Beginning with the next issue in the Thinking Aloud column, we will publish invited guest editorials, written by subject matter experts, policy leaders, user community advocates and key influentials in the worldwide GNSS community.

It is indeed a changing world of GNSS. Applications arise and flourish, then are overtaken by new ideas about what positioning, navigation, and timing (PNT) can do to improve the human condition.

What hasn’t changed is the need for skilled engineers to harness the hardware and—ever more important—the software solutions that underlie new GNSS products, applications, possibilities. The complex signal-processing algorithms will always need to be used to their fullest capabilities.

We must continue to address the means for integrating GNSS with other PNT technologies and the sensors that are revealing our world and the endeavors of its inhabitants in ever more detail.

And what also hasn’t changed is the need for quality reportage of GNSS policy, engineering, and state-of-the-art practice. GNSS journalism that makes a difference, that chronicles the way ahead charted by the pioneers and masters of the art and science of PNT.

Richard Fischer
Publisher, Inside GNSS

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Case in point: as of year-end 2017 I am promoting myself to Editor Emeritus of Inside GNSS and turning to some unfinished business that I have with life. Of course, after 28 years I still have some unfinished business with GNSS, this amazing technology and industry that has more growth ahead of than behind it, more prospects for innovation, more unfinished business than ever.

The Inside GNSS business itself — magazine, webinars, website, and so forth — will be advanced, expanded, and undoubtedly improved by my long-time partner in GNSS publishing, Richard Fischer, who entered the field in 2000 and has brought energy, intelligence, and expertise to the enterprise. The success of our sister publication, Inside Unmanned Systems (now entering its fourth year), bears further witness to his skills.

Richard’s leadership will be complemented by managing editor Stan Goff, and the long-time contributors to Inside GNSS’s success: our editorial advisors, our Washington and Brussels correspondents — respectively, Dee Ann Divis and Peter Gutierrez; the editors of Working Papers, GNSS & the Law, and GNSS Solutions; and the many members of the global GNSS community itself who have never been shy about sharing their ideas, insights, and opinions with us.

As for the unfinished business of GNSS, well, these are the topics that I will be watching most closely in the months and years ahead:

Achieving Full Capability. China and Europe must still build out their full global constellations and services. Meanwhile, Japan has to decide whether to fund an expansion of the Quasi- Zenith Satellite System to provide an independent regional capability.

Modernization. Russia still needs to overcome technology embargos and manufacturing issues to produce a next-generation GLONASS capability, while the United States works to finish an overdue upgrade of its operational control segment and third-generation GPS satellites.

GNSS Vulnerabilities. In the foreseeable future, jamming and spoofing will not magically disappear. But engineers, system integrators, and product designers will also have to consider the cybersecurity aspects of systems with which GNSS is combined. Signal encryption and authentication are necessary but probably not sufficient solutions.

Not by GNSS Alone. Assured PNT (positioning, navigation, and timing) remains to be ensured, depending in large part on successful integration with other PNT technologies.

GPS Launch Costs. The United States should reassess the trade-offs between continuing to include the Nuclear Detonation Detection System on GPS satellites and the weight and power requirements that make them so expensive to build and launch.

International Cooperation. Consensus and collaboration among GNSS providers — e.g., in spectrum, interoperability, interference detection and mitigation, performance monitoring, and mutually beneficial business initiatives — must continue to transcend the national politics that may afflict their relations in other areas.

Global View. Reciprocal recognition and acceptance of other GNSSes’ operation within national boundaries remain a sticking point and stumbling block to full exploitation of this critical infrastructure.

Integration on New Platforms. Autonomous, unmanned, and remotely piloted vehicles, vessels, and aircraft are only the latest, not the last, new places that we will find GNSS.

Technology Synergy. GNSS integration with other sensors, robotic systems, big data, and artificial intelligence has, in many ways, just gotten going.

Penetration into New Application Markets. Just when you think there’s no stone left unturned, a landslide of new uses for GNSS rumbles into view — disrupting old ways of doing business, bringing new precision and cost-effectiveness to new realms of human endeavor.

With such an abundance of unfinished GNSS business, I won’t stray too far. Readers can still reach me at gl**@********ss.com with inquiries, suggestions for authors and articles, and your own perspectives on this remarkable world of GNSS.

Glen Gibbons, Jr.
Editor

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Today’s headlines frame my thoughts about securing GNSS assets, which one expert has characterized as our “least visible and most vulnerable infrastructure.”

In the Columbia River Gorge, a National Scenic Area spanning the Washington-Oregon border, a 15-year-old boy has been accused of intentionally tossing fireworks into tinder-dry grass thereby starting a (thus far) 33,000-acre forest fire that has devastated a natural treasure. Meanwhile, in the latest incident of large-scale identity theft, credit-rating agency Equifax has belatedly acknowledged a months-long breach of its database in which 143 million personal records were reportedly accessed.

In one case, an individual — obliviously or purposefully — creates outsized havoc, in the other, a skilled team of professional thieves disrupt a global enterprise and endanger the financial well-being of millions.

Of course, we have headlines closer to the point, such as “Reports of Mass GPS Spoofing Attack in the Black Sea,” or “South Korea developing eLoran Network to Protect Ships” from North Korean GPS jamming.

These latter incidents, of course, arise from state-sponsored or –enabled actions. But, as with the Columbia gorge fire, personal behaviors — often harder to detect and prevent — can similarly afflict GNSS capabilities. In recent years, considerable attention has focused on the use of small GNSS jammers, also known as “personal privacy devices.” Perhaps the best-known case is that of a trucker trying to jam his vehicle’s own receiver who interrupted GPS-aided landing operations at Newark International Airport.

As the articles on jamming and spoofing mitigation in this issue of Inside GNSS reflect, the motives and methods of perpetrators vary. But, given the natural progression of information-sharing and widening expertise in GNSS — along with our cultural soft spot for making heroes out of rebels and outlaws — we can probably assume that the trend toward disruption will only get worse.

Some GNSS user groups have struck out on their own to ensure the security of their constituencies and their particular needs. Military users benefit from a variety of alternative PNT technologies such as geomagnetic mapping, vision- and image-based navigation, and chip-scale atomic clocks and inertial measurement units. The U.S. Federal Aviation Administration has decided to retain, for the time being, a minimum operational network of VHF omnidirectional range (VOR) facilities originally planned to be phased out with the introduction of GNSS.

Over time, some of these alternatives may migrate into the commercial and professional space — then again, they may not. And the vast majority of individual GNSS consumers have no organizations to advocate for their needs.

So, what is to be done? How can we ensure that the positioning, navigation, and timing (PNT) utility is available to all users, and not just those sectors with the resources to develop solutions for themselves? The future of location-based applications and enterprise — and the associated economic benefits — depend on a satisfactory answer to that question.

Multi-level threats clearly require multi-tiered responses that fit the corresponding scope and scale of different domains. At the system level, GNSS providers are exploring such measures as encryption, signal authentication, stronger signal power, and advanced signal designs.

National and international legal/initiatives include such efforts as regulating the sale and use of GNSS jammers and spoofers. Alternative PNT systems — for example, enhanced Loran (eLoran) — represent a potential multinational approach to the problem.

At the level of user equipment, several GNSS manufacturers are incorporating interference detection and mitigation (IDM) and antispoofing capabilities into proprietary products.

The variety of these initiatives and their advocates illustrates the breadth of concern about assured PNT, but also reflect the fractured nature of responses to the threats to GNSS. The situation calls for leadership with the expertise and stature to bring comprehensive solutions before the wider GNSS community.

The International Committee on GNSS has the membership and forum, if not yet the clear mandate, to impose such solutions globally. At the national level, the U.S. Space-Based PNT Executive Committee assisted by its expert advisory panel seems the most likely candidate for this role.

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Like many massive infrastructure projects, the NextGen program has suffered numerous setbacks, many self-inflicted. An August 2016 report from the Office of the Inspector General (OIG) of FAA’s parent, the Department of Transportation, noted, “FAA’s plans have proven to be unrealistic, lacking stable investment priorities and requirements for NextGen systems.”

With more than $7 billion in modernization funds already expended, the FAA is currently projecting costs of $14.8 billion from Fiscal Year (FY) 2015 to 2030, according to the OIG report. Despite the characterization of NextGen as being wildly over budget, however, total cost estimates for the program “have evolved, but not increased markedly since FY 2004,” the OIG says. The president’s proposed FY18 budget requests $988 million for continued NextGen development, down from $1.055 billion in FY17.

As other infrastructure modernization efforts involving GNSS have shown, getting the technology right is the easy part. The Global Positioning System has a 22-year operational history to bolster expectations about its performance, which has continued to improve steadily. The arrival of other GNSS systems has only strengthened this technological resource.

Instead, the sticking points arise from such issues as enterprise architecture, systems integration with other technologies such as data communications and weather forecasting, interagency cooperation, human factors, cybersecurity, operational procedures, and regulatory updates to accommodate modernization.

Like America’s healthcare insurance system, modernization of the National Air Space is more complicated than casual observers might think.

NextGen needs to happen, first, because it will pay off in improved aviation operations, greater capacity, and better use of the crowded National Air Space (NAS). FAA modernization has already provided $2.7 billion in savings from such things as less usage of fuel and is expected to provide another $160 billion in benefits through NextGen’s targeted 2025 completion date.

Efforts so far have barely scratched the surface of what GNSS and other NextGen technologies can provide.

However, the need to get NextGen back on track has gained heightened urgency with the renewed push to privatize U.S. air traffic control (ATC). On June 27, the House Transportation and Infrastructure Committee approved a measure that would turn the nation’s taxpayer-funded ATC infrastructure and operations (carried out by 30,000 public employees) over to a nonprofit organization controlled by aviation industry representatives.

The measure, previously backed unsuccessfully by House Transportation Committee chairman Bill Shuster, has gained important support from President Donald Trump.

NAS modernization is a perhaps uniquely complicated undertaking with many elements subject to inevitable changes as technologies and operational environments (including the political and economic context) evolve. NextGen is a moving target being shot at from a moving platform.

Attempting to privatize air traffic control at this point in the process would throw a very large monkey wrench into some very delicate works in progress. As Senate Appropriations Committee Chairman Thad Cochran (R-Miss.) and committee Vice Chairman Sen. Patrick Leahy (D-Vt.) said in a February 28 letter to Senate Commerce, Science and Transportation Committee Chairman Sen. John Thune, “If air traffic control were separated during this critical period of technological advancement, the progress already being made to synchronize investment from government and industry related to safety, equipage, training, operational changes, and overall integration would be lost.”

And the FAA, not some newly convened group dominated by stakeholders with their own interests in mind, should continue to lead this project. As a special National Research Council committee concluded in a congressionally mandated analysis of NextGen in 2015, “Replacing or upgrading systems while continuously and safely operating the whole system is an intricate undertaking, a process that the FAA seems to have mastered.”

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Long-overdue approval of the request should be expedited by the FCC.

For several years the European Union (EU) has sought a waiver for its Galileo system from Federal Communications Commission (FCC) licensing requirements — the so-called Part 25 rule to operate in this country.

Long-overdue approval of the request should be expedited by the FCC.

The initial request, channeled through the U.S. State Department, came in October 2013. On January 30, 2015, the National Telecommunications and Information Administration (NTIA) asked the FCC to seek public comment on the EC’s waiver request and recommended granting the exemption to the Galileo system, which met NTIA’s criteria for such waivers.

Nearly two years passed before the FCC, on January 6, issued the public notice sought by NTIA. The comment period closed on March 23 and drew 18 responses, including replies to other submitters’ comments.

The Galileo exemption would apply to three frequencies, but it’s the swath of RF spectrum at 1559–1591 MHz, within which GPS military and civil signals also reside, that are primarily at issue. That GNSS E1/L1 spectrum adjoins a band (1525-1559 MHz) in which Ligado Networks, the successor of LightSquared Inc., would like to build a terrestrial broadband network that has been shown to interfere with many GPS receivers.

Comments made to the FCC strongly favored granting the exemption — with two exceptions. Inmarsat, an international satellite communications organization, raised concerns about out-of-band (OOB) interference from Galileo. Inmarsat and the EC subsequently issued a joint statement supporting a test campaign to assess the risk of OOB interference from Galileo E1 and agreed to mitigate such effects if they appeared.

The other negative response, predictably, came from Ligado Networks, which argued that the waiver should not be granted until after demonstrations that Galileo won’t interfere with Ligado’s proposed operations and that the addition of Galileo would not make user equipment more vulnerable to Ligado’s terrestrial transmissions. 

Given that Ligado’s broadcast power would be much stronger than Galileo’s, the company’s first objection seems rather disingenuous. As for the latter issue, Galileo E1 has long operated within the same frequency as GPS L1 and P(Y)-code and within the same receivers without any substantive problems. Moreover, as the EC pointed out, Galileo has transmitted the PRS signal since 2006 “without reports of interference to systems operating in the band below 1559 MHz.”

In contrast to the limited grounds for denying the Part 25 licensing exemption, several compelling arguments exist for granting it:

National Security. Use of Galileo can further protect critical U.S. infrastructure, such as the national electrical grid and civil aviation, and enhance military operations. In a report attached to the National Defense Authorization Act for Fiscal Year 2017, the U.S. House Armed Services Committee urged the FCC to quit fooling around and act on the waiver request.

Foreign Relations. The EU represents one of the United States’ oldest and closest allies, reflected in a 13-year-old agreement that established similarly designed binary offset carrier (BOC) waveforms as the basis for new civil signals at L1/E1: the GPS L1C and Galileo’s Open Service at E1. The U.S.-European relationship is going through a rough patch right now that could be smoothed by granting the Galileo exemption as soon as possible.

Emergency Services. Unauthorized signals cannot be used for official or regulated applications such as law enforcement or 911 services without FCC approval. The EC’s request received support from NENA, the national emergency number association, which argued that additional satellite signals from Galileo would significantly improve 911 services.

GNSS Market Growth. In bilateral and multilateral negotiations the United States has long argued for ensuring a “level playing field” in commercial markets that does not favor one GNSS system over another. Not granting the exemption risks tit-for-tat treatment of GPS by other nations with their own GNSS systems. 

GPS Protection/Backup. In 2010 the Obama administration adopted a space policy that said foreign GNSS services could be used “to augment and strengthen the resiliency of GPS.” Use of Galileo would aid detection of spoofing, improve interference rejection, and provide a needed GPS backup. It’s time for the FCC to move ahead and grant the Galileo request.

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Looking over the initial budget of the Trump administration, we can safely say that the president and his timorous collaborators on Capitol Hill have a maximalist concept of providing for “the common defense” and a minimalist one for promoting “the general welfare,” two of the six missions enshrined in the preamble of the U.S. Constitution.

At first glance, that might suggest that the prospects for GPS are better than ever. After all, as operator of the Global Positioning System, the Air Force appears likely to benefit from the president’s proposed addition of $52 billion in defense spending for fiscal year 2018.

Certainly that budgetary largesse must be able to accommodate the relatively modest increments needed to accelerate the fielding of M-code–capable GPS receivers and get the next-generation satellite and control segment programs back on track.

One of the few widely praised appointments that Trump has made was naming Jim Mattis to head the DoD. The result of a timely recommendation by former Defense Secretary Robert Gates, the appointment assured a self-possessed, battle-tested, and disciplined leader for the department.

Confirming the nomination of Boeing executive Patrick Shanahan to serve as Mattis’s deputy would add another leader familiar with the industry culture and departmental mission of the nation’s defense community. Among the DoD deputy secretary’s responsibilities is co-chairing the National Space-Based Positioning, Navigation, and Timing Executive Committee (PNT ExCom), the high-level interagency group that oversees GPS policy management.

Nonetheless, the president’s proposed financial enhancement of an agency already consuming about half of the federal government’s discretionary spending seems not merely excessive but counterproductive, given the offsetting reductions proposed for civil agencies.

With defense spending now more than $600 billion, recent expressions of concern over U.S. military readiness may stem more from management failings and misallocation of resources than inadequate budgetary support.

Yes, it’s an increasingly hard-power world, but successfully addressing global problems necessarily requires soft as well as hard tools. Echoing Peggy Lee, we might ask of defense spending, “is that all there is” to ensuring national security?

We have yet to learn where, for example, the White House’s proposed 29 percent cut in the State Department’s budget might fall.

Let us hope that it spares the Office of Space and Advanced Technology. That small entity leads interagency coordination on civil space-related international agreements with other nations’ space agencies. And it plays a key role in the implementation of the U.S. National Space Policy focused on dual-use space applications including GNSS.

The space and advanced technology office provides the staff and expertise for U.S. participation in the UN-affiliated International Committee on GNSS (ICG). Over the 12 years of its existence, the ICG has gathered up all the national players involved with GNSS in a cooperative venture. Its ongoing efforts not only help prevent adverse effects of one GNSS on another, but have also encouraged interoperability among these systems, collaborative projects, and common efforts to head off external threats to GNSS in general.

Meanwhile, the GNSS community should remain vigilant against the possibility that a proposed 13 percent reduction in the Department of Transportation (DoT) will reach the Office of Positioning, Navigation and Timing & Spectrum Management. Through such activities as the Adjacent Band Compatibility Assessment, this DoT group has helped defend GPS against domestic threats such as those posed by the LightSquared initiative to use nearby RF spectrum for high-powered wireless wideband service.

The current administration’s posture in the world often seems not so much an “America first” policy as an “America only” vision. And while the collateral damage from liberal economic globalization over the last four decades certainly demands review of our industrial, tax, and trade policies, it does not mean that the United States can ignore the fact that our nation is embedded in an international matrix inescapably held together by technology, transportation, demographic shifts, and cultures as well as commerce.

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Sometimes, of course, unpredictability is in the immanent nature of things. Despite advances in meteorological technology and science, weather continues to prove fickle. Foreknowledge of earthquakes remains difficult to pin down in space and time.

As with the notion of “disruption,” unpredictability can be useful. A move in chess or go, for instance. Or in the case of cuisine — say, when usurping Taco Thursday with chicken tagine. Even in negotiations, an unanticipated gambit can change the outcome positively.

Sometimes, of course, unpredictability is in the immanent nature of things. Despite advances in meteorological technology and science, weather continues to prove fickle. Foreknowledge of earthquakes remains difficult to pin down in space and time.

In matters of infrastructure, however, unpredictability is rarely a plus. Discontinuing a bridge project halfway across the river is an expensive exercise. Eliminating a health insurance program can bring unforeseen consequences.

So it is with GNSS programs. Engineering change orders are an expensive proposition that have — as with many military technology innovations — bedeviled the program since the beginning. Mid-program changes in requirements or addition/ subtraction of capabilities have often put GPS modernization on a long and winding road.

Simply implementing planned upgrades is hard enough — satellite-ranging cross-links, for example, still not fully operational 20 years after conception. Accommodating unplanned changes are even more so.

The good news is that — after years of starts, stops, and course corrections; after budgetary underfunding and interventions by agencies outside those primarily responsible for the program (think Congress or the Federal Communications Commission); after long policy battles and unrealized mandates, after years of blood, sweat, and tears spent in wrestling a comprehensive and stable enterprise out of the competing motives and goals of myriad players, after all this — GPS is on relatively solid ground with a relatively clear way ahead.

The 2017 National Defense Authorization Act, passed in December by the last bipartisan Congress that we’ll see for a couple of years, funds the program in most of its parts and provides guidance on issues of a backup system, frequency protection, critical infrastructures, and use of other GNSS systems by U.S. citizens and military services.

The International Committee on GNSS (ICG) continues to reconcile operational practices and technical policies to optimize the utility of multiple systems. Bilateral agreements are taking compatibility and interoperability even further.

If Congress puts our tax money where its mouth is and matches authorization with 2017 appropriations, then the GPS program will be in good shape — absent a U-turn when the bill arrives at the White House.

Indeed, the known knowns seem likely to outweigh the known unknowns. As for perhaps the leading unknown unknown, a new commander in chief, well, stay tuned to your SMS provider.

Omnibus legislation such as a $619-billion budget makes a tempting target for whim and vendetta, for superficial micro-managing.

Perhaps it will be enough to mention that Twitter ultimately depends on effective and stable GPS timing. (Yes, we can assert that caveat in far less than 140 characters.)

But, more likely, GPS/GNSS- stakeholders — within and outside government, in the United States and abroad, among users and providers — will need to stand ready to protect hard-won equities against caprice and transient temperament. A 44-year legacy and institution must necessarily trump the passing fancies or fantasies of term-limited politicians and administrations.

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A national unpopularity contest. Sort of Commedia dell’arte meets Monty Python, directed by Todd Phillips, with a cameo appearance by Berlusconi.

Did we find it risible? Oh, yes, but were those tears of laughter, sorrow, or disbelief?

So, while we are collectively unpacking the meaning and nonsense from two years of political theater and telling each other our fortunes for the next four, what does it portend for GNSS?

Well, the tea leaves are a little unclear.

American Election 2016 — now that was something, wasn’t it?

A national unpopularity contest. Sort of Commedia dell’arte meets Monty Python, directed by Todd Phillips, with a cameo appearance by Berlusconi.

Did we find it risible? Oh, yes, but were those tears of laughter, sorrow, or disbelief?

So, while we are collectively unpacking the meaning and nonsense from two years of political theater and telling each other our fortunes for the next four, what does it portend for GNSS?

Well, the tea leaves are a little unclear.

The Trump-l’oeil of the president-elect’s platform to date provides few clues, although Dee Ann Divis takes a valiant stab at the implications for GPS in this issue’s Washington View column.

But consider this: Another Republican showman, Phineas Taylor Barnum, a two-term state legislator and mayor of Bridgeport, Connecticut, actually appeared to be an anti-slavery advocate toward the end.

If P. T. Barnum — better known to later generations for his traveling circuses than his political acumen — could find nobility amid his gaudy business and personal style, we should not abandon all hope. Of course, Barnum probably never thought of running for president, but if he had, could we have intuited his stance on, say, the gold standard from the content of his menagerie?

If we were to elevate the theatrical aspects of the current situation to the Shakespearean level, we could consider The Winter’s Tale from which this column’s title is drawn. Recall how King Leontes of Sicily, in a sudden fit of insane jealousy, imprisons his wife. He then sends the ultimately unfortunate Antigonus to abandon Leontes’ daughter, Perdita, whom the king thinks was sired by his childhood friend, the Bohemian ruler Polixenes.

Various tragedies ensue.

By the fourth act, however, an amazing turn of events: Leontes, apparently restored to sanity through the suffering of his family and nation, frees his wife. He attends a popular festival in disguise, discovers the simple condition of common folk, and ultimately reconciles himself with Polixenes.

As metaphor of our current situation, we can hope that The Winter’s Tale might point to the end of the inutile prosecution of and threats of jail for Hillary Clinton and that the Trump era will not, as feared, worsen the inequitable distribution of wealth in society. Perhaps even that, along the way, a riven nation will find a renewed comity.

But enough of theater as politics. How about politics as politics?

Come 2017, for the first time since the second Bush administration, Republicans will have seized control of all three branches of the U.S. government. One mixed-blessing president exits the stage; another enters devoid of a majority in the popular vote. But as with George W., the Donald’s wings will probably remain unclipped despite the absence of a mandate.

Nonetheless, we should recall that it was the Bush government in 2004 that issued a (still unfulfilled) presidential directive on GPS/PNT. And another is arguably past due.

So, here’s what I think: since the 18th century, news media have often been called the Fourth Estate, implying that journalists have a seat at the table of the nation’s governance. (Of course, the election may have also underscored the passing of that notion and the rise of social media in its stead.)

But we actually have long had another de facto branch of government: the oft-maligned leaders and staff of the federal departments, agencies, and commissions. Yes, the dreaded bureaucrats — in whom resides the institutional memory of programs, policies, and practice. And therein exists a constructive inertia, the part of Newton’s First Law that asserts a body in motion will remain so absent other external forces.

Four decades into the GPS era, myriad GNSS-related initiatives — domestic and international, public and private — are under way. Every person with a cell phone getting into a car with a navigation system is a beneficiary and implicit advocate of the technology. GNSS has become an irresistible force over which the influence of any one person can only be limited, whether for good ends or poor.

For which we should be thankful.

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Play a different game, move the goalposts, change the rules.

For several years now, a series of would-be wireless broadband service providers have been attempting to convince the Federal Communications Commission (FCC) to repurpose radio frequency spectrum near the GPS L1 band.

Past efforts have failed because of the transmissions’ demonstrated harmful effects on GPS and other GNSS signals. Now a new contender is trying to gain FCC’s approval by changing the way that those effects are measured.

How do you win when you are really losing?

Play a different game, move the goalposts, change the rules.

For several years now, a series of would-be wireless broadband service providers have been attempting to convince the Federal Communications Commission (FCC) to repurpose radio frequency spectrum near the GPS L1 band.

Past efforts have failed because of the transmissions’ demonstrated harmful effects on GPS and other GNSS signals. Now a new contender is trying to gain FCC’s approval by changing the way that those effects are measured.

Ligado Networks, which arose from the ashes of LightSquared, is proposing a new round of tests to demonstrate that a revised spectrum plan will allow its terrestrial transmissions to coexist with GNSS. Several years ago LightSquared failed to gain FCC approval after extensive tests of its original proposal, overseen by the broadband company and the GPS industry, revealed serious and widespread interference to GNSS receivers.

Ligado has altered its request to the FCC, offering to abandon the 1545–1555 MHz downlink band closest to GPS and other GNSS services at L1. That would leave it with the more distant 1526–1536 MHz band. The company says it would also reduce the effective isotropically radiated power (EIRP) limit for this band from 42 dBW to 32 dBW.

This proposal won the support of some key GNSS equipment manufacturers, as long as Ligado can demonstrate that its transmissions in the lower 10-megahertz band will not harm GNSS signals.

That’s where Ligado has begun trying to change the rules of how harmful effects are measured and to find a more sympathetic venue for their tests.

The traditional metric for measuring an unacceptable change in GNSS signal quality — and other communications, navigation, timing and radar systems — is a decibel or less reduction in the carrier-to-noise power density ratio (C/N₀). That, indeed, is the path that the Department of Transportation (DoT) is following with its GPS Adjacent Band Compatibility (ABC) Assessment. Ligado, however, is proposing instead that its signals must show a measurable negative effect on positioning accuracy.

Taken out of context — historical, physical, operational — Ligado’s proposal might seem logical, even practical. GNSS is a positioning technology. If the positioning quality is unaffected, there shouldn’t be a problem. No harm, no foul, right?

Besides, carrier-to-noise power density ratio sounds abstract, theoretical, nerdy. Not the sort of measure that appeals to Americans’ pragmatic minds. Anyway, what’s a measly decibel among friends and neighbors?

Meanwhile, much as lawyers sometimes “shop around” for sympathetic judges to hear their cases, Ligado has been seeking a forum that will produce the results it wants and needs to sell its proposal to FCC commissioners — and perhaps to Congress to which the FCC reports.

That’s when Ligado discovered the National Advanced Spectrum and Communications Test Network (NASCTN), a national network of federal, academic, and commercial test facilities formed in 2015. Despite characterizing itself as a “neutral forum,” NASCTN’s acknowledges that part of its mission is to “accelerate the deployment of wireless technologies among commercial and federal users.”

In any case, it is the Ligado/NASCTN “measurand” of position accuracy that is impractical. The reality of the GNSS equipment marketplace is that there are hundreds, even thousands, of different types of receivers, each with its own hardware and software design, distinct algorithms for processing signals, and various intended applications. And neither Ligado nor NACTN propose to track them all down and measure their susceptibility to transmissions based on Ligado’s new spectrum plan.

Rather than trying to evaluate the variable effects on different types of user equipment, the traditional metric of measuring the RF source’s effect on C/N₀ provides a consistent, quantifiable, and practical method for evaluating the technologies.

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But then the best-laid plans. . . .

So, if everything had gone as planned, we would have a new ground control segment (OCX) operating a new generation of satellites (GPS III) as they launch into an expanded constellation in support of modernized military GPS user equipment (MGUE).

But then the best-laid plans. . . .

OCX still appears four to five years away, the first tranche of GPS IIIs are going up years late, and, as a 2015 Government Accountability Office report concluded, MGUE’s acquisition strategy has been revised several times in the Air Force’s quest to develop the new user equipment.

How bad is the situation? Well, so bad that the House Armed Services Committee recently zeroed out Fiscal Year 2017 funding for OCX because of the cost overruns and schedule slippage.

“Re-baselining,” a term of bureaucratic art that in other quarters is known as moving the goalposts, has become a way of life for GPS. The program is always on schedule, because the schedule is always new and improved. What continual re-baselining hides, however, is that the GPS program, at 42 years of age, is suffering from a kind of mid-life crisis.

How did it come to this? A few of the culprits:

• Changes in leadership. As ambitious and talented military leaders climb the GPS Directorate or Air Force Space Command rungs of their careers, the typical three-year tour of duty at Los Angeles Air Force Base means a constant cycle of re-education. The GPS program has been good for upwardly mobile officers, as many colonels turned into generals, aided in part by overseeing an ever-more-popular utility. But it comes with an overhead of training costs.

• Design decisions, technical challenges, and engineering changes. Keeping the heavy, power-draining Nuclear Detection System on board GPS satellites, adding multiple new signals, devising a digital signal processor, implementing inter-satellite links.

• Loss of expertise. A few years back, Air Force dropped a contractor, Arinc, Inc., which had advised the program office for decades, in favor of a vendor with limited GPS expertise. That reset the learning curve while the newbies got up to speed.

Another example: Along with the technical challenges, the folks responsible for designing and building every GPS satellite navigation payload suffered a steady erosion of engineering talent as ITT Industries was absorbed by Exelis and then Harris Corporation. The associated delays rippled through the whole GPS III endeavor.

It also didn’t help that a couple of years ago the Air Force cashiered its GPS Independent Review Team, a group of experienced outside advisers authorized to take the long view. A couple of bright spots in this gloomy picture are the Aerospace Corporation and the Massachusetts branch of the MITRE Corporation. These federally funded research and development centers provide institutional memory along with day-to-day expertise in solving technical and programmatic problems.

• Budgetary processes. GLONASS gets its own line item in the Russian federal budget. Europe’s Galileo has funding for seven years. China has five-year plans that place its BeiDou Navigation Satellite System high on the list for resource allocation.

But GPS? Rescissions, congressional hearings, new demands, GAO reviews take place from month to month, week to week, even day to day. A situation that is made worse by the Air Force’s ability to reprogram funds from GPS to the squeaky wheel or problem child or favored program of the moment.

What can be done? Well, maybe it’s time to re-baseline the whole deal.

Obviously this can’t be done by the folks holding things together in current operations, acquisitions, engineering, and system management. No one wants to rebuild a car while it’s flying down the freeway at 70 miles an hour.

Perhaps the program needs to rebuild its brain trust, establish a parallel organization that can take a longer view beyond budget cycles, leadership rotations, and engineering change orders.

Back in the 1990s, such an effort was undertaken by a blue-ribbon group supported by the National Research Council. Today, the National Space-Based PNT Advisory Board might be best positioned for such a mission.

No one wants to make any sudden moves with a resource on which industries, critical infrastructures, and nations depend. But some kind of movement is definitely needed — and soon.

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