WASHINGTON VIEW
hough the United States has Sir Mark Walport, the U.K.’s Gov- been working on a backup for ernment Chief Scientific Adviser, is GPS for years, and was actu- conducting the review, which should be ally close to completing an completed by the end of this year, several Tequipment update to that end in 2009, sources, told Inside GNSS. All of those Europe may be the first to put in place who described the work asked for ano- a fully independent alternative for posi- nymity to be able to discuss it freely. tioning and timing data — an economic The Blackett team is looking at how insurance policy against satellite naviga- dependent critical services are on GNSS tion signals being jammed or disrupted. and, therefore, how vulnerable they Led by the United Kingdom, the would be to GNSS disruption. The study Europeans are weighing how to deal springs from an earlier Blackett Review which recommended looking more closely at timing data, a course of work that was later expanded to include posi- EU eLoran Efforts Sharpen tion and navigation. The review will incorporate the while U.S. Requirements Study results of a separate but related study looking at the fiscal consequences of a GNSS disruption in the U.K. Continues “It just looks squarely at the economic impacts,” said one of the experts. DEE ANN DIVIS with the vulnerabilities created by rely- Together, said one of the sources, the ing solely on signals from GNSS. As in two studies will give a well-rounded view the U.S. their options include recycling of the PNT-related economic and techni- their old Loran C navigation sites to sup- cal challenges faced by the U.K. includ- port an enhanced Loran (eLoran) service ing critical infrastructure dependencies. as a backup for GPS and Galileo. Perhaps more importantly, they will also “There is a very increased focus on look at possible solutions. GNSS resiliency at the moment,” said an The Blackett Review will include rec- expert familiar with the issue. “A num- ommendations, the source said, which ber of countries in Europe are working could range from doing additional stud- towards PNT (position, navigation and ies or developing a strategy to boosting timing) strategies,” the source said, add- funding in a particular area. The recom- ing that “there’s a lot of discussion about mendations are quite high level, they PNT in the round — not just GNSS.” said, but carry a lot of weight. The European Commission (EC) is “The recommendations are effectively funding a study in support of a Europe- from the government’s chief science an radionavigation plan, said the source, adviser,” the source explained. “That is a and that study discusses the need for very powerful person to stand up and say resilient PNT and looks at using terres- we need to do this or we need to do that.” trial systems as well as space-based sig- The format of the Blackett Review nals. The European Space Agency is also may be especially useful. It is a type of Dee Ann Divis has covered taking a broader perspective in its new study that follows a set process of analy- GNSS and the aerospace navigation program, describing its new sis and presentation aimed at supporting industry since the early endeavor as a PNT effort, not a GNSS government policymakers. 1990s, writing for Jane’s one, and putting a strong emphasis on “Awareness of the vulnerability of International Defense hybrid systems, said the expert. GPS, and of GNSS grows stronger,” said Review, the Los Angeles Times, AeroSpace Daily and another source. “It’s almost complete other publications. She was the science and technology U.K. Initiatives amongst engineers but the difficulty is editor at United Press International for five years, leaving for a year to attend the Massachusetts Institute Feeding into those broad European that it’s only patchy amongst politicians.” of Technology as a Knight Science Journalism Fellow. efforts are two PNT-focused studies in Depending on the findings the U.K. the U.K., including a Blackett Review at may move quickly to implement some of the highest levels. those solutions, an expert said. One of
22 InsideGNSS MAY/JUNE 2017 www.insidegnss.com WASHINGTON VIEW
the options that could be suggested is the (though one source expressed concern ed States, efforts to set up a GPS backup implementation of eLoran — though that one had been shut down) and Norway remain mired in studies. is not a course of action Great Britain can has three. Norway did have four sites, but The U.S. is now roughly a year and a undertake on its own. dropped its northernmost station. half into an effort to establish require- With the exception of that one Nor- ments for a GPS backup system. This Dry and Warm wegian site, Schue said he believed the followed an extensive research effort The eLoran system, which the Brit- European Loran stations were being kept in 2014, which was itself a follow-up to ish have been demonstrating at their “dry and warm” — that is they are gener- a three-year study completed roughly Anthorn site, sends out powerful, low- ally not operating but the power was still seven years earlier. frequency signals using terrestrial trans- on. The Germans have repurposed their According to a Dec. 7, 2016 presen- mitters that do not have the same vulner- site for another kind of service but not tation by Jim Platt, the director of the abilities as space-based systems to space one that would conflict with eLoran, said Department of Homeland Security’s weather or future on-orbit conflicts. Schue, so a multi-purpose broadcast site PNT Office, to the National Space-Based The system is widely considered to be a remains possible. PNT Advisory Board, the validation of promising backup for GPS, particularly The U.K. has taken a collaborative the timing requirements for critical for timing data. approach in addressing eLoran’s poten- infrastructure should be completed by “It’s delivering, certainly, a microsec- tial, Schue told Inside GNSS. The U.K. September. ond,” said David Last, a radionavigation hosted a meeting attended by the other Meeting the end-of-year deadline for expert following the Anthorn tests. “We Loran-equipped nations and potential the comprehensive and extensive report are aiming for 100 nanoseconds service eLoran users. The British are working now being developed will be difficult, in due course and that will require a dif- with these countries to see if they can get said Dana Goward, the president of the ferential operation — but the substan- back to where they were with the North- Resilient Navigation and Timing Foun- tial market is for a microsecond at the ern European Loran system, Schue said, dation. “And then I imagine after that moment.” to provide “at least timing and frequen- they’re going to have to do an analysis “eLoran has a very stable frequency cy backup across their various coverage of alternatives, which I’m expecting is output, a frequency available because areas and possibly even positioning, going to be nearly a repeat of what has it’s based on three atomic clocks on the depending on which nations and stations been done before. They look at all the stations just like GPS has three atomic want to play.” available technologies and compare them clocks in the satellite,” added Charles Though the U.K. work seems to against each other and see which is the “Chuck” Schue, the co-founder, presi- be moving smoothly there have been best compliment and backup system dent and CEO of UrsaNav, which provides notable, nontechnical disruptions. It for GPS. My guess is ...they will prob- eLoran technology. UrsaNav has been is unclear, for example, how the U.K.’s ably again find that eLoran is the best, working with the Harris Corp. and the exit from the European Union (EU) if not the only, wide area compliment U.S. government through a Cooperative will impact future cooperation and the and backup system that is available. But Research And Development Agreement rules of the June 8 U.K. election, which that’s something that they have to grind (CRADA) to test eLoran as a wide-area was still on the horizon at press time, through and all of that grinding through timing source in the United States. Schue required that British officials not make is going to take some time I’m sure.” is also a co-owner of Taviga with Charles decisions, release study results or speak Though the technology has not Curry of Chronos Technology Ltd. Taviga publicly. On top of that, should the U.K. improved or changed significantly since supports low frequency PNT in Europe government change hands there also earlier studies, Goward said the people including eLoran.
24 InsideGNSS MAY/JUNE 2017 www.insidegnss.com WASHINGTON VIEW
a backup for GPS in the United States. ly completed, DHS wanted to move the org/2017/05/21/why-congress-is-inter- Among other things the new system Coast Guard —which was and is respon- ested-in-gps-vulnerability-eloran/> would have to be wireless, terrestrial, sible for Loran — to the National Protec- Though Congress eventually ordered synchronized with coordinated universal tion and Programs Directorate or NPPD, the sites preserved pending a final eLoran time, and able to penetrate underground which was in charge of infrastructure decision, the lawmakers were too slow to and inside buildings — all characteristics protection, according to Goward. The save the infrastructure. The Coast Guard of eLoran. transfer was stalled, however, because was ordered to dismantle the sites and Introduced by Duncan Hunter, DHS put the enacting language in its didn’t have the funding to do otherwise. R-Calif., an established supporter of budget proposal and Congress failed They efficiently emptied the majority of eLoran, bill H.R. 2518 would require the to get it passed, resorting to a continu- the 25 sites, largely flushing the $160 mil- Department of Transportation secretary ing resolution instead. The program lion in upgrades in the process. to deliver a plan to lawmakers to estab- was then cut on the recommendation It wasn’t their fault, said Schue. “They lish such a system within three years — of the Office of Management and Bud- did the best they could.” “subject to the availability of appropria- get, which made a last minute change to Now, said Schue, “there’s only eight tions.” President Obama’s first budget to show- sites in the contiguous U.S. that still have That’s quite a proviso given that it’s case the White House’s ability to find antennas up and then at all the other sites been a lack of appropriations that has savings. Despite loud protests the money the antennas are down both here in the been holding up deployment of eLoran for Loran C stayed cut, effectively kill- U.S. and in Canada. Canada followed in the U.S. for years. ing eLoran in the process. Promises to our lead and took their towers down. At A plan to deploy eLoran, the culmi- restore the program were never fulfilled, most of the stations the technology has nation of that three-year study, was first according to Goward. been taken out and disposed of including announced in 2008 by the Department A more detailed summary of what in some cases the generators, you know of Homeland Security. With some $160 happened can be found on the Foun- transformers, air conditioners — those million in upgrades to the old sites near- dation’s website. Navigation jamming and spoofing threats are growing. Be ready. HIGH-ASSURANCE PNT Adversaries jam and spoof GPS signals at will. Seize the advantage with Rockwell Collins’ satellite navigation, PNT and augmentation solutions. Our advanced, proven and reliable solutions are ready for any mission requiring fail-safe performance, military or commercial. Visit us at JNC, booth 208. © 2017 Rockwell Collins. All rights reserved. rockwellcollins.com 26 InsideGNSS MAY/JUNE 2017 www.insidegnss.com New eLoran Standards There is one bright spot amidst the tangle of delays and equip- IMU ment loss — the launch of a new, formal development process for international eLoran standards. TACTICAL GRADE Loran C never had a classic set of standards to govern the development of receivers and other equipment; it operated under an instruction from the Commandant of the Coast Guard. SAE International, a professional association and stan- dards development organization with over 127,000 members worldwide, has elected to change that. The SAE Aerospace Council is taking on standards devel- opment for eLoran equipment as part of the work of a new committee devoted to position, navigation and timing stan- dards. Committee AS-5, which is under the Aerospace Avionic Systems Group chaired by Bill Woodward, met for the first time in May. The group did two things at its inaugural meeting, said 1:1 scale Woodward, who works for the Virginia firm Geodesicx. It took the commandant’s instruction and converted it into a Word document for publication as an SAE standard. “That’s not going to change,” he said, “It’s just going to say that now there is a standard for what we used to call Loran C.” They also launched work on an Interface Control Document STIM300 is a tactical grade Inertial for eLoran. This contains the kind information necessary to Measurement Unit, IMU, for demanding build transmitters and receivers and Woodward said he hoped to have it published in 90 days — that is by roughly the end of guidance and navigation applications. August. In addition, the committee is writing an AIR or Aero- space Information Report on eLoran, which aims to address any misperceptions by publishing accurate information and • ITAR free thereby creating a common foundation for discussion. • Small size, low weight, power and cost According to AS-5’s Work In Progress list there are another • Insensitive to magnetic fi elds three other documents under development — so it’s no surprise • Low gyro bias instability (0.3°/h) that Woodward is looking for technical experts to join the com- • Low gyro noise (0.15°/√h) mittee. [email protected] • www.sensonor.com www.insidegnss.com MAY/JUNE 2017 InsideGNSS 27