Instructions on submitting your abstract can be found at www.ion.org/ptti

PTTI is an annual conference sponsored by ION with a technical program designed to disseminate and coordinate PTTI information at the user level, review present and future PTTI requirements, inform government and industry engineers, technicians, and managers of precise time and frequency technology and its problems, and provide an opportunity for an active exchange of new technology associated with PTTI.

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Described in the April 28 issue of Nature Photonics, the demonstration shows how next-generation atomic clocks at different locations could be linked wirelessly to improve geodesy (altitude mapping), distribution of time and frequency information, satellite navigation, radar arrays and other applications. Clock signals of this type have previously been transferred by fiber-optic cable, but a wireless channel offers greater flexibility and the eventual possibility of transfer to and from satellites.

NIST researchers transferred ultraprecise time signals over the air between a laboratory on NIST’s campus in Boulder, Colorado, and nearby Kohler Mesa. Signals were sent in both directions, reflected off a mirror on the mesa, and returned to the lab, a total distrance of approximately two kilometers. The two-way technique overcomes timing distortions on the signals from turbulence in the atmosphere, and shows how next-generation atomic clocks at different locations could be linked wirelessly to improve distribution of time and frequency information and other applications.

The stability of the transferred infrared signal matched that of NIST’s best experimental atomic clock, which operates at optical frequencies. Infrared light is very close to the frequencies used by these clocks, and both are much higher than the microwave frequencies in conventional atomic clocks currently used as national time standards. Operating frequency is one of the most important factors in the precision of optical atomic clocks, which have the potential to provide a 100-fold improvement in the accuracy of future time standards. But the signals need to be distributed with minimal loss of precision and accuracy.

The signal transfer demonstration was performed outdoors over a two-way wireless link using two laser frequency combs. A frequency comb generates a steady stream of ultrashort optical pulses with a spacing that can be synchronized perfectly with the “ticks” of an optical atomic clock. (Click here for more on how frequency combs work.) In the experiment, the two combs were synchronized to the same stable optical cavity, which serves as a stand-in for an optical atomic clock. Each comb pulse was sent from one of two locations on NIST’s campus in Boulder, Colorado, reflected off a mirror on a mesa behind the campus, and returned to the other site, traveling a total distance of two kilometers.

Researchers measured travel times for pulses traveling in opposite directions between the two sites. The cumulative timing differences and frequency instabilities were infinitesimal, just one million-billionths of a second per hour, a performance level sufficient for transferring optical clock signals.

The transfer technique overcomes typical wireless signal problems such as turbulence in the atmosphere—the phenomenon that makes images shimmer when it’s very hot outside. Because turbulence affects both directions equally, it can be cancelled out. The transfer technique can also withstand signal losses due to temporary obstruction of the light path. The method should be able to operate at much longer distances, possibly even over future ground-to-satellite optical communication links as an added timing channel, researchers say.

The combs potentially could be made portable, and the low-power infrared light is safe for eyes. The research is funded in part by the Defense Advanced Research Projects Agency.

“A billionth of a second equals a nanosecond, a time interval far beyond our own human capacity of appreciation,” explains Marco Falcone, ESA’s Galileo System Manager.

The prediction error for the offset between Galileo System Time and UTC, expressed in nanoseconds. The UTC value available to the user via Galileo is expected to be accurate within 26 nanoseconds, but in spring 2013 it has been even better, with a prediction error in the last two months of less than five nanoseconds.

“A single lightning flash across the sky during a thunderstorm lasts about ten milliseconds, which is already 10 000 000 nanoseconds. But for high-tech applications, as well as navigation services, nanosecond accuracy is essential.”

The replacement for Greenwich Mean Time, UTC is part of all our daily lives: it is the timing used for Internet, banking and aviation standards as well as precise scientific experiments, maintained by the Paris-based Bureau International de Poids et Mesures (BIPM).

The BIPM computes UTC based on inputs from collections of atomic clocks maintained by institutions around the world, including ESA’s ESTEC technical centre in Noordwijk, the Netherlands.

‘Galileo time’ is derived independently of UTC but is being kept close to it, with a precise ‘offset’ between the two values being calculated continuously and then disseminated through Galileo’s navigation message.

Galileo, like all other satellite navigation systems, is based on the highly precise measurement of time. A receiver on the ground pinpoints its position by calculating how long signals from satellites in orbit take to reach it.

Matching the receiver and satellite clocks then multiplying the time taken by the speed of light gives the range between user and satellite, allowing the receiver to fix its own location relative to four or more satellites.

“Each navigation system has its internal reference system time used to synchronise all system clocks and maintain overall coherence,” adds Marco.

Galileo’s navigation message embedded in its signals include precise timings based on Galileo System Time, kept close to global time standard UTC with a precise offset given, accurate to at least 26 nanoseconds.

INRIM has been supporting ESA’s Galileo development since the early phases of the project. More recently INRIM has overseen the creation of a ‘Time Validation Facility’ for Galileo in collaboration with five other European time-measurement institutions: the Physikalisch Technische Bundesanstalt in Germany, the National Physics Laboratory in the UK, the Systeme de References Temps Espace/Observatoire de Paris in France, the Real Instituto y Observatorio de la Armada in Spain and Observatoire Royale de Belgique.

Galileo’s Ground Control Segment (GCS) in the Fucino Control Centre in Italy oversees Galileo navigation services and satellite payload operations.

Each day, the most precise European clocks and national time scales are compared to GST and the offset compared to UTC is estimated and provided to the Galileo Control Centre. This offset is then uploaded to the Galileo satellites for transmission in the navigation message available to users.

As explained by Patrizia Tavella from INRIM, “The UTC value available to the user via Galileo is expected to be accurate within 26 nanoseconds, but in the last two months it was even better, with a prediction error in the last two months of less than five nanoseconds.”

I mentioned at the time how incredulous I was at the question, but that I answered it with a straight face. Now, while professional courtesy prevents me from ever revealing the name of the female journalist, I will say that she evidently started an uncomfortable trend. Much of my correspondence lately has concerned the connections between time and position and/or navigation and why we are so concerned about time.

I won’t bore my more sophisticated readers with GPS 101, or certainly not Time and Frequency Metrology 101, but I will tell you that I think we (this is not the royal “we” but includes all of us who work with and promote GPS on a daily basis) need to do a better job describing just how GPS works and more importantly how critical precise time and frequency is to position and navigation solutions, whether GPS is utilized or not. And I don’t have the time here to take up the argument concerning how important GPS is to our critical national infrastructure. Indeed, a topic and column for another time.

I am sure my time and frequency metrology friends and colleagues at NIST (National Institute of Standards and Technology in Boulder, Colorado) and USNO (U.S. Naval Observatory — read as UTC — home of Coordinated Universal Time and the Master Clock) would probably go about this differently. They tend to approach these problems strictly from a metrology viewpoint. While there is nothing wrong with that perspective, I hope to give you a more hands-on operational view of time and how it relates to position and navigation.

Smithsonian Institution and Time Exhibit

An operational backup of a Transit 5-A satellite.

Of course, I could take the easy way out and advise all my readers to visit the latest Smithsonian time exhibit entitled: Time and Navigation – The Untold Story of Getting From Here to There. The new exhibit opens in April.

Here are a few quick Smithsonian facts, with commentary added, for those who want to visit and learn just what time has to do with GPS and navigation in general:

What: The Relationship Between Time and Navigation

When: Opens in April 2013.

Where: The Smithsonian’s National Air and Space Museum, Independence Avenue at Sixth Street, S.W., Washington, D.C.

Responsibility: “Time and Navigation — The Untold Story of Getting From Here to There” is being produced jointly by the Smithsonian’s National Air and Space Museum and the National Museum of American History. This is one of the few times, if not the first, that two museums have jointly produced a major exhibit of this importance.

Sponsors: The exhibition is made possible through the generous contributions of Northrop Grumman; Exelis Inc.; Honeywell; National Geospatial-Intelligence Agency; U.S. Department of Transportation; Magellan; National Coordination Office for Space-Based Positioning, Navigation and Timing; Rockwell Collins; and ION the Institute of Navigation. Note: The sponsors are listed in order of the amount they gave to present the exhibition, but it should be noted that ION was among the first contributors, making the museums’ decision to go ahead with the exhibit a more comfortable one. More on that and why it is significant later.

The USS Alabama.

Artifacts: (Don’t you just love the word artifact? Indeed, someone once told me, and not unkindly, that I resemble that word.) The time exhibition features 144 artifacts, drawn primarily from the collections of the participating museums. Highlights of the exhibition include a representation of a 19th-century ship from the U.S. Exploring Expedition; the first sea-going marine chronometer made in the United States; the submarine navigation system for the USS Alabama; a TRANSIT navigation satellite (a major naval predecessor to GPS); Wiley Post’s airplane, the Winnie Mae; and Stanley, originally from the Stanford University Racing Team and written about many times by yours truly in GPS World. Stanley is a robotic vehicle that can drive itself. Stanley is a 2005 Volkswagen Touareg, which has been considerably modified to navigate without remote control and without a human driver onboard. Stanley handily won the 2005 DARPA Grand Challenge (Defense Advanced Research Projects Agency), a robotic vehicle race. Stanley successfully navigated 212 kilometers (132 miles) across desert terrain and has had his (here we go, anthropomorphizing automobiles) own robotic exhibit at the Smithsonian since 2009.

An official DARPA photograph of Stanley at the 2005 DARPA Grand Challenge. Stanley, created by the Stanford University Racing Team, won the race.

Organization: The current time exhibition is organized into five sections: Navigation for Everyone; Navigating at Sea; Navigating in the Air; Navigating in Space; and Inventing Satellite Navigation.

Theme: If you want to know where you are, you need an accurate clock. In other words, you need to know when you are. About 250 years ago, sailors first used accurate clocks, later known as chronometers, to navigate the oceans. Today, we locate ourselves on the globe with synchronized atomic clocks in orbiting satellites (GPS is the primary method today). Among the many challenges facing navigation from then to now, one stands out: keeping accurate time.

For centuries, nations have invested enormous resources to determine time and place for geopolitical reasons, and their research has changed people’s view of the world. Advanced technology that was once available only to the military has become commonplace and downloadable to cell phones, iPADS and computers. Instead of unfolding a map or stopping at a gas station to ask for directions, drivers can now consult their car’s GPS (Global Positioning) system. The new gallery examines the cultural and technological history of precise timekeeping and navigation at sea, in the air, and in space and the impact of satellite navigation on our everyday lives. Which of course are also the missions of the Institute of Navigation and GPS World magazine.

When Am I?

Many of you have heard the old saw about those who don’t know history being doomed to repeat it, and if you don’t know where you have been, how can you know where you are? There are probably numerous maxims that fit the bill when it comes to the history of time and navigation, and the Smithsonian Exhibit certainly does a great job of hitting all the high points, but beyond that, they will take you into about as much detail as you can stand. If possible, plan on attending the exhibit several times and delving into each of the five major themes. But if you can’t visit Washington, D.C., and the Smithsonian exhibit, then visit virtually on their excellent website.

For our purposes, suffice it to say that you can’t really know where you are unless you know when you are. That requires a clock, the more precise the better, and consequently the more accurate your position.

History Lesson

More than 200 years ago, sailors sailing between Europe and the New World knew where they were only in relationship to their latitude, but had no idea other than dead reckoning of their longitude.

Enter Boston clockmaker William Cranch Bond who, although he was not the first, constructed a specialized timepiece, which later became known as the Bond Chronometer, which sailors used to determine longitude at sea. But still there were problems. Sailors used a maritime sextant and chronometer to determine position, but both devices depended on the other. On cloudy or foggy days, either the horizon or the sun and stars or both were unavailable, and positioning/navigation was relegated to, in all seriousness, dead reckoning with a dubious magnetic compass, a rock and a rope. The problem being, of course, that dead reckoning made many mariners resemble the first word in that very unfortunate navigational phrase.

Time and Air Navigation

Fast forward almost a century (1903), and aeroplanes are now on the scene along with all the problems attendant in navigating a machine easily traveling ten times faster than most ships. But of course the U.S. Navy rationalized that if a watch and a sextant were good enough for navigating maritime ships, then they were good enough for ships of the air — even if the horizon was often obscured or moved around a great deal, or turbulence made balancing a sextant difficult.

The result was most aviators gave up on the sextant, especially solo aviators, and just used a watch and, you guessed it, dead reckoning, which is exactly what happened to many aviators in 1927 who attempted to win the Raymond Orteig $25,000 prize for being the first solo aviator to cross the Atlantic nonstop from the East Coast of the U.S. — in fact, it had to be New York to Paris, France. For you trivia buffs, it had to be New York to Paris because the person offering the prize, Monsieur Raymond Ortieg, was an emigrant from France who did well for himself and went from a penniless restaurant busboy to owning two of the most prestigious hotels in New York City at the time. Hence the connection between New York and Paris. But I digress.

Charles Lindbergh (left) and Raymond Orteig.

Enter Lindbergh

As most of you are aware, then captain, later colonel, Charles Lindbergh took up that dare and won the Orteig-prize on the 21 of May, 1927, when he landed in Paris after a grueling 33½-hour solo flight across the Atlantic. When Lindbergh hit land after being “feet wet” for more than 30 hours and 3500+ miles, he was less than three miles from his intended European entry point, a feat that would be hard to duplicate today without GPS, as even with an unaided inertial system the drift can sometimes be as high as one kilometer per hour.

One part I always find amusing about the Lindbergh transatlantic saga is that after flying with “dead reckoning” as his only means of navigation for 30 hours across the Atlantic, he followed the Seine river all the way to Paris, so he essentially converted from VFR (Visual Flight Rules) to the IFR or “I fly rivers” navigation method for the last part of his journey.

Meteorologists and the sealed barometric equipment Lindbergh carried on board — to prove he never landed enroute or that it was indeed a non-stop flight — would not only verify that fact but also verify that he navigated the Atlantic in what we might call today The Perfect Calm. Indeed, Lucky Lindy picked the perfect 48-hour period for his flight. For those of you who read the book, saw the movie, or were there, will remember that in New York the weather during the night preceding his historic takeoff from the dirt-churned-into-mud runway at Roosevelt Field, Long Island, New York, was less than cooperative. There was a major thunderstorm with lots of lightning and several inches of rain; consequently, many counseled Captain Lindbergh to postpone his flight. But he would have none of it and the rest is history.

The most interesting part of the story, however, is that the entire flight was accomplished with “dead reckoning,” a compass and a watch, the very same tools that Captain Lindbergh used during his tenure as a U.S. Mail pilot. So, in fact, Lucky Lindy actually knew very little about navigating an airplane or avigation, as many called it at the time. Indeed, according to Roger Connor from the National Air and Space Museum and his wonderful article in this month’s Smithsonian Air & Space magazine, Even Lindbergh Got Lost, Captain Lindbergh did not learn to properly navigate with a sextant, chronometer and star charts until more than a year after his famous flight to Paris.

I won’t spoil the story for you, but he learned to navigate as did his famous wife, Ann Morrow Lindbergh, from then Lieutenant Commander Philip V.H. Weems of the U.S. Navy. LCDR Weems set up the nation’s first independent navigation school, and went on to instruct such notables as General Curtis LeMay, the Commander of Strategic Air Command (SAC), who went on to serve as the Chief of Staff of the USAF. Most people are not aware, but General LeMay was dual-qualified as a pilot and a navigator in the USAF. As the Commander in Chief of SAC or CINCSAC, he mandated that all SAC flight crews be able to navigate from Point A to Point B using only passive means that were always available and did not involve transmitting a signal outside the aircraft. In other words, celestial navigation, using a sextant, chronometer, special plotter and star charts, much as was taught by LCDR Weems.

I was one of the lucky SAC flight crew members who learned to navigate with those basic instruments. And checking my logbooks, I find that I made just short of 200 flights (99 round-trips) across the big pond, the Pacific that is, using those basic instruments. I mentioned this to a group of USAF aircrews recently during a speech, and when I asked how many of them could accomplish that feat if required to do so today, I was informed that sextants are no longer carried on USAF aircraft and most do not even have sextant ports. In other words, it is a lost art among flight crews today, and it is a shame, but it is also a topic for another time.

The important fact concerning navigation and time is that time — indeed, precise time — is and always has been critical to accurate navigation, especially aircraft navigation, no matter whether you are flying from New York to Paris, Texas, or New York to Paris, France. And GPS Atomic Reference Systems (Atomic Clocks) on orbit today, which deliver time accurate to millionths of a second, are even more critical since they are the heart of the system. So I would say to my journalist enquirer, GPS and atomic clocks are one and the same. You can’t navigate accurately without precise time.

Weems Legacy

Now, to bring this full circle, I first heard about the proposed Smithsonian Time Exhibit about two years ago from a friend and professional colleague, James Doherty, Captain, USCG retired. Jim, who once served as the Commander of the United States Coast Guard Navigation Center, is a past President of ION (Institute of Navigation), one of the few U.S. members of the Royal Institute of Navigation (RIN) in London, England, and now serves as the Chairman of the newly created Military Division at ION. And for full disclosure purposes, I must say that I have been a proud member of ION for more than 30 years.

Jim, who was serving on a Smithsonian panel as a subject-matter expert on navigation, told me that the Smithsonian had the idea for the time exhibit, but was looking for support, and the first organization to pledge support was indeed ION. The Institute of Navigation certainly does not have the deep pockets of Northrop and Exelis or the other major sponsors, but they are very serious about navigation and they are always looking for ways to promote their vision. This was the perfect opportunity.

And just in case you were wondering, the legacy that Captain, U.S. Navy, V.H. Weems left the world is a method of celestial navigation that persisted as the primary means, especially in the U.S. military and military forces around the world, for more than 60 years and is still the only reliable means of navigation available to us when everything else goes away. For with the Weems Method, as long as you have a sextant and an accurate clock, you can navigate anywhere.

Oh, and one other legacy: Captain V.H. Weems was the founder of the Institute of Navigation, which is the leading society devoted to the advancement of navigation in the world today. And for you trivia fans, the ION predates the RIN by two years.

Sequestration and Cancellations

Normally I would wrap it up here and say grab your sextant and happy navigating, but just as I wrap this up I have been told by informed sources at SMC and AFCEA that the GPS Partnership Council scheduled for May this year has been postponed. Sources at ION tell me that ION/JNC in Orlando has been cancelled for this year due to the restrictions on travel for U.S. government and military officials. In other words, more victims of sequestration and a Congress that can’t make the decisions we elect and pay them to make.

At ION they have always had the mantra, do it right or don’t bother doing it at all, and this year the travel restrictions are just too great. Certainly Jim Doherty and I were in the process of setting up another great Warrior Panel for the classified day, but that will have to wait for another time. However, I am assured by ION Executive Director Lisa Beaty that the ION GNSS meeting from September 16-20 at the Nashville Convention Center is definitely a go, so I look forward to seeing everyone there. Stop by the GPS World booth and say hello. Plus, I hope to see many of you at the 29th Annual National Space Symposium in Colorado Springs from April 8-11, 2013.

Until then, Happy Navigating – blow the dust off your sextant and give it a shot.

The replacement for Greenwich Mean Time, Coordinated Universal Time (UTC) is the timing used for Internet, banking, and aviation standards, and other international timescales, maintained by the Paris-based Bureau International de Poids et Mesures (BIPM).

Participating measurement institutes and observatories around the globe use collections of atomic clocks to estimate a current value for UTC. These clock data are fed through to the BIPM to be carefully weighted and averaged to derive a combined global value. The complexity of this effort is such that it takes around six weeks to arrive at a definitive final figure, ESA said.

Atomic clocks at ESTEC’s Navigation Laboratory. Once Galileo services start, ESA’s Navigation Lab will play an important role independently validating Galileo timing performance. Its atomic clocks, offering precise timings for ESA missions and experiments, are also contributing to the global setting of Coordinated Universal Time (UTC), the replacement for GMT.

ESTEC Director Franco Ongaro has signed an agreement with BIPM to mark the international recognition of the ESA timescale and the addition of ESA’s atomic clock data to the UTC calculations. “This is an independent timing capability that ESA’s Navigation Laboratory — based in ESTEC in the Netherlands — built up to support validation of Galileo timing performances, and before it the experimental Galileo GIOVE satellites,” explained Pierre Waller of ESA’s RF Payload Systems division.

This enhanced version of the SSU 2000 will be the first in a series of forthcoming Symmetricom products that include GLONASS capabilities.

Available as an integrated card for the Symmetricom SSU 2000, the GLONASS referencing feature will allow customers to support both GPS and GLONASS simultaneously, providing added protection should signals from one navigation system become unavailable. GPS has long served as the primary reference signal for timing and synchronization in telecommunications and other networks. Operators in some regions prefer to use the GLONASS system, either as the primary time reference or in conjunction with GPS signals. Symmetricom has enhanced the SSU 2000 satellite receiver functionality to meet this demand.

“GLONASS signals have become an important primary reference for timing and synchronization systems,” said Laura Finkelstein, vice president of product management for Symmetricom. “The SSU 2000 is well-established as the synchronization platform for communication service providers globally. The integrated capability to simultaneously support both GPS and GLONASS provides our customers another way to improve the reliability of their network.”

Timing and synchronization are a focal point technology in Ethernet and mobile carrier networks today. Synchronous Ethernet allows frequency signals to transfer at the physical layer over Ethernet, helping improve network reliability by offering synchronization services to Carrier Ethernet networks. Using SyncE to complement IEEE 1588 Precision Time Protocol (PTP) can enhance PTP services being delivered to mobile base stations deployed in radio access networks. The new SSU 2000 capability puts SyncE and PTP on the same output port, thus providing an ideal synchronization solution for the evolution of mobile networks as they extend coverage and increase capacity.

Designed in a NEBS-compliant package, the SSU 2000 integrates intelligent functional modules into a flexible, fully redundant system. This enables telecom network operators to seamlessly satisfy current and future requirements for generating and distributing superior synchronization signals for advanced network services.

The SSU 2000 has been deployed in more than 125 countries as a timing and synchronization distribution system for communications service providers.

The Smart Grid has brought about power technology advancements that fundamentally change substation operations. Power equipment and their data networks are shifting from simple, reactive control and reporting to proactive, real-time management and operations control, making advanced synchronization and timing more critical than ever, according to Symmetricom. The SGC-1500 Smart Grid Clock is designed to address this need, enabling power equipment to operate more efficiently and closer to its operational limits. For example, one microsecond accuracy is required by the phasor measurement unit (PMU) for real-time network situational awareness and overall operational efficiency. Without accurate time stamps, PMU data has limited value. For power utility companies, that translates into enhanced network utilization rates as well as smarter management and mixing of renewable and traditional power sources.

“Power and utility companies are increasingly looking to source the latest technology innovations in order to modernize their infrastructure,” said Greg Neichin, executive vice president, Cleantech Group. “Over the past three years, we have tracked more than $700 million in venture investment committed to companies developing smart grid products. These are all data-intensive applications that will rely heavily on precise timing and synchronization, as well as more advanced analytics to process these vast streams of new information.”

“The Smart Grid architecture and related standards require a new approach to timing distribution across the overall network,” said Manish Gupta, vice president of marketing and business development for Symmetricom. “Symmetricom brings extensive experience in delivering precise time to the communications, government, and enterprise markets. Serving the power utility telecom network over the past 10 years, Symmetricom is ideally positioned to meet the emerging timing requirements of the Smart Grid.”

The SyncServer SGC-1500 meets key requirements of Smart Grid substations, including:

• Microsecond accuracy and resiliency — referencing GPS satellite signals, the Symmetricom Smart Grid Clock distributes timing with microsecond accuracy over the local area network (LAN) using the IEEE 1588 v2 Precision Time Protocol (PTP) Power Profile or IRIG-B time code.
• IEC 61850 — the International Electrotechnical Commission’s (IEC) standards for the design of electrical substation automation, which requires microsecond timing to identify and mitigate a potential fault condition in real time. This standard also identifies important electrical hardening requirements for substation environments.
• NERC CIP ― the North American Electric Reliability Corporation (NERC) reliability and security standards for Critical Infrastructure Protection (CIP), which calls for high strength security protocols.

The SyncServer SGC-1500 comes with additional industry leading capabilities such as a built-in IEEE 1588 v2 Telecom Profile input option. This enables the Smart Grid Clock to derive time from the communications wide area network (WAN), thus eliminating the need to have GPS at every substation and PMU. The Rubidium atomic clock option offers holdover capability in the event of GPS disruption. These options result in a highly cost effective and resilient solution for power utilities.

Editor’s Note: This article reproduces the acceptance speeches given by the winners of GPS World’s 2012 Leadership Awards, at the Leadership Dinner in Nashville in September. The Leadership Dinner was sponsored by Lockheed Martin and Deimos Space.

Remarks by Robert Lutwak, Symmetricom; Chief Scientist, winner in the Products category. His expertise is practical advances to overcome the intrinsic physical barriers to affordable chip-scale atomic clocks, enabling precision time and time transfer in mobile GNSS and communications systems.

Thank you to the awards committee and especially to the individual who nominated me.

I would be remiss if anyone left here with the impression that the development of the chip-scale atomic clock was in any way a solo effort. On the contrary, while I have had the privilege of being the front man, the success of this program can be attributed entirely to the fantastic collaboration between three highly disparate groups, from very different industries and cultures: our Research Group at Symmetricom’s Technology Realization Center, in Beverly, Massachusetts; the MEMS group at the Charles Stark Draper Laboratory, led by Mark Mescher and Matt Varghese; and the optoelectronics group at Sandia National Laboratories, led by Darwin Serkland.  If any of these groups and people had been anything less than extraordinary, both technically and personally,I would not be standing here this evening.

With this introduction I can say, with little loss of humility, that the chip-scale atomic clock (CSAC) is a really cool device. Depending on where you’re coming from, it’s either 100 times lower size, weight, and power (SWAP)  than traditional atomic clocks or it’s 100 times more accurate than quartz oscillators with comparable SWAP. Regardless of your perspective, it clearly represents a disruptive technology and a paradigm shift for portable battery-powered navigation, communication, and timing applications. For comparison, the CSAC can run for a day on a full cellphone battery charge, whereas the next lowest power clock of comparable performance will run down a car battery in an hour. The CSAC is not an evolutionary improvement in SWAP, it is revolutionary in that it enables previously untenable system architectures, mission scenarios, and network topologies.

Since Symmetricom introduced the first commercial CSAC, roughly two years ago, the market response has been overwhelming. Despite having done our due diligence to predict the market demand and despite having nearly doubled our manufacturing output every quarter, our shipment backlog remains strong, and I am frequently surprised by innovative customer applications that we had not envisioned at the product launch. We have to date shipped many thousands of CSACs to more than a hundred different customers, representing vastly different markets and applications. While many of the novel applications are still in the early stages of prototype development and evaluation, it is clear that CSACs will be ubiquitous across diverse applications within the decade.

I am fortunate, in my position, to interact directly with the technical integrators of the CSAC and learn the details of many of the applications. My general impression is that the timing and frequency stability performance of the CSAC is adequate for most of the emerging applications. The most common requests that I hear from customers are for reduced cost, power consumption, and size, in that order. It is not surprising that size is at the bottom of the list. In most applications, the batteries are still larger and heavier than the CSAC, so small improvements in power consumption are generally more valuable to reducing system SWAP than size reduction of the CSAC itself.

As in any new technology, the cost will come down naturally with increased volume and improved manufacturing efficiencies, both at Symmetricom and at our vendors. While it is unlikely that you will get a CSAC in your next free cellphone, I do expect that the cost will progressively decrease over the next several years, and the technology will become cost-viable to an exponentially increasing spectrum of applications. Similarly, we continue to evolve our electronics and algorithms for improved power consumption, aided by external advancements in microwave and microprocessor electronics driven by the smart-phone industry. It is my expectation that a factor of 2X improvement in power consumption is likely within the next three to five years.

To date, most of the commercial products that have emerged, based on CSAC technology, have been in the timing and frequency calibration space. It is not surprising to me that the time and frequency community was the first to adopt and exploit the technology, as many of them have been closely monitoring the development program and had the internal expertise and experience to rapidly exploit it.

I admit, though, that I am a bit disappointed to see that there are no papers with “CSAC” in their titles at the 2012 ION-GNSS, but I am confident that this will change in the years to come. Adoption of CSAC by the navigation community has lagged behind the timing community in large part, I believe, because the technology has caught the community somewhat off-guard, and the benefits of the CSAC to INS and GNSS are just now beginning to be realized.

The most obvious and straight-forward application of CSAC to GNSS is rapid P(Y) acquisition; we have demonstrated 15-second time-to-subsequent-fix (TTSF) after two hours of GPS denial. This was a fairly simple demonstration that consisted of jamming time into an unmodified GPS receiver, but I believe that this is just the tip of the iceberg. With access to the core navigation algorithms within the receiver, precise knowledge of time could improve the receiver performance and reliability on other levels, including (at least):
◾    Improved uncertainty of the navigation solution
◾    Navigation with less than four (or less than three) satellites
◾    Anti-spoof and anti-jam detection
◾    Seamless co-integration of GNSS and INS systems

Another navigation area that I believe is ripe to benefit from CSAC technology is in self-assembling navigation systems, such as a local ad hoc GNSS-like network which self-assembles from handheld timing beacons/receivers. Such a system would have value for safety-of-life applications in GPS-denied environments, such as indoor firefighting and mine safety.

Thank you again for the recognition and opportunity of this award.