Congressional auditors are doubling down on calls for the U.S. Air Force and Army simply to implement their own so-called open-systems architecture policies when it comes to unmanned aircraft systems, according to a July 31 report from the Government Accountability Office (GAO).

The review is the latest in a more-than-decade-long reporting effort by GAO to dissuade the military’s and industry from acquiring and providing proprietary systems “that limit opportunities for competition and cannot readily be upgraded because the government is locked into the original suppliers.”

For UAVs in particular, the effort comes as the systems have earned a key role in the U.S. arsenal via the Afghanistan and Iraq wars, but also as urgent operational needs fade and officials and executives look to their future use, especially in a more fiscally restrained budget environment.

“Legacy [defense] programs that we have reported on in the past did not implement an open systems approach early and are now facing difficult and costly system modifications later in their respective service lives,” GAO told the Republican chairman and ranking Democrat on the House Armed Services tactical air and land forces subcommittee. “The B-2 bomber and the C-130 aircraft are two examples.”

GAO acknowledged that the Pentagon has increased efficiencies by using an open systems approach for some of its past acquisition programs, as well as its largest UAV programs — but the armed services still vary widely to the extent to which they have adopted open systems for the 10 largest UAVs. The Navy Department, which includes the Marine Corps, is “leading the other services,” auditors say.

Three of the Navy’s four current and planned UAV programs — Stuas, Triton and Uclass — have incorporated, or are planning to use, an open systems approach from the start of development in key components such as the air vehicle, ground control station and camera and radar payloads, according to GAO. The Fire Scout did not.

But none of the Army or Air Force UAV programs incorporated open systems from the start because, according to Army and Air Force officials, legacy UAV programs tried to take advantage of commercial off-the-shelf technology or began as technology demonstration programs. Still, at least four of the six of these Air Force and Army UAVs are starting to utilize an open systems approach, primarily for the ground control station of fielded aircraft during planned upgrades, GAO noted.

“The Army and Air Force did not originally plan to make the air vehicle, ground control station or payloads of their UAS programs open systems,” GAO told lawmakers. The Army’s three UAV programs, Hunter, Shadow, and Gray Eagle, were all developed as proprietary.

“The Air Force has had limited success in modernizing its UAS to include open systems,” GAO continued. The Reaper program has plans to upgrade to an open ground control station, but the remainder of the system remains proprietary. The other two UAVs, Predator and Global Hawk, in their planning documents stated an intention to introduce open systems later in their life cycles. “However, Predator’s age and Global Hawk’s fiscal constraints prevented them from adopting an open systems approach. As a result, the two systems remain largely proprietary and are now facing challenges sustaining and upgrading their systems.”

After the Air Force and Army programs were started, both armed services rolled out policies that require open systems to be included in a program’s acquisition strategy. Moreover, the Pentagon’s 2010 and 2012 Better Buying Power initiatives now require programs at milestone B to outline an approach for using open systems architectures and acquiring technical data rights. A contract guidebook is expected to be issued this summer to help program managers incorporate open systems into their projects.

Still, as GAO noted, several officials and executives across the unmanned spectrum told auditors that top Pentagon officials still do not have enough inherent expertise and insight into programs to know whether open systems planning is happening. GAO says, “Until DOD takes action to overcome these challenges, the department will likely continue to invest in costly proprietary systems.”