Corpus Christi, Texas; and Grand Forks, North Dakota. In 2017, according to the Department of Homeland Security inspector general, the CBP completed 635 flights from its three operations centers.
CBP uses MQ-9 Predator B ("Reaper") drones, as well as a variant called the "Guardian" for maritime operations. These are large craft, with a wingspan of 66 feet, capable of carrying a payload of 3,850 pounds. They have a claimed ability to fly for up to 27 hours, a maximum speed of 276 miles per hour, and a maximum range of 1,878 miles. Their maximum altitude is 50,000 feet, though the CBP missions fly no higher than 28,000 feet. (They're required by the FAA to remain above 19,000 feet and venture no more than 60 miles from the southern border and 100 miles from the northern.) Each drone is operated by three employees: a pilot, a technician, and a "sensor operator" who monitors the surveillance feeds, zooming in on suspected targets where desired.
These craft carry a range of video, radar, and other sensing technologies. Prominent among them is a system called Vehicle and Dismount Exploitation Radar (VADER). VADER is based on synthetic aperture radar, a technology that simulates a much larger antenna than would otherwise be practical by leveraging the fact that a moving aircraft covers a wide span of space as it moves. It can create much higher-resolution three-dimensional images than conventional beam-scanning radars, and because of advances in electronics, the technology has become increasingly economical for small-scale uses.
Synthetic aperture radar can create high-resolution still images and a "real-time ground moving target indicator" that works "by detecting the Doppler shift that moving objects produce in radar return signals," according to Defense Systems. This, as one CBP official told a reporter, lets analysts see either still images that "look something like high contrast black-and-white photos'' or "moving targets displayed as dots superimposed on a map." One source calls it a "man-hunting radar." VADER is also used for change detection, with resolution that makes it "capable of seeing even small changes to a scene such as tire tracks and footprints."
"We can take a picture, go back and take another picture later of the same thing, and run a computer algorithm to determine what has changed in those two pictures," the CBP official said.
All that said, the value of CBP's Predator program is highly questionable. Repeated reports from the Government Accountability Office (GAO) have found serious problems, including very low actual availability of the aircraft for flight, shorter than advertised flight times, high susceptibility to disruption by clouds and other weather, and crashes. GAO findings suggest that the drones may have detected at most 1.2 percent of illegal border crossings, making them very expensive in proportion to their effectiveness.
A Legal Trojan Horse
When Congress gave CBP the authority to fly drones at the border, it was undoubtedly to safeguard the border. But the agency has made a practice of regularly loaning its Predators to other law enforcement agencies inside the United States for a range of other purposes. These loans effectively turn CBP's border protection program into a legal Trojan horse, allowing entry of large, military-grade drones into American life in a way that was never authorized by the legislative branch.
A records request by the Electronic Frontier Foundation showed that from 2010 to 2012, CBP flew nearly 700 missions for other agencies. Those included immigration agencies; the FBI; the Drug Enforcement Administration; the Bureau of Alcohol, Tobacco, Firearms and Explosives; the U.S. Marshals Service; and state police departments. The purposes ranged far afield from CBP's border patrol mission and included such things as investigating fishing violations and searching for marijuana plants, drug labs, and at least one case of missing cows.
No other federal agencies are using the technology to the same extent as the military and CBP, but there is little doubt that drone use is growing. The FAA has entered into memoranda of understanding with a number of other federal agencies, including Homeland Security, the Department of Justice, the Department of the Interior, and the U.S. Forest Service, to "enable each agency access to certain airspace for public aircraft operations in accordance with applicable laws and government agency policy."
The FAA has expanded other avenues for government use of drones as well. In 2015, the FBI wanted to use a drone to investigate a shooting in Tennessee, but due to a miscommunication with the FAA it was not able to do so. "We realized during that event that there was a gap in the way [unmanned aerial surveillance technologies] were cleared for operation in the National Airspace," an FAA official recounted in 2019. As a result, the FAA created a standing, on-call group with authority to rapidly authorize emergency drone flights outside of the baseline rules. After that, the number of exemptions from normal drone flight rules granted to law enforcement and other officials nearly doubled.
These exceptions, called Special Government Interest authorizations, can be granted for large national events such as the Super Bowl, emergencies such as hurricanes, and law enforcement uses including finding hit-and-run drivers. Drones are also being used increasingly by the U.S. Forest Service and other agencies to fight fires. It's not clear whether any checks and balances are in place to prevent the misuse of the term "emergency," which has been a common government tactic throughout history.
We do know that the FAA has been excessively deferential to law enforcement. In 2014, for example, the FAA approved a no-fly zone over Ferguson, Missouri, during protests there over the police shooting death of black teenager Michael Brown. The 37-square-mile restriction was put in place at the request of police, ostensibly to protect public safety. But documents and audio recordings indicate that the police really just wanted to keep news helicopters from recording their activities—and that FAA officials were aware of this real purpose. In a context where law enforcement was actively working to suppress media coverage of police behavior during the protests, the FAA specifically tailored the restriction to keep out news helicopters while allowing other routine air traffic—a clear violation of the First Amendment.
The FAA also approved questionable flight restrictions over the Dakota Access Pipeline protests in North Dakota in 2016. This period saw significant and troubling law enforcement activity, such as the use of heavily militarized weapons against protesters during an October 2016 raid of the protesters' camp by hundreds of soldiers and police. In a spread-out rural setting where drones allowed reporters to see what police were doing in a way that was not otherwise possible without expensive aircraft, the police shot down or confiscated the drones of several media members.
Eyes to the Future
We don't know how the FBI or other law enforcement agencies may be planning to expand their use of drones to carry out the aerial surveillance they already conduct on a daily basis across the United States.
In November 2019, the DOJ issued an updated internal policy on the use of unmanned aerial surveillance. The policy contains good-sounding language about the importance of privacy and civil liberties, but in addition to lacking the force of law, it's so broad that the extent to which it will actually constrain federal law enforcement remains unclear. For example, it says that in determining how to use aerial sensors, DOJ personnel "will assess the potential intrusiveness and impact on privacy and civil liberties, which will be balanced against the relevant governmental interests." The policy also says that the DOJ "will only use [unmanned aerial surveillance] in connection with properly authorized investigations and activities." None of that language can be counted on to preclude law enforcement from carrying out extended wide-area domestic surveillance.
Interest in government drone use peaked around 2015, as public anticipation over the integration of drones in American life far outpaced reality. Today, with visible drone integration continuing at a slow pace, media attention is much more focused on the potential for drones to be used by hostile actors. The flow of public information about the government's use of drones that's being sought from and released by federal agencies has correspondingly shrunk.
Yet the need for transparency and public discussion over drone technology has never waned. The wheels are in motion for this technology, and the surveillance it enables, to become far more powerful and far more prevalent than it is today.