Unmanned aircraft are getting smaller and cheaper but there are warnings the widespread civilian use of surveillance technology can cause psychological harm.
Spies in the sky spark privacy fears
Drones, unmanned surveillance and search-and-destroy aircraft initially developed by the military are now being deployed for commercial use.
A new generation of small, low-cost drones, otherwise known as unmanned aerial vehicles (UAVs), has been rapidly developed on the back of miniaturised global positioning and camera technology first developed for smartphones.
But while law enforcement agencies around the world are investing billions of dollars in drones, there are fears their growing use poses a major threat to personal privacy.
Police and governments in markets such as the United States, Russia and Europe are this year placing large orders. The drone maker General Atomics, which is based in the US and expected to launch an unarmed version of its Predator drones later this year, regards the Middle East and Latin America as particularly promising markets for the new breed of commercial drones.
In the US, drones have patrolled the border with Mexico for almost two years. The defence department is reported to have last year sent its drones across the border to shadow Mexican drugs traffickers.
Between now and 2020, Russia is expected to spend about US$13 billion (Dh47.75bn) on unmanned aircraft, some of which are to be used to monitor marches and demonstrations. Drones also form a key part of the European Commission's $410 million plan to improve border security.
Last year's industry forecasts predicting the global market for drones would reach $94bn over the next 10 years may turn out be underestimates as they fail to take full account of the rapid deployment of the vast range of unmanned aircraft now generally referred to as "drones".
The largest drone, the Israeli-made Eitan, has a 26-metre wingspan and is about the size of a Boeing 737. By contrast, the hand-launched AeroVironment Raven weighs 1.8kg and has a wingspan of only 1.4 metres.
These latest drones already cost a fraction of the price of conventional aircraft, to an extent a result of advances made in smartphone technology.
Microprocessors developed for the smartphone and computer tablet market by the British chip designer Arm are perfect for small drones due to their low power consumption and compact size.
Smartphones also use inertial sensors and sophisticated satellite-linked global position systems to detect their geographical location together with high-quality miniaturised digital video and stills cameras.
Airborne communication systems costing hundreds of thousands of dollars can now be replaced by chip sets costing less than $20. This new level of miniaturisation is thought to have enabled the Pentagon to develop a tiny drone named the Nano Hummingbird, which is designed for stealth surveillance. It has a wingspan of only 16.5 centimetres and weighs less than a single AA battery.
Civilian researchers at Wright State University in Ohio have even gone one better and produced a "butterfly" prototype with a 12.7cm wingspan and claim to be on the path to making a surveillance drone bigger than a fly.
The fact that the US Federal Aviation Administration is planning to allow the commercial use of drones in 2015 has already alerted citizens rights groups such as the American Civil Liberties Union (Aclu).
A report titled Protecting Privacy From Ariel Surveillance published in December stated: "We need a system of rules to ensure that we can enjoy the benefits of this technology without bringing us a large step closer to a 'surveillance society' in which our every move is monitored, tracked, recorded and scrutinised by the authorities.
"The amazing continual decreases in the prices of electronics that have become normal in our time all but guarantee that the surveillance technologies attached to UAVs will become less expensive and yet more powerful - and with mass production, the aircraft that carry those electronics will become inexpensive enough for a police department to fill the skies over a town with them."
The US air force is already reported to be testing a system called Gorgon Stare using multiple video cameras to simultaneously overlook all the citizens of a town.
A report produced out of the University of California, Los Angeles warns drones can easily be equipped with high-power zoom lenses that increase the chances individuals will come under the close scrutiny of the authorities without even knowing it. Aclu, meanwhile, reports the military is developing radar technologies that can track "human targets" even when they are inside buildings.
According to its report, this widespread use of surveillance drones by law enforcement agencies could cause grave psychological harm. "Psychologists have repeatedly found that people who are being observed tend to behave differently and make different decisions than when they are not being watched."
This effect is so great a recent study found "merely hanging up posters of staring human eyes is enough to significantly change people's behaviour", said the Aclu report.
Nonetheless, the number of drones has begun to grow at an exponential rate as both their cost and size continue to decrease.
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