Tiny Drones Win Over Army Grunts; Big Bots? Not So Much

by Sydney J. Freedberg Jr. 

A soldier holds a PD-100 mini-drone during the PACMAN-I experiment in Hawaii.

Tiny drones, no bigger than your palm, were the big stars of an Army experiment in Hawaii, participants told Breaking Defense. Larger groundrobots, however, struggled in the jungle.

Staff Sergeant James Roe told me he was “blown away” by the PD-100 Black Hornet, a commercially available mini-drone used in PACMAN-I (Pacific Manned-Unmanned Initiative, part of the Pacific Pathways exercises). “That was a system that we could actually take right now…on the battlefield,” Roe said. “Some of these other systems, as with any electronics and robotics, there are some things that have to be worked out.”

Army Secretary Eric Fanning checks out a robot at PACMAN-I.

Ground robots got particularly mixed reviews. They helped haul equipment for the chronically overloaded infantry, and some could even fire a remote-controlled machinegun, but the tracked ‘bots couldn’t keep up with foot troops over rough terrain.

“There are numerous places, at least on this island, where that SMET (Squad Multipurpose Equipment Transport) cannot go,” said Broc Garner, like Roe a staff sergeant in Bravo Company, 2/27 Infantry. In a mission over rough ground, said Garner, “at a certain point, we’re going to have to either abandon this machine …. or leave two people with it” on guard.

That’s manpower a platoon can’t spare. Indeed, just dedicating troops to operate the remote-controlled machines was a big burden on the small units, Garner said.

A soldier guides a Punisher unmanned ground vehicle during PACMAN-I in Hawaii.

The Army’s tactical radio network also needed boosting. One senior Army scientist involved, Lonnie Freiburger, explained the robots didn’t useregular Army radios “as they do not provide the necessary bandwidth.” Instead, he said, they used a 4G LTE cellular phone network. That’s a reasonable expedient for an experiment, but not something to rely on in combat, when the enemy can listen in or simply blow up cell towers.

The experiment also tested relays to boost signals so they could penetrate the thick foliage, said Freiburger, who works for Tank-Automotive Research & Development Command (TARDEC). One approach was a mini-drone hovering in place. Another was a “canopy buoy” dropped from a helicopter into the jungle canopy.

Ad hoc as it was, the experiment’s network workarounds worked. Neither Garner nor Roe complained about communications. Instead, they exulted in the ability to see video feeds of what awaited their troops in the next village or down the trail, and in the ability to share that video with their superiors.

“The situational awareness tools that we had up there are the ones we’re definitely looking forward to obtaining” as regular issue, Garner said. In current operations, he explained, “the hardest thing to do (is) get that positive identification of a weapon or of hostile intent” so you are cleared to fire. The ability to share video makes that process much faster and easier – without having to put soldiers in harm’s way to check out the target.

A PD-100 in a soldier’s hand, showing the front camera.

American commanders have enjoyed drone video for years, but unmanned aircraft are in high demand and rarely available to frontline soldiers. Besides, an infantry squad can hardly carry around a one-ton Predator or even a 460-lb Shadow. But then again, just needs to see over the next hill.

Enter the PD-100, with a maximum range of a mile-and-a-half and a weight of less than an ounce. “It’s a little smaller…than your palm, it’s 18.25 grams,” said Roe. “It’s very easy for me to set it up, it takes probably three to five minutes for me to have it up in the air.”

The PD-100’s small size also makes it hard for the enemy to see or hear, so it can scout ahead of a surprise attack without giving the game away. Unlike the quad-copters you can buy at Wal-Mart, “there’s no sound. You wouldn’t even know it’s flying over you,” Roe said. “It looks like a bird….The enemy’s not going to know.”

One shortfall is the mini-drone’s tiny body doesn’t have much room for batteries: It can only fly for 25 minutes without needing to recharge. So each squad was issued two PD-100s with a backpack charger, as well as the remote controls. You fly one drone while the other’s charging, then switch them, for what Army science advisor Drew Downing called “almost constant eyes on target.”

How long does the charger last? “We ran it up to three-and-a-half hours, literally leapfrogging birds the entire time,” Garner said. It’ll drain faster if you turn the handheld display to full brightness or if you fly in bad weather – the drone can manage winds up to 40 knots (46 mph).

Once the charging station runs dry, you can recharge it from the ground robots, which had hybrid engines (like a Prius) which could act as mobile generators. For modern soldiers as likely to be overburdened by spare batteries as by ammunition, that’s a big plus.

A soldier mans a robot-carried machinegun during PACMAN-I.

Garner and Roe also appreciated the robots’ ability to mount sensors and haul equipment, particularly a .50 caliber heavy machinegun, the kind of firepower foot troops simply can’t carry. Some of the larger robots were even rigged with a remote-controlled gun mount. Operators are safely hidden in cover, send them towards the enemy and then open fire.

Until the remote broke, which happened to Garner’s unit twice. The fallback was to have a soldier fire the machinegun manually. But then the gunner’s only cover was the robot’s chassis, leaving him largely exposed while making a lot of noise, the kind of target the enemy is bound to notice.

The remote control “worked at the beginning, but by the end, yes, we did just have to place a guy behind that 50 cal,” said Garner. “He definitely gets left out in the open.”

A more reliable remote shouldn’t be too hard a fix but the mobility limitations are much harder to resolve. A vehicle simply can’t climb, jump, or wade like a human soldier. Tanks overcome this problem by brute force, crushing obstacles or smashing them aside. A smaller tracked robot lacks the height and mass.

Garner suggested the ground robots would prove most useful in cities, where they can drive on flat surfaces. “I do think it’s a good system,” he said. “It’ll be an asset in an urban environment.”