Fearing the U.S. is over-reliant on GPS technology, Congress has directed the defense community to find positioning, navigation and timing alternatives — and a range of possibilities was presented at the PNT Technology Showcase Feb. 26.

The Center for Technology, Research and Commercialization hosted the event at Catalyst Campus in conjunction with TechnologyMarketplace.org.

The showcase was held in anticipation of a PNT accelerator program, scheduled for fall of 2018, according to an email from Catalyst Accelerator Program Director Rebecca Decker.

It brought together presenters from Air Force labs, industry and academia to speak about PNT technologies with military, industry, venture capitalists, entrepreneurs and federal employees.

Keynote speaker Rear Adm. (ret.) Liz Young, who completed her government career as director of the Systems Engineering Directorate in the National Reconnaissance Office, started by saying she was “not sure our reliance on GPS can be overemphasized — but I’ll try and do that.

“Everyone, whether they know it or not, depends on PNT and thus GPS,” she said. “Precise knowledge and location and time underpins virtually every mission the DoD executes.

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“Our ability to employ precise munitions which require PNT has given us a tremendous warfighting advantage for a number of decades,” Young added.

GPS is an outstanding positioning, navigation and timing system, she emphasized, but it can’t be the only system.

“GPS is important. GPS is a fantastic system. GPS underpins our way of warfare,” Young said. “It is critical to the global economy and critical to our economy and it would be imprudent — foolhardy — to only have one source of something that is that important to everything we do.”

Air Force Research Laboratory Sensors Directorate electronics engineer Mark Smearcheck agreed.

“You just heard a message of ‘Don’t abandon GPS’ — I’m going to give that exact same message,” he said. “If I was to challenge everybody in this room to name all the features you’d like in a navigation system, you’d probably say: global coverage, it works in all weather, I can turn it on and it tells me where I’m at, the user equipment costs me next to nothing, and it’s a just-works kind of system.

“Well guess what: That’s pretty much a GPS. So we have our challenge cut out for us [in searching for alternatives] because GPS solves lots and lots of problems.”

For the military, global precision attack, special operations, unmanned systems, communications, autonomy, advanced weapons, and cooperative platforms all depend on PNT.

“And right now when someone says ‘PNT’ it usually just means ‘GPS’ — and we can’t have that be the case anymore,” Smearcheck said. “PNT needs to mean ‘GPS when it’s there,’ and it needs to mean other stuff when it’s not. And it’s our challenge in this room to figure out what that other stuff is.

“GPS is a critical enabler of so many things, we’re ultra dependent on it — but what we really need to look at is guaranteeing that we can maintain our access to GPS, that we can fight through any issues that we have and continue to improve that.”

Smearcheck also emphasized the sometimes-overlooked timing element of GPS.

“Anybody who took money out of an ATM today, listened to a radio station, talked on their cell phone, got on the internet — guess what, that’s all controlled through GPS time. So GPS is a lot more than just positioning. It’s something that we’re dependent on for everything, essentially.”

Young looked back to a time before GPS.

“The [historic] stories of heroism often start with, ‘We were lost’ — and that’s part of the reason they had to be heroic,” she said. “The ground forces always have to answer three questions. Where am I? Where are my forces and the other friendly forces? Where’s the bad guy and what’s the best path to get to them and take them out?

“Back in the day before GPS, picture a lieutenant, in a swamp, in the middle of the night, in the pouring rain, with a compass and an old map. The advancement of GPS has allowed individual soldiers and small units to know exactly where they are. That’s a huge advancement.”

It also became integral to, and pushed the advancement of, superior command and control networks.

“Not one country has made such exquisite use of PNT as the United States. We have revolutionized warfare with how we use GPS. … Back in the wars of yore it took a lot of planes to take out a target; a strike package was a lot of airplanes. Today a strike package is three planes, and we expect to take out three targets with that, and that’s because we are the masters of PNT,” Young said.

“So what’s the threat? The way we wage war rests on PNT — and that at the end of the day is the threat.”

Smearcheck pointed out that even if the technical challenges of a GPS alternative could be solved today, it would still present “a huge acquisitions challenge.”

He focused on the use of an open architecture for PNT.

“Use GPS when you have it, augment with other sensors when you need to do that — and the biggest thing is just coming up with a system that we can respond to threats quickly with, we can update at a reasonable cost to address those new threats…” he said. “What we’re really looking to do is build up an architecture, a system, such that we can turn new sensors on and off, and we can leverage existing sensors we already have on our platforms…

“Don’t give us another single-purpose box that’s only solving today’s problem, when there’s going to be a lot of other problems that we haven’t thought of yet.”

Other presenters included Ryan Blay of The Colorado Center of Astrodynamics Research, who presented a hybrid algorithm that combines Time-Difference-of Arrival and Power-Difference-of-Arrival localization techniques; Kurt Williams of GPS Source, who presented the Sentry Scout Resilient Positioning Navigation and Timing solution; and John Wallace of Rincon Research Corporation, who presented the Raptor Zynq UltraScale + MPSoC SDR Development Kit.