Nano drones: the future in the battlefields

Although small drones – helicopters and multirotor – are commercially available for several years, they have yet to find their right place in the military.

Limited payload weight and endurance, unreliable communications – particularly over the extended range or in urban terrain, and environment congested electronic interference and limited power on board, are all limiting factors for the military use of commercial systems.

 Some small multirotor drones are designed specifically for military purposes, in fact by 2018 thay should be as part of a new Army program to deploy “Soldier Borne Sensors” to the battlefield.

These sensors will come in the form of tiny pocket-sized drones that can be deployed in seconds to survey the surrounding area.

After seeing the success enjoyed by both British and Norwegian forces with pocket drones, the US military has asked military contractors to start working on an American equivalent.

The British and Norwegians both use the PD-100 Black Hornet (seen above), a 16-gram camera-equipped drone with simple controls that can be learned in as little as 20 minutes.

They allow soldiers to see what’s going on around them without putting them in harm’s way. Some US special operations teams have used the Black Hornet, but the US military has a whole laundry list of specifications for its bespoke nano-drone.

The Maneuver Center of Excellence at Fort Benning,

Georgia has taken into account the performance of the Black Hornet, and designed its proposed specs to be more capable.

The entire drone and control package should weigh less than 150 grams, about the same as a smartphone.

The military also wants it to be deployable within 60 seconds and fly for 15 minutes on a single charge.

It also needs to work at distances of up to 1.2km with line of sight and in winds up to 15 knots.

The drone is no use without a camera, so the military wants a good one that can identify a human-sized object from 50 to 75 feet away.

One other example is the InstantEye Mk2 Gen3 developed by U.S. based company Physical Science Inc. (PSI.)

This folding quadrotor vehicle is deployed in seconds, on missions that can be operator controlled or autonomous.

InstantEye features three cameras – forward, angled, and downward, with multiple zoom levels.

The center crosshairs provide the GPS location of the viewpoint when looking at the ground or the vehicle’s location when looking forward.

Weighing 320 grams InstantEye can carry payloads of 450 g (with the 2Ah battery, or up to 300 grams with the 4 Ah battery that extends mission endurance beyond 30 minutes). Among the additional payloads, it can carry are infrared LED floodlight, GoPro HD or FLIR thermal cameras.

The drone has an effective range of 600-1400 meters depending on terrain, with endurance exceeding 30 minutes.

The ground control station uses the same batteries the drone uses and can run for two hours after a 30-minute recharge.

U.S. Marine Lance Cpl. Benjamin Cartwright, an infantry Marine with Kilo Company, 3rd Battalion 5th Marine Regiment, launches the Instant Eye MK-2 Gen 3 unmanned aerial system during an exercise for Marine Corps Warfighting Laboratory’s Marine Air-Ground Task Force Integrated Experiment at Camp Pendleton, CA. (U.S. Marine Corps photo by Pfc. Rhita Daniel)

One of the development goals for PSI is to allow the drone to fly indoor, perform its mission and avoid obstacles.

A dedicated payload for this capability will use multiple sonars and a wide angle forward-looking camera to detect large obstacles and avoid them – walls, furniture, and people.

Downward and upward sonar maintain a safe vertical distance from the floor and ceiling and enable precise ranging for the monocular optical odometry.

As sonar and vision can’t detect all obstacles, with 100% accuracy, all the time, the drone has to be prepared to survive collisions with objects (such as twigs, windows, or fast moving obstacles) and continue its mission.

For this purpose, propeller shrouds are employed.

A folded InstantEye bot can be stowed in a pouch and is unfolded into a ready-to-fly drone in 10 seconds. Photo: PSI.

PSI’s is also developing an indoor payload that will enable a swarm of InstantEye vehicles to enter, map, and return to the user – all without user intervention.

Using Simultaneous Localization and Mapping (SLAM) algorithms these drones will allow warfighters to conduct autonomous mapping missions without line of site and radio link.

This work is sponsored by the Office of the U.S. Secretary of Defense in conjunction with the Air Force Research Labs out of Eglin Air Force Base. Algorithms were designed in simulation, validated on existing hardware, and are currently being implemented into the InstantEye framework.

PSI is currently designing a lighter and smaller version of the InstantEye, which uses folding arms to reduce stowage size.

Unfolding the drone will take about 10 seconds. A smaller InstantEye is also in the making, with a vehicle weight of about 120 grams, stow in the size of a cargo pocket, and be aurally undetectable 50 feet away.