They came, they flew, they wildly exceeded expectations.
More than 40 Cadets and Midshipmen from the U.S. Military Academy, the U.S. Naval Academy, and the U.S. Air Force Academy helped expand the capabilities of swarms of highly autonomous unmanned aerial vehicles (UAVs) last month in the Service Academies Swarm Challenge. In the skies over Camp Roberts, an Army National Guard post north of Paso Robles, California, each academy demonstrated the innovative offensive and defensive tactics they had developed over the school year. The three-day experiment concluded with an exciting aerial battle in which the Naval Academy took home the win, a trophy, and bragging rights over its rival academies.
“The teams absolutely achieved their goal for this event by demonstrating 25-on-25 mixed swarms of fixed-wing and quad-rotor aircraft conducting swarm-on-swarm battles,” said Timothy Chung, the DARPA program manager leading the research effort. “The Cadets and Midshipmen developed innovative tactics for these highly autonomous swarms and demonstrated those tactics in live-fly experiments. It was a phenomenal success.”
That success was the result of the teams and DARPA alike overcoming numerous obstacles in the eight months leading to the final Live-Fly Competition. In addition to creating viable tactics, the students had to manage their own packed schedules, diverse areas of study, and the complex technology, logistics, and team assignments for the competition itself. In this short period of time, DARPA developed, built, and tested custom communications networks and various real-time data-visualization systems designed to track dozens of UAVs simultaneously.
How it all would work out was a big question as the teams gathered and readied their systems. Before the Live-Fly Competition, no team had fielded more than four aircraft at the same time. The first day, the competing teams raised that number to 20 aircraft on a side, in heterogeneous groups of fixed-wing UAVs and quad-rotors. Two short days later, the championship match had 60 aircraft flying—25 on 25 competing, with five additional aloft per team circling in reserve, again in mixed groups.
“One of the most exciting outcomes of it,” Chung said, “has been the opening of the eyes and the imagination—not only of the Cadets and Midshipmen, not only of the researchers that helped create this technology, but also of the attending warfighters and operators who were able to watch the Cadets and Midshipmen engage in swarm-versus-swarm battle in live flight and understand both what swarms are able to do and what they are not yet able to do.”
“I'm incredibly proud of the Cadets and the Midshipmen who have put so many hours into this Challenge,” said acting DARPA Director Steven Walker. “To my knowledge, this is the first time we’ve flown swarm against swarm at this scale. And the creativity these students showed in their design of offensive and defensive tactics bodes well for our Services’ future capabilities.”
DARPA often does a Challenge event instead of a standard research program when the Agency knows a field of technological innovation is ripe for fast progress but would benefit from incentives to get participation from the broader research or Service community. For the Service Academies Swarm Challenge, DARPA invited the young officers-in-training to develop and flight test novel ideas for how best to use swarms in future wars.
That goal is especially relevant today in light of the trend in military operations to maximize human-machine cooperation, whether the machines are UAVs, unmanned undersea vehicles, unmanned ground vehicles, or even satellites, said Brad Tousley, director of DARPA’s Tactical Technology Office, which oversaw the competition. The Service Academies Swarm Challenge focused the students on the fact that in the future—when these capabilities are in real military systems—they may have the opportunity to use swarms of much larger numbers of unmanned entities.
“One of DARPA’s jobs is to make sure that every fight we go into is an unfair fight in our favor,” Tousley said. “That means ensuring that these Midshipmen and Cadets as future officers can use unmanned systems in a swarm configuration more effectively than their adversarial counterparts.”
The Service academies tested their tactics in a modified version of Capture the Flag. Two teams at a time played inside the Battle Cube, a cubic airspace 500 meters on a side, 78 meters above the ground. Each team was given 20 fixed-wing UAVs and 20 quad-rotor UAVs and, under the rules of play, could field a mixed fleet of up to 25 UAVs for each of two 30-minute battle rounds. Each team had to protect its “flag” (a large, inflatable ground target) while trying to score the most points before time ran out.
Teams had three ways to score points: air-to-air “tags” that used simulated (virtual) weapons and sensors to fire on an opponent’s UAV in flight; air-to-ground “tags” earned by physically landing a UAV on the opponent’s flag; and accomplishments in swarm logistics by launching as many UAVs as quickly as possible and keeping them aloft as long as possible. The team that won both of its matches won the competition.
The three matches saw successively higher scores and more complex gameplay, as the teams gained and learned from their experience:
--Sunday, April 23: In this opening game, Air Force defeated Army 58-30 in a 20-on-20 battle. Air Force’s 10 fixed-wing UAVs and 10 quad-rotors had 13 air-to-air tags and no air-to-ground tags, while Army’s 15 fixed-wing UAVs and five quad-rotors had six air-to-air tags and one air-to-ground tag. Army took an early lead but Air Force's ability to quickly amass a larger swarm proved to be the decisive factor.
--Monday, April 24: This classic match-up saw Navy defeat Army 70-37 in a 20-on-25 battle. Navy’s 11 fixed-wing UAVs and nine quad-rotors had 16 air-to-air tags and five air-to-ground tags, while Army’s 17 fixed-wing UAVs and eight quad-rotors had eight air-to-air tags and three air-to-ground tags. The match was all about the fixed-wing aircraft, with only one successful air-to-air tag by a quad-rotor.
--Tuesday, April 25: Navy defeated Air Force 86-81 in a hard-fought championship match in which the lead changed four times before the clock ran out. Both teams launched every aircraft the game allowed, fielding the most of all the matches with 60 UAVs aloft at a time—25 on 25, while each team launched and held five additional craft in reserve. Navy’s 20 fixed-wing UAVs and 10 quad-rotors had 19 air-to-air tags and six air-to-ground tags, while Air Force’s 18 fixed-wing UAVs and 12 quad-rotors had 18 air-to-air tags and four air-to-ground tags. The large number of aircraft pushed the experimental networking infrastructure to its limits and made it harder for both teams to send commands and update tactics.
Each team developed multiple tactics as well as an overarching strategy for implementing them during matches. DARPA is currently evaluating the data from this preliminary research for potential applicability to future military missions.
The Service Academies Swarm Challenge highlighted many potentially fertile areas of future swarm-related research, Chung said. Topics of particular interest include efficient intra-swarm communications, improved situational awareness among swarm members, and developing human-machine interfaces and other tools that allow swarm commanders to more effectively use swarm capabilities. It also underscored the value of installations such as Camp Roberts, which has the restricted airspace, infrastructure, and experience to host large-scale UAV experiments.
The three Service Academies are poised to extend the research that supported the Challenge. They are keeping all the UAVs, software, and other infrastructure that DARPA provided. And they have created basic curricula and capstone project frameworks for conducting unique, accelerated research and field experiments on swarm tactics. Most important, they now have dozens of students who have worked side-by-side with leading-edge researchers and operators experienced with advancing the state of knowledge of swarm systems.
“There are seeds of genius in these Cadets and Midshipmen and I hope that one day some of them will return to DARPA as program managers,” Chung said. “There's a bright future for these young military leaders, in that they now—having experienced the cutting edge of technology—can help shape how that technology will be used in the future.”