U.S. Army Yuma Proving Ground an unmanned aircraft testing hub

The great blue yonder is not an isolated locale. A busy airport at a major city in America routinely hosts 1500 takeoffs and landings in a single day. The sheer volume of national air traffic necessitates a vast infrastructure run by thousands of air traffic controllers who orchestrate its safe passage from destination to destination, a stressful job that requires meticulous planning and reporting by every aircraft.

Rigid adherence to the system permits this vital network to proceed with few incidents, but negates the spirit and ability to leap into the next epoch of air travel -- refinement of unmanned aerial systems (UAS), which are pilotless craft controlled autonomously. Our skyways are so busy that testing even the tiniest of these long-range marvels in a safe, sustained manner is problematical. However, these restraints do not exist at U.S. Army Yuma Proving Ground (YPG) in southwest Arizona.

"UAS testing is one of the most diverse commodity areas we have," said Mary Beth Weaver, lead test director for UAS testing at YPG's Aviation Systems Division. "We test everything from one pound platforms to very large platforms that weigh more than a ton."

YPG is the second-largest installation in area in the Department of Defense, which allows for the testing of long-range artillery projectiles and other weapon systems without fear of hitting occupied areas. Less intuitive, perhaps, is that YPG's vast size also includes nearly 2000 square miles of restricted airspace. This vast holding is used by testers at YPG's aviation systems branch for extensive testing of a variety of UAS platforms. The proving ground seems as close to an ideal venue for UAS testing as can possibly exist. The clear, stable air and extremely dry climate where inclement weather is a rarity makes it highly coveted.

"We have a low density altitude, which translates into enhanced engine performance," said Pat Franklin, a test director for the Aviation Systems Division "We also have a natural terrain bowl surrounded by high terrain on three sides, which keeps weapons, laser emissions and radio frequency energy from propagating out and disturbing anything outside of the proving ground."

More interestingly, this testing takes place across all stages of the development cycle. Though more than 90% of the YPG workload is conducted on behalf of military customers, private industry clients are attracted to the same expertise and range characteristics that military testers covet.

"We have a very diverse customer base with many different test objectives," said Weaver. "On a given day we might be working on a command and control system while at the same time supporting another customer who is developing a new airframe. There are no cookie-cutter tests here."

History

Small aircraft drones have played a role in Army training since World War II. The gradual adaptation of these small target craft to more sophisticated functions has been an important part of YPG's test and evaluation mission for decades. The first hangar at Castle Dome Heliport, one of YPG's UAS launching points, was constructed in the late 1950s to support a drone competition. More important for UAS testing at the proving ground, however, was the presence of the AH-56 Cheyenne helicopter in the early 1970s, which resulted in an influx of aviation testers from Maryland's Aberdeen Proving Ground and the construction of a substantial amount of infrastructure like laser and optical tracking sites that can support both manned and unmanned aviation testing.

In the latter 1970s, construction started on a site for a vertical lift UAS testing site, which began as a 250 foot square asphalt landing pad and a lone double-wide trailer that served as a command center. Over the years, the size of the pad was doubled and an airstrip was added to accommodate fixed-wing air vehicles, four additional UAS shelters were constructed, an additional trailer was brought in and a large earthen berm was added to shield the command center from tests involving weapons fires as the next decade brought efforts to weaponize what had previously been platforms that were meant only for surveillance.

Testing

In the recent past, a number of unmanned aircraft have undergone testing at YPG, from the A160 Hummingbird, to the Fire Scout, Shadow, and Hunter. Large or small, fixed or rotary wing, UAS are exquisitely intricate machines that must prove far more than the difficult enough basic question of whether or not it they are capable of flight. Like their manned cousins, UAS must be able to fly stably while supporting functioning sensors and accurate weaponry, and YPG is always busy testing the machines' ability to do this and more.

"UAS have shown their utility and value, and everyone is clamoring for them," said Weaver. "Any time you take a Soldier out of harm's way, it is beneficial. Unmanned aircraft provide much more accessibility and flexibility."

Weaponizing any aircraft platform is a highly complex business, but is even more challenging with unmanned systems. Testers have to take into account a variety of effects of firing a missile, most notably the thermal and blast overpressure effects of firing and how it impacts the aircraft's sensors and the ability of the aircraft to maintain stability in flight. The data needed to make such a determination includes measurements of pressure, temperature, and vibration, all of which require sophisticated measurement instrumentation. One recent test on a vertical lift UAS required test officers to construct a three-story tower and tether the running craft's landing gear to the top, after which the test rocket was loaded using a cherry picker bucket. Tests taking place early in the development cycle, on the other hand, might simply mount the gun tube to a hard stand to collect test fire data.

Whether the platform is weaponized or not, YPG testers are frequently concerned with the sophisticated sensors possessed by UAS, as well as the craft's ability to sustain flight for long periods of time. YPG's testers can accommodate every phase of the developmental process.

"We have the infrastructure here to easily move from testing one level of platform maturity to another," said Franklin. "It is good synergy for the private industry customer."

YPG's unsurpassed capabilities allow for extensive testing of platforms that blend conventional aircraft with unmanned systems. Further, all of these tests can be conducted concurrently and, typically, without having to compete for runway and airspace with manned fighter jets as at other installations. Another critical bonus of testing at YPG is the presence of a wealth of other infrastructure meant for other sectors of YPG's broad test mission that can be leveraged to support UAS evaluations. YPG is home to things like technical and tactical targets, as well as generator and combined maintenance shops, all of which are useful for UAS testing. YPG testers can even do cooperative tests with artillery firing.

"We have the air and ground resources a customer needs to challenge their system," said Weaver. "Flying is one thing. Once you have achieved flight, what is your purpose for flying? We have everything you need to demonstrate a platform's utility."

"Other installations may have one aspect or another, but not the whole package that YPG offers," added Franklin.

Safety

Most of the airspace over the United States is unrestricted. To fly their craft in these conditions, UAS developers must acquire a certificate of authorization (COA) from the Federal Aviation Administration. This is a lengthy and exhaustive process that can take months and is specific not only to the aircraft, but the specific configuration of the aircraft. Thus, if developers want to modify the UAS in response to their testing, they must get a new COA after every change. Achieving these stringent conditions is unrealistic for an untested UAS in the early stages of development. Additionally, an important part of the developmental process is testing worst-case scenarios. It is unlikely that the Federal Aviation Authority would allow such testing in the national airspace. YPG's restricted airspace, on the other hand, covers miles and miles of land far from any populated area.

Future

Although the government remains the primary consumer of these systems, the Government Accountability Office (GAO) predicts the number of these cutting-edge craft in civilian hands will more than quadruple in the next five to ten years, performing a variety of missions with less risk, cost and pollution than a conventional manned aircraft. Futurists look forward to the day when the military technology will be adapted to the commercial marketplace. The technology transfer between military and civilian applications goes both ways, too. One portable UAS used for surveillance by Soldiers was originally used by commercial fishing operations as a low-cost, long-endurance aircraft for spotting schools of tuna.

Despite their vast potential, the same GAO report identified a lack of airspace for test and evaluation as an impediment to UAS progress, a void that YPG is actively filling for both government and private industry.

YPG's UAS workload indicates the state of the art in the field, with recent tests evaluating new composite materials that seek to improve an airframe's fuel efficiency and aerodynamics, as well as advanced acoustical sensors and micro-sized aircraft systems that can be easily carried and deployed for short distances by ground units conducting operations such as house-to-house searches.

"Without a doubt, it's the future," Weaver said. "The day is soon coming where there will be an even ratio of manned and unmanned aircraft. Eventually, one ground controller will be flying multiple unmanned aircraft simultaneously. There are already several initiatives that do this."

YPG is firmly poised to continue UAS testing for military and industry customers.

"At YPG there is significant room for future site expansion," said test officer Jerry Crump. "Other test sites don't have the combination of experience and capabilities that YPG has."