From Gengis Khan and his Mongol commanders to jihadis hiding in the Afghan mountains, fighters have always gravitated towards elevated vantage points to better prepare for incoming enemies. Technology has changed the face of warfare but the benefits of holding the higher ground remain the same, even if it's a flying robot doing the legwork for you. Looking to further boost to its surveillance capabilities, the US military has begun testing a tethered drone system that hovers in the air and streams continuous aerial views to troops on the ground.

Dubbed Tether Eye, the wired aircraft was developed by AeroVironment as a way of offering the military a 24-hours-a-day surveillance tool. It can be launched from fixed locations or while on the move from a portable self-contained base station, which constantly shuttles power to the craft through a ruggedized tether.

Equipped with electro-optical and infrared cameras, it can fly to an altitude of 150 ft (45 m) and capture night and day 360-degree video, which is streamed back to the base station to give troops an all-seeing eye in the sky.

Amid all the hype about regular drones, we have seen the potential of a tethered variety explored before. Russian startup Fotokite's tethered drones have been used by BBC and National Geographic for aerial photography.

And while not a drone per se, the US Navy has tested out an automated parafoil system designed to give its vessels improved situational awareness. Bringing the technology onto dry land in the field of battle, however, could mean an entirely new kind of tactical vantage.

"Having the ability to deploy a 'virtual observation tower' at a moment's notice above buildings and vehicles represents a game-changing capability for intelligence, surveillance, reconnaissance and security operations that has the potential to save lives," says Amanda Toman, Program Manager at the US Combatting Terrorism Technical Support Office. "We look forward to continuing our evaluation of Tether Eye's capabilities with AeroVironment as a possible deployable capability across government facilities."

You can see the Tether Eye in action in the video below.

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