By Paul Burton

BOSTON (CBS) – Drones will be hovering overhead of this year’s start line at the Boston Marathon as a new level of security for runners and spectators.

The goal is to scan the crowds and detect threats with some of the most agile technology available.

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With 30,000 runners and one million spectators from Hopkinton to Boylston Street, the iconic Boston Marathon is a sight to behold. But in many ways, the race begins at the Massachusetts Emergency Management Agency bunker where security plans are well underway.

“Just the scale of the operation is so much larger that the exercises themselves become so much more complex,” said MEMA director Kurt Schwartz.

Drone called PARC will fly over Boston Marathon (WBZ-TV)

One of the biggest changes this year to enhance security is having an extra set of eyes from the skies.

For the first time, MEMA will be using a Persistent Aerial Reconnaissance Communications drone called PARC.

“In a scenario like at a marathon, which we’ve been at marathons before where the public safety folks need to keep an eye on the overall view of a large crowd of people,” said Perry Stoll of Cyphy Works.

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Stoll said the state of the art PARC drone can remain in the air for the entire marathon.

“So it gives them a view that they don’t get in any other way, to be able to be up at 400 feet,” said Stoll.

The drone is controlled by a computer and flies itself. The device is tethered to a power box that provides power and communication feeding back real time video to the people on the ground.

Drone called PARC will fly over Boston Marathon (WBZ-TV)

There will be two PARC drones for the marathon, one on Ash Street and the other at Athletes’ Village to provide extra layer of security.

Since the traumatic day on Boylston Street four years ago, things have changed perspective plans and protocols.

The drone is able to see about a mile and a half out and can zoom in to a moving target while following it.

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The drone will provide additional security to the 8,000 MEMA personnel, 10,000 Boston Athletic Association volunteers and thousands of state police troopers.

Paul Burton