Locata VRay antenna

It’s About Time

This entry is part 8 of 8 in the series xyHt in print September 2014
Australia tech-rebel company Locata is poised to profoundly change the world of positioning, navigation, and timing.

In 1994 in Canberra, Australia, accomplished musician and entrepreneur Nunzio Gambale was introduced to a fellow musician, David Small, by Gambale’s cousin who had been giv­ing Small a hand with an interesting experi­ment. This chance meeting began an amazing partnership in technological development.

The scenic capital territory of Austral­ia has its fair share of domestic and interna­tional tourists; Dave Small’s experiment was testing the use of GPS to help trigger com­mentary and information on devices tour­ists could carry to help guide them around the stately parkways and museums. This was long before smartphone navigation—it was a novel idea at the time. As is the habit of this particular duo, they quickly identified a prob­lem they knew just had to be “fixed”: tour­ists would definitely want to go inside where GPS did not work.

This realization was the first of the many holes in the Swiss cheese of GPS that Gam­bale likes to point out. It is not so much that Locata paints GPS/GNSS as “bad” or ob­solete for what it was originally designed to do. The more the duo used and understood GPS the more they understood that satel­lite-based systems alone could never deliver on all future expectations. There were more than enough holes to warrant augmentation, supplementation, and development of com­pletely new alternatives.

“Dave is one of the most fearless people in the world,” says Gambale. “There is not a single technical challenge he will not take on.” Imagine someone asking you to local­ly replicate GPS, without atomic clocks, sat­ellites, or the mega-budget of a superpower nation. And it has to be affordable enough for any size company to deploy.

Small, the chief inventor at Locata, with his background in ham radio, music, broad­cast television, and recording, has an innate sense of the nature of waveforms and sig­nals. Plus being an insatiable tinkerer with various radios, electronics, instruments, and sound systems, Small was up for any chal­lenge. While talking to Small and Gam­bale I got the sense that they would go as far as splitting atoms to solve engineering conundrums.

History is full of inventors and non-tra­ditional scientists who tinkered their way to success. Arguably, the most profound inno­vation in navigation was the solving of lon­gitude and the work of the 18th century clockmaker John Harrison. Gregor Men­del, DaVinci, Franklin, Bell, Edison, Niko­la Tesla, and many more were consummate tinkerers. Then there was the bicycle-me­chanic siblings who stood on the sand dune in North Carolina a century ago launching humankind into the heavens.

The way GPS/GNSS works, Small and Gambale determined, would be perfectly sound for original goals, but for future mo­bile applications they had to improve what it could do. Indoor location is one thing; there are a many indoor navigation approaches: emitted RF ranging, pulsed signals from lights, photogrammetry, sonic imaging, WiFi ranging, and more. These “alternate technol­ogies” were never designed for high-preci­sion positioning.

What Small and Gambale had in mind was much more reliable, higher-precision in­door positioning: elegantly extending GPS, relaying, repeating, emulating, or imitating what GPS can do—but indoors and any­where else needed. There was period of re-examining the fundamentals of how GPS works, and they soon understood that the key to everything was in time and time synchronization.

 

Timing Really Is Everything

NEARLY EVERY PROFOUND innovation in po­sitioning and navigation since the days of Harri­son’s nautical clock (his H5 Chronometer is shown below) has relied on some element of time: sonar, radar, laser-ranging and RF-based EDMs, LORAN, ADSB, et al., and GPS/GNSS. Many solutions are variations on the same themes of ranging, rays, or beams where required synchronization levels are extremely tight. Radio signals travel at the speed of light; there is little margin for error.

It was the Doppler effect of the very first Sputnik, tracked by Johns Hopkins University, that confirmed the global navigation system’s theories of scientists and visionaries like Arthur C. Clarke. The first global navigation test system by the U.S. was aptly dubbed the “Timation” system, with the Doppler-based Tran­sit system following in the early 1970s. GPS would put all of these elements together: atomic clocks, syn­chronized time (within 20-30 nanoseconds), tracked orbits—enabling code and carrier ranging.

Speed-of-light signals are perfect in a vacuum, but on the ground one has to consider delays in sig­nals from the ionosphere and troposphere. And then there is the warping of space-time itself. That fellow Einstein was right: time will vary be­tween two observers in locations of varied grav­ity and orbit. GPS satellites are around 20,000km out; at that reduced gravity their atomic clocks run about 38 nanoseconds apparently faster than an identical clock on the ground. Without the time dilation being taken into account and without satellite clock offsets being constantly tracked and updated, GPS positions would go out of useable range in a short span of time.

Globally we rely heavily on satellite and atomic clock-based global timing. The global timing capa­bilities delivered by GPS/GNSS are used by far more people and applications than for positioning and navigation, by orders of magnitude. Network com­puting and telecommunications have evolved into the magic we take for granted only by leveraging this time element. Achieving extraordinary levels of time synchronization without atomic clocks—that is the revolution in timing that Locata has ignited.

 Bringing Time Synchronization Down to Earth

The Locata founders decided to take a look at just how far they could advance the timing aspect of positioning. It was not en­tirely a new undertaking; nearly half a century earlier at the Na­val Research Laboratory near Washington, D.C., scientists set up a network of atomic clocks, ground transmitters, and receiv­ers to test what would become of the Timation satellite navi­gation experiment. Locata’s ap­proach was to have components synchronize like instruments in a band. Results were unprecedented.

On the surface, a LocataLite transmitter works just like a GPS satellite, sending code and carrier, and the LocataLite “slaves” do the very same thing, creating a net­work of positioning signals. The key to the system and its incred­ibly precise relative positions (and time) is the local synchroniza­tion of time. Locata calls this their “TimeLoc” technology, enabled by a heavily patented synchronization methodology called Time Lock Loop (TLL).

Whereas GPS/GNSS relies on global time synchronization via many atomic clocks, tracking networks, updates, offsets, con­tinual monitoring, and adjust­ment, a network of any number of LocataLites can, within mo­ments of being turned on, achieve local, synchronized time in the range of a few nanosec­onds and picoseconds (see “Pi­coseconds,” below).

Small’s initial spark of inven­tion was sound; Locata could be developed to work indoors, out­doors, in sky-view-challenged areas, and even potentially in GPS-compromised battlefield scenari­os. Now it was time to productize. Small and Gambale understood that their solution was not only re­al-time-survey-grade for positioning where GPS did not work, but also a scientific-grade timing solution.

Gambale was already a pioneer­ing businessman. In the early 1980s when others in the music indus­try brushed off his idea of sending mail-order catalogs for musical in­struments to the farthest reaches of Australia, every “you’re crazy, mate!” steeled his resolve, and he grew his startup, Pro Audio Supplies, into a multimillion dollar enterprise— which he could now sell to help fund development of Locata solutions. The pair started to challenge tradi­tional precision positioning and tim­ing markets, and those markets have taken notice.

Real-time centimeter positioning in places where GPS/GNSS can’t reach represents substantial market potential. Think of precision guid­ance for machine automation and large-scale metrology for manufac­turing on huge indoor factory floors or for construction of buildings and major struc­tures, shipyards, warehouses, and port facilities. The Locata solution has certain advantages be­yond just working in places where the satellites are not in view; it works at much higher power ranges and can be deployed to work at complete­ly different frequencies making it more immune to jamming and interference.

GPS/GNSS downtime can be critically im­portant for safety-of-life uses and quite cost­ly for commercial activities. In a huge mining operation, for instance, a loss of high-accura­cy machine control can cost the miner tens of thousands of dollars per hour. Leica Geosys­tems recognized this and sought Locata as a de­velopment partner for a hybrid solution their customers urgently desired (see “Eliminating Downtime,” page 17).

 

Picoseconds

Locata has developed a close relationship with the University of New South Wales (UNSW), that’s independently examined many aspects of Loca­ta technology, including real-world use-case tests. One test involved setting up a LocataNet around central Sydney Harbor, with UNSW students testing Locata’s positioning capabilities, both indoors and outdoors.

However, it was a 2013 synchronization project and academic paper that caught the attention of the international scientific timing community. An ar­ray of LocataLites was installed on towers in the Snowy Mountains of New South Wales at distances of 45km and 28km respectively, a total range of 73km specifically for time transfer tests. This closed system repeatedly yield­ed differences between the pulse-per-second signals of co-located GPS in the order of mean deviations of a few nanoseconds and a few hundred picosec­onds standard deviation.

The only other way to achieve such precise time transfer would be lasers and fiber optics, not always practical or affordable. A truly broad­cast-signal-based system of this accuracy would have far-reaching utility, opening whole new fields of innovation in telecommunications, distributed computing, navigation, guidance—and a much-needed backup and alterna­tive to GPS/GNSS for timing of critical systems.

The conference paper on the tests, by UNSW’s Rizzos, Glennon, and Dempster, was presented by co-author Joseph Gauthier at the U.S. Institute of Navigation’s Precise Time and Time Interval Conference held in Seattle in December 2013. Gauthier noted that Locata allowed tropospheric condi­tions to be taken into account. The researchers could observe miniscule vari­ations of the speed-of-light signals. “It was great that any biases we saw could be completely accounted for,” said Gauthier. Results have inspired the planning of synchronization trials in several major cities.

 

What Clock Tests the Test Clocks?

THE U.S. GPS NAVSTAR constellation of satellites was funded and de­veloped by a military program but has ironically provided tangible

LocataLite deployed at the site of initial tests for the USAF at the White Sands missile range in New Mexico.

LocataLite deployed at the site of initial tests for the USAF at the White Sands missile range in New Mexico.

commer­cial, scientific, and even consumer benefits hundreds if not thousands of times greater than the original investment. Defense also considers non- GPS systems to mitigate battle space GPS-compromised environments (considerations rightly for safety-of-life and critical functions in the civilian sector as well … but more about that later).

The USAF developed the Ultra High Accuracy Reference System (UHARS). This system is, by design, the world’s best non-GPS benchmark for testing navigation. The USAF’s Central Inertial and GPS Test Facility at Holloman Air Force Base in New Mexico played a key role in the initial de­velopment of GPS and is now charged with getting the UHARS up, tested, and deployed. They contracted with Locata to use its LocataNet and Time­Loc solutions as core-enabling technology, allowing the UHARS to serve as the time and ranging “truth” for future GPS testing.

A LocataNet (or array of synchronized LocataLites) was first trialed by the USAF at the White Sands Missile Range. The USAF reported exception­al results for terrestrial and airborne tests over thousands of square kilom­eters—beyond expectations. Over many days of testing, Locata’s non-GPS solution could position an aircraft traveling at ~400 mph, at a range of over 35 miles, to a few inches’ precision in real-time. Locata is the key compo­nent for the new “truth system” for the testing of future navigation systems for the U.S. Department of Defense.

GPS 2.0

Locata components are small, easy to deploy, and quick to get synchronized. Gambale likes to characterize a LocataNet as “your own GPS” or “your personal constellation”; he has even trade­marked “GPS 2.0” to emphasize the potential future impact of such technologies on the evolu­tion of radio-based position­ing solutions.

The original motivation for development was lack of outdoor/indoor transition options at the time. Fast for­ward to the present day when Locata systems are hitting multiple early-stage mar­kets, and Locata can rightly tout one of the most pre­cise, if not the most precise, non-laser indoor positioning solutions.

Other indoor navigation and location-based services are happy with low precision, but there are very real needs for centimeter-ac­curate indoor positioning services, especially on moving objects. One such implementation is at a world-renowned vehicle crash test facility (see “Flat Robot” at the right).

Note that Locata is not being touted as a solve-everything alternative to GPS/GNSS or that it in any way could completely replace GPS/ GNSS, the nickname of “GPS 2.0” notwith­standing. There are so many significant merits to and proven applications for Locata solutions as to warrant very little spin. If I might take ex­ception to some of what supporters of GPS/ GNSS alternate solutions like Locata have, in some cases, promoted as an unfortunate “us-vs.- them” stance: pointing out where other systems cannot work is secondary to showcasing how Locata’s solution can fill in, sup­plement, and even improve what GPS/GNSS and other naviga­tion, timing, and positioning sys­tems do.

There are certain situations where Locata could not com­pletely replace current global systems but could end up im­proving them. Locata could not (at present) work across oceans or even country-sized terrestri­al regions (not without massive infrastructure investments). A lot of multi-use combined im­plementations have been envi­sioned because Locata networks can be scaled from the size of a room to thousands of square miles. For example, a highway corridor could be lined with a LocataNet and serve not only positioning and navigation but also as a time-transfer back­bone. Entire cities could have dense networks by installing Lo­cataLites on cell towers, provid­ing resilient seamless indoor and outdoor positioning.

Nevertheless, Locata signals are still susceptible to the very same physics that degrade GPS/ GNSS and other legacy systems, like multipath. Radio signals bounce off obstacles and ob­jects in cluttered environments like cityscapes, and the resultant multipath creates havoc for ac­curate radio positioning. Small and Gambale knew they would have to eventually have to face the multipath devil (see “VRay,” below).

Eliminating Downtime

“This was the first [system] we have ever deployed which completely exceeded our expectations,” said John Carr, fleet man­agement

A Jigsaw system (hybrid Locata & GNSS solution by Leica Geosystems) was set up on the rim of the Boddington Mine in Western Australia, providing precise real-time positioning for drilling rigs on the mine floor.

A Jigsaw system (hybrid Locata & GNSS solution by Leica Geosystems) was set up on the rim of the Boddington Mine in Western Australia, providing precise real-time positioning for drilling rigs on the mine floor.

specialist at the Boddington Gold Mine in Western Australia. The system Carr is referring to is a mix of positioning tech­nologies that is sold by Leica Geosystems as the Jigsaw Positioning System (JPS). Initial­ly developed for the mining market, the full system consists of a network of LocataLite “beacons” on the rim of the open pits. Leica Geosystems’ JPS receivers are a combined GNSS receiver board and a Locata receiver board using LocataLite signals interchange­ably with satellite signals.

Carr first installed the Jigsaw receiv­ers and antennas on the drilling rigs that constantly crisscross the open mine, drill­ing precise holes (within an inch) for blast­ing as the floor of the mine drops from the current depth of 300 meters to a planned fu­ture depth of over 900 meters. The problem, of course, is that as the mine gets deeper, fewer and fewer satellites are in view. GPS/ GNSS solutions deteriorate further as the depth increases.

“The JPS,” explains Frank Takac, chief engineer and head of R&D GNSS Position Engineering with Leica Geosystems, “in­corporates the available GNSS signals into the solution, thus adding some high eleva­tion signals to improve the overall geometry of the ground network. To achieve this in­tegration, we estimate all of the unknowns between GNSS and the Locata system in a tightly coupled solution.”

Carr has been thrilled with the results and how easy it was to deploy. “We set up the LocataLites on the rim, using solar panels for power,” he said. “Once we turned it on the whole network synchronized right away, and we could simply start using it. Downtime in the mine can be quite costly, and as for the drilling rigs with Jigsaw deployed, any downtime since then has not been due to the navigation system.”

Flat Robot

One recent clear morning in ru­ral Virginia I witnessed a car applying the brakes to avoid hitting a slower-moving car ahead: a commonplace event except that car had no driver, nor did the “target” car. These were test vehicles at the famed In­surance Institute for Highway Safety (IIHS) research facility in Ruckersville, Virginia, and they were solely guided by Locata.

Historically, controlled crash tests in­volved vehicles guided along tracks for head-on, side, or rear collision tests, re­vealing how safety features like airbags and seatbelts performed. Now the empha­sis is crash avoidance systems, automat­ed hazard detection, and braking: options available on many new vehicles like the camera-based system tested on a new Subaru that day. The only truly meaningful tests have to be done on freely travelling vehicles in real-world conditions. Robotics provides the answer.

Dr. Paul Perrone and his team from Per­rone Robotics, leaders in providing guid­ance, automation, and systems for testing laser measurement, took up the challenge to provide robotics guidance for the IIHS. Vehicles would need to be guided at very precisely measured and repeatable high­way speeds and trajectories—and would need to experience actual “collisions.”

Safety of test drivers and cost of ve­hicles spurred Perrone to develop a “flat robot”: a flat four-inch-high steel “skate” with beveled edges, about the footprint of a car. It is driven by electric motors capa­ble of highway speeds, acceleration, and response. This “target car” has a full-sized modular-foam-block facsimile built on top of the skate before each test. The auton­omous, robotically driven test car can hit the target car and harmlessly run right over the skate, but with a kind of comical explo­sion of foam blocks. Watching this is a lot of fun.

The key to guidance is the array of Lo­cataLites set up around the test site. The robots have Locata “receivers” on board, with the antennas on the foam target car protected by what the team has nicknamed antenna condom covers that harmlessly bounce aside during a crash.

IIHS is completing construction of its huge indoor track sometime this year; GNSS would then no longer fit the bill, whereas Locata will. But also, notes Per­rone Robotics Geoff Hoekstra, with Locata, “we have a much more controlled environ­ment where we can control any number of vehicles at any number of speeds and test scenarios, indoor and out.”

VRay: The “TimeTenna”

A hazard befalling GPS/GNSS and any other radio-based ranging sys­tem is multipath; signals bounce off things, take longer to get to a receiver than a direct signal, and seriously af­fect time-of-flight computations. GNSS antennas and receivers use many physi­cal and algorithmic features to mitigate this: choke rings, ground planes, etc. Unfortunately, any system designed to work indoors or in urban canyons or other places where GPS/GNSS does not work well is going to be subject to even more multipath hazards than any clear-sky GPS/GNSS uses. This only in­spired Small and Gambale to take an even bigger leap into inventive scien­tific research.

The “standard” Locata antennas may look quite simple, and most mul­tipath mitigation takes place in the positioning solution. But for high mul­tipath environments Small has invent­ed a whole new class of antenna. It is designed to leverage the well-known benefits of beam-forming provided by phased array antenna techniques. Phased arrays and beam forming (Goog­le it!) are the magic behind sonar and radar. The Vray samples signals arriving at multiple antenna elements and then process the “data packets” to gener­ate vast numbers of virtual beams. The VRay trademark is a nod to these “virtu­alized rays.” Read more at locata.com/ article/vray-antenna/.

Some traditional phased arrays can have up to thousands of antenna ele­ments, and every element is serviced by an individual “radio front end.” The massive amount of data generated by this multitude of signals on, say, a war­ship requires refrigerator-sized racks of computers. In contrast, any number of antenna elements can be used for a VRay and serviced by a single stock-standard Locata receiver—very inex­pensive to produce. They are already available for early- stage commercial markets like indus­trial warehousing and port machinery automation.

Though designed for different ap­plications than many traditional phased arrays, the VRay produces a stagger­ing 2+ million virtual steered beams per second at a fraction of the cost. Vray antennas have yielded cm-level posi­tioning in steel warehouse-style build­ings where any standard positioning antenna fails almost immediately. It should also be noted that this precise 3D orientation of mobile platforms is achieved without using a gyroscope or inertial unit. Locata has signed a coop­erative R&D agreement with the USAF to show the military researchers how VRay techniques can be applied to GPS receivers. Keep your eyes open for news of further development in this area.

When Small and team invented and then developed this new platform of phased array technology, it was nick­named the “TimeTenna.” The current VRay is about 12” in diameter and clear­ly a huge leap from initial prototypes. It is, and always has been, a commercial-off-the-shelf development. The VRay is a far cry from its military-use ancestors; it is designed solely with commercial positioning and navigation in mind. It’s already an astounding piece of engi­neering, and the next step logical­ly is making smaller versions without compromising its core capabilities.

Wider Markets

Locata has won the attention of science and academia, precision guidance, indoor navigation, and other related industry segments. The next phase well under way is productization for wider markets. Locata has recently revealed a multi-year “skunkworks” project, a version of VRay miniaturized to smartphone-deployable size.

The patents are all in place, the initial systems are working in their labs, and they intend to demonstrate it to relevant play­ers in the coming year.

Attention as an alternative to GPS/GNSS for safety-of-life, timing, and critical infrastruc­ture continues to grow. Earli­er this year Gambale was asked to present before the U.S. Fed­eral Positioning, Navigation, and Timing (PNT) Advisory Board in Washington, D.C. on those very subjects. It is also clear to the Locata team that many of its new techniques can be im­plemented on the GPS/GNSS receiver end. This has led the United States Air Force Insti­tute of Technology to sign up for access to VRay technology to study feasibility in GPS anten­na design. It appears the student may soon be teaching something to the master.

Locata has already been im­plemented in many early-stage markets, as our examples have shown. How long will it be be­fore you see Locata technolo­gy commonly implemented at construction sites, in the central districts of cities, along highway corridors, inside manufacturing facilities, at critical facilities for timing? That’s always the tough­est question for any new and dis­ruptive technology. With new large contracts for more mines and port facilities in hand it seems the mainstream has found Locata. The team continues to relentlessly pursue productiza­tion of their latest inventions while keeping an eye on the next wave. We should not be sur­prised if elements of their an­tenna technology now begin to find their way onto your stand­ard GPS/GNSS units.

This team has already pulled off astounding upset wins against all odds, and in many ways the season has only just begun.

Flat Robot skate

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