Something struck me as I scanned the 280-odd presentations listed under 36 session tracks: the frequency with which the word BeiDou appeared. To determine if there were any substance to this fleeting impression, I essayed a quantitative analysis. Naturally, GPS and the generic GNSS occurred times beyond measure, but this is how the others fared.

IRNSS: 1
QZSS: 3
GLONASS: 10
Galileo: 13
BeiDou: 19.

What does this signify? Little enough, possibly. Still, something. A satellite navigation system bursts seemingly out of nowhere and within a few short years virtually laps the field, putting 20 (14 usable) transmitters into space and establishing a regional operating capability, soon to be global. That sort of thing tends to get noticed.

The titles of BeiDou-focused papers on tap this fall in Nashville — not all of them springing from the laptops of Chinese engineers, not by a long shot — add substance to this passing fancy.
◾    BeiDou Consumer Receiver Chips at Last.
◾    A Combined GPS/BeiDou Vector Tracking Algorithm for Ultra-tightly Coupled Navigation Systems.
◾    Towards the Inclusion of Galileo and BeiDou/Compass Satellites in Trimble CenterPoint RTX.
◾    New Assisted BeiDou Products from JPL’s Global Differential GPS System.
◾    BeiDou Integration in Cell Phones and Tablets.
◾    BeiDou — A System That is Now Ready for Applications.
◾    Augmenting GPS RTK with Regional BeiDou in North America.
◾    New Systems, New Signals, New Positions — Providing BeiDou Integration.

The affiliations of some of the authors of the above read like a top-level directory of North American and European GNSS manufacturers. Clearly, the ground has been plowed and the fields lie ready — if they are not already planted. Unless that’s too mixed a metaphor for satellite radionavigation signals.

The recent acquisition of one Western GNSS manufacturer by a major Chinese business concern has not gone unnoticed, either.
For more intelligence, I consulted the newest member of this magazine’s Editorial Advisory Board. He replied to my emailed penny for his thoughts.

“I would be happy to contribute a column for the July issue based on my observations here at the China Satellite Navigation Conference in Wuhan. The article would be titled: Little Tigers versus Wolves.”

Wow. Now I wonder, who’s who?

This first FOC satellite is functionally identical to the first four in-orbit validation (IOV) satellites already in orbit, but has been built by a separate industrial team. Like the other 21 FOC satellites so far procured by ESA, the satellite’s prime contractor is OHB System AG, and the navigation payload was produced by Surrey Satellite Technology Ltd. in Guildford, UK.

Thermal vacuum testing at the European Space Research and Technology Centre (ESTEC) will simulate temperature extremes the satellites must endure in the airlessness of space throughout their 12-year working lifetimes. Without any moderating atmosphere, temperatures can shift hundreds of degrees from sunlight to shadow.

Other activities on the schedule include shaker and acoustic noise testing — simulating the vibration and noise of launch — as well as electromagnetic compatibility and antenna testing, placing the satellite in chambers shielded from all external radio signals to reproduce infinite space and check that its various antennas and electrical systems are interoperable without harmful interference.

“The Galileo FOC satellites provide the same capabilities as the previous IOV satellites, but with improved performance, such as higher transmit power,” explained Giuliano Gatti, the head of the Galileo Space Segment Procurement Office. “They are to all intents a new design that requires a full checkout before getting the green light for launch.”

The second FOC flight model is due to arrive at ESTEC in early June, and the third in the middle of July. The first two satellites are to be placed in orbit on board a Soyuz launcher, with a scheduled lift-off from Kourou in French Guyana this fall, with two more due to follow by the end of the year.

The first four Galileo IOV satellites, launched in 2011 and 2012, were provided by EADS Astrium with Thales Alenia Space Italy responsible for integrating the satellites and Astrium in Portsmouth, UK, providing the navigation payloads. They provided their first navigation fix in March 2013.

The definition, development and in-orbit validation phases of the Galileo programme are being carried out by ESA and co-funded with the European Commission (EC).

The subsequent FOC phase is managed and funded by the EC. The commission has delegated the role of design and procurement agent to ESA for the FOC phase. At the same time as the satellites are being assembled on a production-line basis, ground stations are also being established on European territories around the globe.

Photo credit: Pat Corkery, United Launch Alliance.

GPS Leaves This Earth

A t 5:38 p.m. Eastern Daylight Time (21:38 UTC) on May 15,  the fourth GPS IIF satellite, Space Vehicle Number (SVN) 66 built by Boeing, ascended towards orbit aboard a United Launch Alliance Atlas V rocket at from Cape Canaveral Air Force Station, Florida.

“The GPS constellation remains healthy and continues to meet and exceed the performance standards to which the satellites were built. Our goal is to deliver sustained, reliable GPS capabilities to America’s warfighters, our allies, and civil users around the world, and this is done by maintaining GPS performance, fielding new capabilities and developing more robust modernized capabilities for the future,” said Colonel Bernie Gruber, director of the U.S. Air Force Space and Missile Systems Center’s GPS Directorate.

The new capabilities of the IIF satellites will provide greater navigational accuracy through improvements in atomic clock technology; a more robust signal for commercial aviation and safety-of-life applications, known as the new third civil signal (L5); and a 12-year design life providing long-term service. These upgrades deliver improved anti-jam capabilities for warfighters and improved security for military and civil users around the world, the Air Force said in a statement.

The IIF-4 satellite is expected to complete testing in August, after which it will be utilized as a reserve or backup satellite. It becomes the fourth satellite in a 12-strong network of GPS IIF spacecraft manufactured by Boeing as lead contractor, the first of which was boosted into orbit in May 2010. The Air Force expects the first of the next-generation GPS IIIA satellites to enter service sometime in 2014.

System Briefs

GLONASS. The GLONASS 747 M-series satellite launched on April 26 has maneuvered into an orbital slot near GLONASS 728, the operational satellite in Plane 1, slot 2. 747 will presumably serve as a reserve until it replaces 728, unless another Plane 1 satellite expires first. The next Russian launch, a GLONASS-M trio, is scheduled for July 1. There are currently 24 operational GLONASS satellites.

IRNSS. The first Indian Regional Navigation Satellite System satellite is expected to rise at the end of June. The IRNSS plans to orbit of seven: three geostationary and four geosynchronous, providing regional coverage via navigation signals in the L5 and S bands.

Commented one knowledgeable source, “This is a very disturbing report and could spell the end for OCX. Although the GAO has some facts wrong, the basics are correct. Many of us have been pushing for an alternative, more capable, and much less costly system for years.”

Raytheon Intelligence and Information Systems won a $886.4 million prime contract to develop the OCX in February 2010, with an initial delivery date of 2016.

In December 2012, Col. Bernie Gruber of the U.S. Air Force GPS Directorate wrote in the pages of GPS World what was the commonly accepted perception of and public government position on OCX:

“Along with a host of additional satellite capabilities and signals, we will correspondingly modernize our ground segment. Our Next-Generation Operational Control System (OCX) is designed to command and control our modernized secondary civil signal L2C, safety-of-life signal L5, and the internationally compatible signal L1C.  . . . . . As the modernized signals become operational, users will see faster signal acquisition, enhanced reliability, and a greater operating range. The information assurance, expandability, and service-oriented architecture will afford users and operators with security and information they simply don’t have today.”

The View from 2013. The 190-page GAO report, “Defense Acquisitions: Assessments of Selected Weapon Programs,” states that the scope and complexity of key OCX program elements was underestimated, and characterized the situation as typical of overruns that have historically beset Pentagon space programs.

Although the report (click here for highlights and to download the full PDF) found that “The Department of Defense (DOD) 2012 portfolio of 86 major defense acquisition programs is estimated to cost a total of $1.6 trillion, reflecting decreases in both size and cost from the 2011 portfolio,” and that “Continuing a positive trend over the past four years, newer acquisition programs are demonstrating higher levels of knowledge at key decision points,” .

The next-generation GPS ground-control system, known as OCX.

Two of the 190 pages in the document specifically address OCX, which is identified as one of 19 weapons “Programs That Entered Development with Technologies Fully Mature or Nearing Maturity” and one of 14 “Programs with technologies nearing maturity at knowledge point 1 date.” OCX is given a knowledge point 1 date of November 2012.

According to the Report, “Air Force officials recently stated that, although GPS III is still maintaining an April 2014 “available for launch” date for the first satellite, the planned launch date is being moved to May 2015 in order to synchronize it with the availability of the GPS Operational Control Segment (OCX) Block 0, without which the satellites cannot be launched and checked out.”

“The program has experienced significant requirements instability and schedule delays while in technology development,” the report reads. “The contractor initially underestimated the scope and complexity of the necessary information assurance requirements which required additional personnel with the necessary expertise and increased government management.”

Changes in Specifications. In June 2012, a Raytheon executive stated that the OCX contract had been significantly modified, with the addition of a launch and checkout capability that had previously been the responsibility of Boeing, prime contractor on the GPS IIF satellites.

He also identified information assurance, a primary OCX requirement, as “a big challenge. It is very important that we protect this system against the current and evolving cyber threats because they are real and the nation can’t afford to have this system compromised.”

An Update Last Autumn. In a November 2012 conversation with GPS World defense editor Don Jewell, Raytheon VP and Program Manager for OCX Ray Kolibaba made the following remarks:

“We currently have 450 people at Raytheon working OCX, and with our subs, an additional 300 personnel. Altogether we have 750 personnel working GPS and OCX issues. This does not include the military and civilian personnel at Air Force Space Command and Space and Missile Systems Center.”

[ . . . . ]

Ray Kolibaba

“Basically we are nearly on cost for the OCX contract. The current contract value is $925M; the original cost estimate was $886M. We are driving forward on that and the Block 1 date or Ready to Operate (RTO) date. Right now, the customer team is working on finalizing a new enterprise schedule that will show the Program Management Directive dates. So, we don’t know the exact date the government envisions. I expect an official date either late this year or early next year. I encourage you to ask Colonel Gruber [U.S. Air Force GPS Directorate] this question, and maybe then we will also get an answer. We have given them our recommendations.

“Concerning sequestration, I am not worried. I believe we have a reasonable level of support from Congress to maintain and continue OCX. That doesn’t mean something won’t change. Our Washington folks tell us that OCX appears to be on solid footing. The Air Force FY13 Research, Development, Test & Evaluation budget request for OCX, to include Raytheon, support contractors, the GPS Directorate, Federally Funded Research and Development Centers and the like, was $371.6M, and the Continuing Resolution amount was $369.4M — given the current budget environment, that is strong Congressional support.”

[ . . . . . ]

“Successful completion of OCX will make a huge difference on a number of fronts. For instance, even though the FAA and DOT don’t have a whole lot of funding to ante up, we are going to make a difference in how they operate in the future. Some actions are transparent, but not all, as we implement their requirements and as we move forward with OCX.

“The sooner we implement the true capabilities of GPS on airliners and stop adhering only to the fixed air routes, the sooner we will start saving time and money with a vastly more efficient and flexible air routing system.

“So, from the civil side, there is certainly a difference, and when we bring other signals in they will be key for us, such as L2C, L5, and L1C. We have the solutions to do that with our receivers at this point in time, and I think it is fairly low-risk. Indeed that is probably another of my unofficial milestones.

“[On] the navigation side, GPS accuracy will noticeably improve, and we will use a new Kalman Filter. We are working the new Kalman filter with ITT Exelis and JPL to enhance capabilities. Couple that with better information assurance, increased integrity and predictability, along with system safety, and you have many of the key differences in the OCS system going forward.

[  . . . . . . ]

“We are required to support 40 PRNs at a minimum, with growth potential to 63 PRNs, and we may be able to support more. I’m not sure there is a limit on the system as such.”

In April of this year, Don Jewell wrote in his Defense PNT e-newsletter column:

“Most readers [of the report] won’t take the time to [dig deep]  and will assume that the OCX program is grossly over budget. It is not. In fact, to reach that extraordinary number, OCX cost overruns would need to have grown by 43 percent for each year since it was awarded, and that is ludicrous. According to Raytheon VP and OCX Program Manager Ray Kolibaba, the $3.695 billion number probably comes from including “…programmatic costs beyond OCX development costs and pessimistic projections from the government” that in my experience no acquisition agency, nor Congress for that matter, would ever include when determining true program cost adherence parameters.

Jewell makes the further point that OCX has grown in scope and schedule due in part to government change requests, mainly in the cyber and information assurance areas.

Where It Stands Now. Notwithstanding the optimism of the Raytheon OCX program manager six months ago, it is reasonable to expect that the GAO estimate of increased cost has drawn Congressional attention, and that in the current fiscal climate, the entire program may once again be imperiled.

Let’s all remember, brevity is the soul of wit.

GPS III Flexible Signal Generator. With completion of the Delta Preliminary Design Review for the GPS III satellites, Lockheed Martin and the U.S. Air Force announced that “an innovative new waveform generator permits the addition of new navigation signals after launch to upgrade the constellation without the need to launch new satellites.”

IGS Real-Time Service. The International GNSS Service, a worldwide federation of agencies involved in high-­precision GNSS applications, announced the launch of its Real-­Time Service (RTS). The RTS is a global-scale GNSS orbit and clock correction service that enables real-time precise point positioning and related applications requiring access to IGS low-latency products. The RTS is offered in beta as a GPS-­only service for the development and testing of applications.

QZSS Will Grow to Four. The Japanese government has ordered three navigation satellites from Mitsubishi Electric Corp. to expand the Quasi-Zenith Satellite System, currently orbiting the sole Michibiki. QZSS augments GPS navigation signals for users in the Asia-Pacific region. NEC Corporation has been awarded a contract for the QZSS ground control segment.

Real-Time PPP with Galileo. Fugro Seastar AS achieved this task within a week of all four Galileo satellites being activated. Fugro is now generating Galileo orbit and clock corrections, which can be used in conjunction with the Fugro G2 decimeter-level corrections associated with its GPS/GLONASS PPP service.

BeiDou Ground System Approved. The BeiDou Ground-Based Enhancement System (BGBES), a network of 30 ground stations, an operating system, and a precision positioning system, was approved by a Chinese government evaluation committee. The system is expected to improve BDS positioning accuracy to 2 centimeters horizontal and 5 centimeters vertical via tri-band real-time precision positioning technology, and to 1.5 meters with single-frequency differential navigation technology.

CNAV Test on GPS L2C and L5. The U.S. Air Force Space Command announced that CNAV capabilities on the GPS L2C and L5 signals will be tested in June. The civilian navigation message to be carried by modernized GPS will have similar data to the existing NAV message, but its structure will be different, with increased message bandwidth for greater information density. L2C and L5 users and receiver manufacturers are encouraged to review the test plan, provide comments, and participate in the evaluation process.

GPS at the Smithsonian. Brad Parkinson’s presentation, “GPS for Humanity — The Stealth Utility,” is now available as video on UStream.The talk helped introduce the new Smithsonian National Air and Space Museum exhibit, “Time and Navigation: The Untold Story of Getting from Here to There,” which is now open and free to the public in Washington, D.C.

Launch, deploy, and operate “22 satellites in less than 3 years.” That’s two satellites every three months, leading to a four-at-once launch in 2014. And that’s the challenge that Europe and the European Space Agency (ESA) now face.

This pointed call to action during the opening plenary of the European Navigation Conference (ENC) came from Didier Faivre, director of Galileo Programme and Navigation Related Activities at ESA. It was the only somber note sounded during the keynote speeches, which otherwise paraded the stirring recent accomplishments of the Galileo In-Orbit Validation (IOV) phase. IOV now concludes, and Galileo’s operational phase opens.

The ENC takes place in Vienna, Austria this week (April 23–25), hosted by the Austrian Institute of Navigation. Privately and informally, a handful of knowledgeable conference attendees expressed confidence that OHB System can furnish the completed satellites, at least, according to schedule. OHB System is the prime contractor for  construction of 22 Full Operational Capability (FOC) Galileo satellites and is responsible for developing the satellite bus and for integrating the satellites. Surrey Satellite Technology Ltd. (SSTL) is developing and constructing the navigation payload and  assisting OHB with final satellite assembly.

“Using only European tools and means, European ground infrastructure deployed on European territory, our conception, machine and design, is totally validated,” stated Faivre, referring to the recent Galileo-only positioning fix by ESA. The March 12, 2013, event marks “the end of the beginning,” and culminates 12 years of intense work at all levels of European industry.

“Europe is at par with GPS” with performance as expected. “I hope that soon our U.S. colleagues will be jealous of our performance,” Faivre stated, implying yet again the persistent Galileo claim that the system will be more accurate than GPS. He returned to this theme with reference to Fugro’s accomplishment of real-time precise point positioning at the centimeter level.

He acknowledged that “It’s a technological competition with the United States, Russia, and China,” even though all may be friendly and collegial.

In that competitive light, “the success of Galileo will be measured by the number of users,” and not by the number of satellites, or the degree of accuracy, or the strength of the signal.

Previously, the ENC audience had heard from Ingolf Schädler that “Europe has closed the gap with the technological superpowers,” in what “may be the most complex invention ever of mankind, the system of navigation that is GNSS.” He also made a proud reference to Austrian-produced signal generators aboard Galileo’s orbiting IOV satellites. Schädler is the deputy director general of innovation for the Austrian federal Ministry for Transport, Innovation and Technology.

“We have reached cruising speed,” announced the third keynote speaker, Carlo des Dorides of the European GNSS Agency (GSA). He was referring explicitly to the re-positioning of the GSA headquarters from Brussels to Prague, but the remarks reverberated to the Galileo program as a whole.

David Blanchard, deputy head of unit, EU Satellite Navigation Programmes for the European Commission, quoted an unnamed U.S. publication: “With the capability to make a position fix from four signal-broadcasting satellites, we can now say that Galileo has truly arrived.”

That statement appeared in the May 2013 GPS World, an issue of the magazine that was distributed in conference bags to all attendees at the ENC.

Blanchard then shifted the focus slightly from Galileo, to Galileo together with the European Geostationary Navigation Overlay Service (EGNOS), Europe’s satellite-based augmentation service that also broadcasts GPS corrections. “We have to make sure that all the capabilities afforded by EGNOS are realized.” He also made strong references to the EGNOS Data Access Service (EDAS).

Blanchard cited a current ongoing study that shows that 6 to 7 percent of European gross domestic product (GDP) is dependent upon GNSS.

“A gold mine within arm’s reach of European industry” was how Gard Ueland, head of Galileo Services, characterized the present situation. “Development of European downstream market is crucial; it also has to bring more benefits to European society.” Galileo Services will host a workshop of  industry stakeholders in late October, at the OHB System premises in Bremen, Germany. Watch GPS World Events calendar and news for an announcement with specific dates.

Having attained altitude and cruising speed, the Galileo program must now shift to warp speed to hit its goals on time: 18 satellites in orbit by the end of 2014, and a total of 26 by the end of 2015. Early services by the end of 2014, and full services in 2016. Stable, continuous services, as Blanchard emphasized.

Better go to overdrive.

The April 18 webinar is free, but you must register beforehand. A downloadable file of the webinar will be available roughly one week afterwards, in case you miss the live presentation. Speakers include Khaled Dessouky from TechnoCom Corporation, a company that supervised the trials; Ganesh Pattabiraman from NextNav and Norm Shaw from Polaris Wireless, two companies whose technologies underwent rigorous testing in the trials; and Greg Turetzky from CSR, a company closely involved in the process.

Testing Overview

Conducted by the Communications Security, Reliability, and Interoperability Council (CSRIC) of the Federal Communications Commission (FCC), Working Group 3 (WG3), the tests trialled thousands of attempted location fixes in four representative morphologies (dense urban, urban, suburban, rural) and various building types.

The massive R&D movement focus on consumer-level applications, that is, cell phones, but this work will also ultimately affect professional and high-precision uses of GNSS. Those involved in machine control for warehousing, industrial assembly, indoor and even underground mapping, construction both above- and underground, underground mining, utility work, and even forestry will find this of particular interest — any activity in areas where sky-view is limited or negligible.

Test Fixture (cart) used during indoor testing.

Today, well more than half of mobile phone calls are made inside buildings. The number of emergency calls roughly parallels that, and both figures are only projected to rise. The FCC has a clear mandate to bring E-911 capability to indoor calls.

The 2001 regulations governing such emergency calls required that both landlines and cellphones should provide the location of callers to within specific accuracy levels. Location information was to be sent transparently to public safety answering points (PSAPs), to dispatch fire/rescue/police personnel to the source the 911 call, and not just to the right street address, but to the right floor of a multi-storied building. That’s the driver for all this.

Widespread application of successful technology/ies meeting the indoor requirement, once determined, is the key to significant revenue for many parties, not least of them GNSS manufacturers and location-based services (LBS) providers.

GPS and augmented GPS technologies were only part of the cellphone solution, and other implementations included use of the cell signal itself along with an extensive database which can contain amongst other things signal attributes and network asset locations.

The WG-3 Locations Based Services (LBS) sub-group set about finding what technologies exist, how well they work and how they could be applied to E-911. Click here for the full report.

In the tests, Polaris Wireless used an RF pattern-matching/fingerprinting technique, Qualcomm used a hybrid assisted-GPS (A-GPS)/advanced forward link trilateration (AFLT) system, and NextNav used wireless beacon technology.

WG3 selected the San Francisco Bay Area for the Stage-1 Indoor Test Bed. The methodology centered on indoor testing in sample buildings within the most common wireless use environments, called morphologies: dense urban, urban, suburban, and rural.

Dense urban: Bldg. 2: One Front Street, San Francisco, California.

Urban: Bldg. 18: Super 8 Motel on O’Farrell St., San Francisco, California.

Suburban: Bldg. 8: 861 Shirley Avenue (house), Sunnyvale.

Rural: Bldg. 13: Gilroy Gaits, Beige Stable Building, Hollister, California.

Polygons surrounding areas containing 19 buildings were selected; the distribution of buildings tested was 6 dense urban, 5 urban, 6 suburban and 2 rural. 75 test points were selected by TechnoCom within these 19 buildings. Statistically significant samples of stationary test calls were placed from each test point using multiple test devices for each of the 3 location technologies under test by NextNav, Polaris Wireless, and Qualcomm.

More than 13,000 valid test calls were collected across the test points for each of the three technologies. Broad, representative wireless industry participation in the test bed meant that Polaris’ results were aggregated over AT&T’s and T-Mobile’s networks; Qualcomm’s results were aggregated over Sprint’s and Verizon’s networks; and NextNav operated essentially as a standalone overlay location network.

A certified land surveyor provided indoor ground-truth accuracy to compare test-call locations. The certified accuracy was +/-1 cm horizontal and +/-2 cm vertical.

The test results show the location-performance attributes under test: horizontal location accuracy, vertical accuracy, yield, time to first fix (TTFF), and reported uncertainty.

NextNav Summary Indoor Accuracy Statistics.

Polaris Summary Indoor Accuracy Statistics.

Qualcomm Summary Indoor Accuracy Statistics.

Dense Urban Environment

Satellite signals (in this instance, GPS) have, of course, significant challenges in penetrating large buildings. Consequently, AGPS fall-back modes, such as AFLT, were experienced frequently. Accuracy degraded as expected when GPS fixes were not attained. While a surprising proportion of hybrid fixes were experienced, even at test points where one would not expect a satellite signal to penetrate, the quality of the hybrid fixes was in general significantly degraded compared to GPS fixes.

RF finger-printing experienced its best performance in the dense urban setting. This is probably a combination of a confined environment that could be extensively calibrated and many RF cell sites and handoff boundaries that could be leveraged in creating a good RF fingerprint map of the dense urban center.

The best observed performance in the dense urban setting was that of the dedicated terrestrial (beacon) location system — a new infrastructure. However, due to multipath, location fixes that may be relatively close in absolute distance (for example, 40 meters away) are often located in a building across the street, in a neighboring building, or even across a few blocks from the test point.

Urban Environment

Each individual test building in the urban morphology produced different challenges, and the three technologies under test met them in varying degrees.

A major-league baseball stadium created a situation where AGPS fallback fixes could be very far away due to the exposed RF propagation outside the structure in which the test points were located. Stadium structure created challenges to RF fingerprinting at some test points.

A convention center created in some cases an environment that was deep indoors but with very strong cellular signal from cell sites inside the building. This made the beacon-based location system perform poorer than in most other test points, since attenuation to different directions in the outside world was particularly strong in those scenarios. AGPS and RF fingerprinting relied on the cell sites inside the structure to create adequate location fixes.

An older building of comparatively heavy construction, with a large atrium in its middle, produced widely varying results based on distance from windows or the atrium. Again, the phenomenon of apparent location in a building across the street was seen for both NextNav and Qualcomm. RF fingerprinting fixes appeared to cluster about the larger reflectors in this urban corner of San Francisco, which happened to be mostly across the streets from the target building.

A motel building demonstrated the unique challenge with indoor location: absolute distances (like 50 or 150 meters) which may have meant much in assessing outdoor performance mean less for the indoors, since emergency dispatch to the wrong building or even the wrong block could be easily encountered at those distances. A location across the street is certainly better than one a few or many blocks away but it may still leave some human expectations unmet.

A tall condominium building in a (non-dense) urban downtown San Jose created relatively poor AGPS performance, uneven beacon system performance, and RF fingerprinting performance that degraded with the height of the test point. All of the above factors related to each of the urban buildings, combined with a generally lower cell site density for fall back (than in dense urban), resulted ultimately in an aggregate urban performance that is slightly worse than the dense urban performance.

Suburban Environment

The effect of smaller buildings with lighter construction and more spacing between buildings quickly became evident. Outstanding GPS performance, almost as good as outdoors, can be achieved inside single-story homes. Similarly outstanding performance is achieved on average by the beacon-based location technology under similar circumstances. RF fingerprinting appears to suffer from performance degradation compared to more dense morphologies in the city.

The AGPS performance predictably changes as the suburban buildings become bigger and higher. The terrestrial beacon-based network continues to perform well in the larger suburban. RF finger-printing shows some enhancement relative to the smaller suburban buildings, but still shows most of the location fixes along the roads, highways or reflecting buildings.

Rural Environment

Large one-story structures with metal roofs limited the available number of satellite signals available for trilateration. In these cases more hybrid fixes were experienced with a concomitant increase in the spread of the location fixes about the true location. The performance of the beacon-based network was less impacted by the metallic roof (since that roof had more impact on sky visibility rather than on side visibility towards terrestrial beacons). Consequently the performance was somewhat better than for AGPS. The performance of the beacon-based network would of course depend on the density of its deployed beacons covering the rural area, which was sufficient in the case of the rural test polygon.

RF finger-printing showed reduced performance relative to the suburban environment due to the large spacing between surveyed roads (where calibration is done) and the rural structures as well as the lower density of cell sites.

Conclusion

Finally, the report concludes: “Stage-1 of the test bed contained in the end only three technologies to test. With the complexity of the task at hand, this created a good learning opportunity for both CSRIC WG3 members and the test house. However, there are a number of technologies that are either in use for location based services (LBS) or that are emerging which should be evaluated for their potential to contribute to the improvement of indoor wireless E911.

“Indoor wireless E911 is a critical public safety issue that will only increase.”

One key factor that the report does not at all address is relative cost of implementing these respective solutions. The same can be said for timeline. While some observers have concluded that “NextNav came out on top,” this solution in particular can be presumed to face much greater challenges for full or nationwide implementation than the other two, which rely largely on already existing infrastructures.

Another round of E-911 test-bed activities will ensue once funding and management issues are resolved. See CSRIC WG 3 LBS Subgroup member Greg Turetzky’s “Expert Advice” column from GPS World for perspective and a forward look.

Once again, for an up-close and personal look at the CSRIC Bay Area indoor tests, register beforehand here for Thursday’s webinar, April 18. A downloadable file of the webinar will be available roughly two weeks afterwards, in case you miss the live presentation.

My acquaintance with the system began in July 2000, when I joined the staff of GPS World and received my first assignment, editing an article about GPS-bearing carrier pigeons in the sister publication Galileo’s World, from founding editor Glen Gibbons. We published Galileo’s World quarterly from 2000 to 2002, chronicling the ups and downs, forward steps and back, of the European GNSS. Unless you counted EGNOS — really telecom satellites with a piggyback SBAS payload — Galileo had no space vehicles as yet, but did encompass plenty of political and financial maneuvering, rhetoric, market projections, international negotiations, and technical blueprints. In short, the stuff of news. For application stories in the magazine, we filled with European uses of GPS, all of which would eventually integrate Galileo as well.

In 2002, a UK-based travel agency of the same name began to assert its legal possession of the name Galileo, and sent a cease-and-desist shot across the bows to the corporate ownership of the two magazines, and to the European Union. The EU felt it had sufficient legal clout or standing of some kind, for it neither desisted nor renamed its space program. But our counsel at the time instructed us to quietly fold up our tent and steal away. The impending battle wasn’t worth our stake.

And so Galileo’s World sadly ceased publication. Not for lack of interest, or support, or commitment. But because of someone else’s greed or turf belligerence in a completely unrelated market. Such is the way of the global economy.

We have covered every step of Galileo’s way, technically, economically, and politically, in the pages of GPS World. Occasionally we ponder calling ourselves GNSS World, or even PNT World. But the brand, like the satnav system it is named after, is just so strong, it would be foolhardy to walk away from it, at this point in time at least.

We continue to support European satnav progress at each successive stage. And so we say yet again: Welcome, Galileo!

Measurements of individual Galileo horizontal position fixes performed for the first time using the four Galileo satellites in orbit plus the worldwide ground system between 1000 and 11:00 CET on Tuesday 12 March 2013, showing an overall horizontal accuracy over ESTEC in Noordwijk, the Netherlands, of 6.3 m.

Galileo Logs First Autonomous Fix; Galileo over Canada (By James T. Curran, Mark Petovello, and Gérard Lachapelle); and Indoor Nav: Early Steps towards FCC Standards

Galileo Logs First Autonomous Fix

Entitling its release “From Orbit with Love,” the European Space Agency (ESA) announced March 12 that the four current satellites of the Galileo constellation achieved their first autonomous position fix. The feat was replicated by the NavSAS group of Politecnico di Torino, by GNSS manufacturer Septentrio, and by a University of Calgrary team as the four satellites appeared over North America.

The obtained accuracy lies in the 10-meter range, according to ESA, adding that this fulfills expectations, considering the infrastructure is only partly deployed. The fix was obtained by ESA’s Netherlands navigation lab, using the four satellites, launched in October 2011 and 2012, and the Galileo programme’s ground infrastructure: control centers in Italy and Germany and a global network of ground stations.

With only four satellites for the time being, the full Galileo constellation is visible at the same time for a maximum two to three hours daily. This frequency will increase as more satellites join the constellation in orbit, along with extra ground stations coming online, for Galileo’s early services to start at the end of 2014.

With the validation testing activities under way, users might experience breaks in the content of the navigation messages being broadcast, said ESA. In the coming months the messages will be further elaborated to define the offset between Galileo System Time and Coordinated Universal Time (UTC), enabling Galileo to be relied on for precision timing applications, as well as the Galileo to GPS Time Offset, ensuring interoperability with GPS.

NavSAS Confirmation. Almost simultaneously with the ESA announcement, the NavSAS group of Politecnico di Torino and Istituto Superiore Mario Boella in Turin, Italy, also achieved a position fix using the signals of the four In-Orbit Validation satellites (PFM, FM2, FM3, FM4). NavSAS researchers computed the positions using full software receivers developed by the team.

Septentrio, Too. Septentrio became the first receiver manufacturer to report an autonomous real-time position calculation using Galileo IOV satellites with its own standard commercial receiver. The company based in Leuven, Belgium announced on March 12 that it performed  standalone position calculated from in-orbit navigation messages using a standard PolaRx4 GNSS receiver equipped with commercially released firmware.

This achievement was followed by a further Septentrio release stating performance of what it believes to be the first 4-constellation PVT by a standard commercial receiver, on March 12 at approximately 10:35 UTC.

The milestone in all three accounts is that it is Galileo-only real-time positioning. Galileo positioning in post-processing mode was described by authors from the Technische Universität München and the German Space Operations Center, in a GPS World account, February 2012 issue.

Galileo over Canada

By James T. Curran, Mark Petovello, and Gérard Lachapelle

Within a day of activation over Europe, Galileo satellites were visible over North America. The PLAN Group of the University of Calgary captured and processed signals from Galileo PRN 11, 12, and 19 on E1B/C. The PLAN software GSNRx  simultaneously tracked GPS L1 and GLONASS L1 for combined solutions in real time.

The Galileo navigation message on E1B stated that the satellite health status is flagged as E1BHS=3 meaning “Signal Component currently in Test” and the data validity status is flagged as E1BDVS=1 meaning “Working without guarantee.” Current Galileo-ready commercial receivers may automatically discard measurements from a satellites broadcasting such messages. Parsing the received words in the I/NAV message, more than 50 percent were of type 0, although all words (types 0 to 10) were decoded at some point during the test.

Figure 1. 2D position errors.

Data was collected using a roof-mounted NovAtel 702GG antenna and an in-house two-channel digitizing front-end clocked by a high quality OCXO, in addition to a three-channel National Instruments front-end for post-processing. The two-channel intermediate frequency data was streamed live to a laptop computer for real-time processing with GSNRx. The GPS and GLONASS signals were tracked using a Kalman-filter-based tracking strategy while the Galileo signals were tracked using a specialized data-pilot algorithm.

Pseudorange and Doppler observations were extracted from the tracking strategies at a rate of 2 Hz. Single-frequency single-point position solutions were then computed for each of the three systems, each of the three pairs of systems and for the full combined Galileo-GLONASS-GPS. In the case of the three-satellite Galileo solution, the height was held fixed. Figure 1 shows 2D position errors with respect to antenna ITRF coordinates. Departures of the solutions involving GLONASS are likely due to orbital biases, given location of Calgary with respect to GLONASS ground stations.

Figure 2. Pseudorange residuals.

Next, by fixing the known position in the solution and solving only for the three clock biases, accurate pseudorange residuals were computed and are shown Figure 2. Galileo PRN 19, launched a year later than PRN 11 and 12, exhibits larger residuals, perhaps attributable to ephemeris or orbital errors. The overall results show very good consistency of the Galileo results and the PLAN Group equipment and GSNRx receiver.

Indoor Nav: Early Steps towards FCC Standards

The Federal Communications Commission (FCC) on March 14 released two reports from its Communications Security, Reliability, and Interoperability Council (CSRIC): the “Indoor Location Test Bed Report,” and “Leveraging LBS and Emerging Location Technologies for Indoor Wireless E9-1-1.”
They report on Bay Area tests of technology from NextNav, Polaris Wireless, and Qualcomm, in four representative morphologies (dense urban, urban, suburban, rural) and various building types. They are available online, via www.gpsworld.com/csric, are the subject of an Expert Advice column (see page 10), and will be more fully discussed in May issue.  For now, this summary from the first-named report:

“Seven location vendors/technologies began the process to demonstrate their performance indoors through the common test bed, but only three completed the process. Of these three, two technologies (AGPS/AFLT and RF Fingerprinting) are already in common use for emergency services, while the third (metropolitan beacons) is not yet commercially available. However all technologies tested demonstrated relativity high yield and various levels of accuracy in indoor environments.

“Significant standards work is required for practical implementation of many emerging location technologies for emergency services use.

“Many positioning methods require handset modifications. Integration of these modified handsets into the subscriber base, once the location technology is commercially available, will take years to complete.

“Progress has been made in the ability to achieve significantly improved search rings in both a horizontal and vertical dimension. However, even the best location technologies tested have not proven the ability to consistently identify the specific building and floor, which represents the required performance to meet Public Safety’s expressed needs. This is not likely to change over the next 12–24 months. Various technologies have projected improved performance in the future, but none of those claims have yet been proven through the test bed process. It is hoped that such technologies would be tested and validated in future test bed campaigns.”

An April 16 GPS World Webinar covers this topic with test participants. Registration is free.