EAB Q&A: What are the key challenges and promising trends for GNSS/PNT?

What are the key challenges and promising trends for GNSS/PNT over the next three to five years?

Bernard Gruber

“In 2023, the GPS program celebrated its 50th anniversary. It has had untold positive impacts on the world. I strongly believe this trend will continue through GNSS and complementary PNT systems for the next 50 years! That said, continuing challenges faced in the era of great power competition — specifically, to disrupt, deny, and destroy PNT capabilities — pose a clear and present danger. Ingenuity, competition, and strong coalitions will drive how we think and how we utilize our incredible resources – human and system – to persevere.

Unfortunately, challenges will always exist. Since the beginning, the GNSS community has had to deal with jamming threats, such as pervasive black market ‘cigarette lighter’ jammers, militarily sophisticated ones, or brute force high powered systems. This challenge will not go away. The burgeoning of artificial intelligence and machine-to-machine computations offers an opportunity and poses a threat: as commercial and government entities embrace these technologies, they exponentially increase the need to adapt.

Several promising trends will continue. Through the hard work of countless governmental organizations supporting the National Coordination Office, periodicals such as GPS World, academic papers, conferences and symposiums, marketing and communications, the public is now aware of how vital GNSS and PNT systems are. Second, buyers, operators, and users will demand that robustness be built into systems by anticipating needs such as increased cybersecurity, assured access, and tiered defense schema.

Third, innovative technical trends will drive increased processing power, cybersecurity/encryption toughness, signal diversity, adaptive antennas, and network augmentations, while an ever-increasing focus on model-based engineering and digital twins will allow us to field and learn faster. Additionally, as signal diversity grows, the opportunity for software-defined radios that utilize authenticated and available signals while ignoring others automatically will mature; programs such as the NTS-3 demonstration will at minimum force the decision of how we adapt.”

— Bernard Gruber
Northrop Grumman

Jules McNeff

“Trends have emerged and evolved over the last three decades — since GPS became operational — that addressed earlier challenges and yet have created new, and possibly more daunting, ones. Early issues with awareness and acceptance of the need for continuous, precise positioning, navigation and timing (PNT) have been overcome, and the markets and governments have responded with a proliferation of PNT services — both space-based and other.

I’ll leave the market trends and opportunities to our industry colleagues and focus more closely on some remaining challenges that are particularly vexing to me. That requires stepping outside the comfortable GNSS/PNT-as-a-technology engineering and science bubble full of topics for collegial international cooperation. Instead, one must look at GNSS/PNT as an incredibly valuable tool for public safety, political and economic advantage, and military dominance, all separate, but closely interrelated and so as a tool to be protected. Other nations, some unfriendly to the United States, recognize the political/economic reality and are deploying PNT services to compete with GPS and erode international public confidence.

The U.S. government appears complacent and naively unwilling to accept that changes are necessary in its approach to international economic competition in PNT technology over the immediate future. Similarly, in the public safety arena, most of U.S. critical infrastructure (CI), an area of federal government responsibility, is well-known to be vitally dependent on GPS to function. However, the government agencies responsible for CI have been beyond reluctant to implement needed resilience measures, specifically regarding the terrestrial enhanced Loran (eLoran) system, which would provide substantial resilience if GPS service were lost or disrupted. This is despite multiple requests over the last decade from Congress and the National PNT Advisory Board to recapitalize eLoran.

At the same time, friendly and hostile foreign nations invest in their own eLoran systems to bolster PNT resilience within their sovereign territories. Knowing this, the United States cannot be happy with a situation that threatens economic and national security, yet it persists. Finally, and also important to public safety, we need to get serious about how PNT positions (geoaddresses) are reported to the public – important for economic purposes and specifically for incident/accident location and emergency response operations of all kinds. Continuing reliance on lat/lon as a default or on unique proprietary methods is both ineffective and dangerous given the ready availability of the U.S. National Grid as a public resource, as identified in the U.S. Federal Radionavigation Plan. As with eLoran above, the public safety challenge is to save lives and livelihoods and not allow them to remain at risk.

— Jules McNeff
Overlook Systems Technologies 

Jean-Marie Sleewaegen

“Recent years have seen a spectacular boost in the number of global navigation satellite systems (GNSS) satellites and signals. The launch pace has now slowed down, which does not mean the end of GNSS innovation. On the contrary, now comes the time to exploit and get the best out of all these new signals and services.

One of the first benefits of signal diversity is improved resilience: the more signals, the more fallback options in case of jamming or spoofing. Designing the optimal blend of all the constellations and signals into a precise and resilient PNT solution is and will remain a major innovation challenge in the industry. The recent introduction of Galileo OSNMA and the announcement of authentication services by other systems will play a key role in this evolution.

Having many types of signals also means that there are many ways of dealing with them. This is particularly visible in the current PPP-RTK offerings. Various service providers use different correction formats as well as protocols and this complexity is still too exposed to users. A key challenge will be the standardization and consolidation of the correction environment in a multi-constellation and multi-signal context. At the receiver side, this involves evolving from a vendor-specific to a correction-agnostic approach.

In the next few years, the focus will also expand beyond classical GNSS, with the announcement of the first low-Earth orbit (LEO) LEO PNT constellations, promising improved precision, resilience, and security compared to traditional medium-Earth-orbit (MEO) GNSS. The promises and challenges of  LEO PNT constellations and their interoperability with GNSS will undoubtedly foster major innovations in the PNT industry.”

— Jean-Marie Sleewaegen 
Septentrio 

Michael Swiek

“A basic question for the next three to five years is how will we be receiving PNT, or P, N, and/or T individually or in combination and from where? We have become accustomed to receiving reliable PNT from government-operated MEO satellite constellations. However, new options appear to provide PNT or P, N, or T from LEO constellations, terrestrial beacons, etc., from both government and private sector providers. These options can help address vulnerabilities in traditional GNSS services and provide options for new applications. The question becomes one of coordination and integration of diverse solutions. The challenge is managing the technical, market and regulatory elements while not undermining existing stable infrastructure or future innovation.”

— Michael Swiek 
GPS Alliance