GPS World

Tag: Satelles

  • PNT Roundup: Iridium constellation provides low-Earth orbit satnav service

    PNT Roundup: Iridium constellation provides low-Earth orbit satnav service

    Iridium satellite. (Image: Iridium)
    Iridium satellite. (Image: Iridium)

    A strategic alliance announced on Dec. 15 between Orolia and Satelles includes product development and go-to-market activities of positioning, navigation and timing (PNT) solutions provided by the Iridium satellite constellation, independent of GPS/GNSS signals. The companies intend to provide PNT solutions to military, defense, government and commercial customers worldwide.

    Orolia, the parent of GNSS-active companies Spectracom and Spectratime, among others, has formed a strategic alliance, including an equity investment, with Satelles Inc. to develop, market and sell PNT solutions based on Satelles’ satellite time and location (STL) signal technology.

    STL is a unique space-based PNT technology that provides location and timing data independent from traditional GPS and other GNSS satellite signals. By using STL, Orolia’s Spectracom and McMurdo solutions will, according to the company, be less susceptible to vulnerabilities such as spoofing, interference and jamming that are associated with GPS/GNSS.

    Based on the low-Earth orbit (LEO) Iridium satellite constellation, STL signals are up to 1,000 times stronger than GPS/GNSS; this signal strength, due in part to the constellation’s closer proximity to users, helps to prevent jamming and enables signal reach into buildings and other difficult locations. STL’s additional cryptographic security also ensures performance, productivity and security.

    For further background on Iridium, see GPS World’s June 2016 Defense PNT column, “Iridium and GPS revisited: A new PNT solution on the horizon?” Projected applications and use cases include energy/utility grids, enterprise data networks including financial systems, maritime/aviation navigation, fleet/asset tracking management, search and rescue, and data center management.

    Many highly sensitive military, defense, government and commercial applications and operations require accurate and reliable PNT data. Today, these applications rely on signals from GPS/GNSS satellites. There are instances, however, where GPS/GNSS signal strength and security are not sufficient and prone to signal disruption. For these cases, the companies jointly state, STL can be used as a secure signal of opportunity to complement GPS/GNSS, making the applications more accurate and secure, and less prone to interference and attack.

    “There is a growing need for precise and robust positioning, navigation and timing information especially in business-critical, high-risk and life-saving operations,” said Jean-Yves Courtois, Orolia CEO. “By augmenting Orolia’s GPS/GNSS-based solutions with Satelles’ STL technology, we will have the industry’s first essentially fail-safe, resilient PNT solution. This breakthrough offering will be ideal for mission-critical applications in which the smallest discrepancy in PNT data accuracy, availability and stability can produce a network outage, a system crash or a loss of life.”

    Signal strength, availability

    The technical advantages provided by adding ranging satellites in low-Earth orbit (LEO) to the GNSS satellites in medium-Earth orbit (MEO) were explored in a 2012 Institute of Navigation paper by Per Enge, Bert Ferrell, David Whelan, Greg Gutt and David Lawrence. GPS World plans to publish an updated version of that paper, with key new material on current STL performance statistics, in an upcoming issue.

    Briefly, the paper concluded that “Due to their proximity, signals received from LEO are approximately 30 dB stronger than the signals from MEO. Indeed, we show data collected inside an industrial-strength metal storage container. The power of a LEO signal received inside the container is approximately equal to the power of a GPS signal received under the open sky. On the other hand, LEO proximity also dictates that only a few Iridium satellites are in view of the ground-based user. We show typical examples where six to 11 GPS satellites are joined by one or two LEO satellites.”

    The authors then examine the effect of the swift mean motion of LEO satellites, analyzing the ability to whiten multipath based on the rapid motion of the line-of-sight vectors from the user to the LEO satellites. In sharp contrast to MEO, the LEO satellites attenuate errors due to multipath solely based on satellite motion, and do not require user motion. They also analyze Doppler-based positioningvusing the rapid mean motion of the LEO satellites. The Doppler shift projects onto the line-of-sight vectors from the user to the LEO satellites. Over 100 or 200 seconds, this projection is a sharp function of the user location, and this connection enables Doppler-based positioning similar to the Transit satellite system. The authors’ analysis shows that position accuracies of 5 meters can be based on noncoherent code tracking of the LEO plus GPS signals.

    This paper also discusses the broadcast of UTC time to sites with known locations, describing experimental results with absolute time accuracies of one microsecond. The broadcast of high-accuracy frequency from LEO would enable a high-accuracy hot clock to replace the relatively low-quality oscillator in GNSS receivers, allowing longer coherent and non-coherent averaging times and improving the sensitivity of GNSS receivers by several decibels. Many other navigation applications would benefit from one LEO satellite in view, the authors assert.

    Market view from operator’s CEO

    “We are a manufacturer and integrator of timing equipment,” Orolia CEO Jean-Yves Courtois told GPS World. Orolia is the parent company of GPS/GNSS product and service providers Spectracom, McMurdo and Spectratime. “This new STL service is not fully commercialized yet, but it’s operational and it can be tested. Receivers are available and can be integrated into our equipment.

    “The timing signal is very accurate and close enough to GPS for most timing applications, although the positioning accuracy is lower than what GPS users are accustomed to. It is an augmentation for timing primarily, and secondarily for positioning,” Courtois continued.

    “In terms of timing accuracy, it provides on the order of tenths of microseconds in accuracy, and this covers a lot of timing applications. This is an ideal timing backup or augmentation of GPS. In positioning it’s closer to 50 meters or more, much better for fixed objects than for mobile objects. The faster the vehicle, the lower the positioning accuracy. It’s not directly usable for GPS applications that require a few meters’ accuracy, but it can be associated with inertial navigation for much better results.

    “The STL signal penetrates buildings well, it has unique features, and it performs at a high level. The signal is encrypted, so you have to subscribe to a service to receive a key, allowing access to the signal. Applications are developing based on equipment that will be STL-enabled. For the user it will be transparent. The user will have a different antenna.

    “We are also active in tracking and emergency location devices, where this is also of interest. It has some authentication capability, to guarantee that the person who accesses the signal is in the location that he pretends to be.

    “For customers to be able to use this service, there is some integration work to be done, some dedicated STL receivers to integrate into our current hardware set up, and software modifications. We are ready to work with government and defense organizations and other new clients. Our basic interest is to add some robustness to our equipment for our current customers, and then of course to develop new customers worldwide.”

    Grab It’n’Go Drive-By Shopping

    Four years ago, retail giant Amazon, a leader in the elimination of human interaction, started to explore what shopping would look like if you could walk into a store, grab what you want, and leave. In early December, the company rolled out its new vision: Amazon Go.

    Currently in private beta testing in Seattle and scheduled to open to the public in early 2017, the system employs a fusion of sensor technologies including RFID to detect when a shopper takes an item from the shelf, sync the data to the shopper’s handheld device, sense when the shopper leaves the store area, then charge all collected items to the shopper’s Amazon account. No muss, no fuss.

    The company is keeping a tight lid on exactly how its system works, but earlier patent filings give some description of the confluence of sensor data.

    “In some implementations, data from other input devices may be used to assist in determining the identity of items picked and/or placed in inventory locations. For example, if it is determined that an item is placed into an inventory location, in addition to image analysis, a weight of the item may be determined based on data received from a scale, pressure sensor, load cell, etc., located at the inventory location. … By combining multiple inputs, a higher confidence score can be generated increasing the probability that the identified item matches the item actually picked from the inventory location and/or placed at the inventory location.”

  • New defense signals offered, new defense editor sought

    New defense signals offered, new defense editor sought

    Two important new signals — or rather, one signal and one group of signals — became available for military users worldwide last week. Satelles made an exciting announcement of what amounts to a new dimension in satnav: a whole new constellation in low-Earth orbit, bringing global coverage and most critically, a signal strength hitherto unknown to GNSS users. The satellite time and location (STL) has primary application in the timing realm, which is vital in many applications.

    Higher in the sky, Europe’s GNSS satellites constituting the Galileo system officially began offering their services, and the multiple frequencies available here mean robustness, greater availability in obstructed environments, and — some say, though this is controversial — greater positioning accuracy, largely through more precise timing onboard.

    Meanwhile, GPS World seeks a new defense editor for this column, and adopting the concept of “promoting from within,” now turns to its readership for interested parties to volunteer.

    A New SatNav That’s Not GNSS

    A strategic alliance announced on Dec. 15 between companies Orolia and Satelles includes will provide positioning, navigation and timing (PNT) solutions provided by the Iridium satellite constellation, independent of GPS/GNSS signals. The companies intend to provide PNT solutions to military, defense, government and commercial customers worldwide. Their new satellite timing and location (STL) service can supply much-needed robustness to GPS-dependent operations.

    Orolia, the parent of GNSS-active companies Spectracomm, McMurdo, and  Spectratime, has extensive experience in the defense realm. The company says it is #1 worldwide in the manufacture of military beacons outside the U.S. with a 60% market share, and #2 within the U.S., and that it is the first-ranked provider of Medium-altitude Earth Orbit Search and Rescue system (MEOSAR) worldwide.  In partnership with Satelles, it will provide the STL service independent from traditional GPS and other GNSS satellite signals. STL is reported to be less susceptible to vulnerabilities such as spoofing, interference and jamming that are associated with GPS/GNSS — and the stronger signal penetrates buildings where GPS/GNSS cannot reach.

    Iridium satellite, courtesy Iridium.

    Iridium satellite, courtesy Iridium.

    Based on the low-Earth orbit (LEO) Iridium satellite constellation, STL signals are up to 1,000 times stronger than GPS/GNSS; this signal strength, due in part to the constellation’s closer proximity to users, helps to prevent jamming and enables signal reach into buildings and other difficult locations. STL’s additional cryptographic security also enhances performance, productivity and security.

    For further background on Iridium, see the June 2016 Defense PNT column by Don Jewell,“Iridium and GPS revisited: A new PNT solution on the horizon?”

    Projected key applications and use cases include energy/utility grids, enterprise data networks including financial systems, maritime/aviation navigation, fleet/asset tracking management, search and rescue and data center management.

    “The timing signal is very accurate and close enough to GPS for most timing applications, although the positioning accuracy is lower than what GPS users are used to,” said Orolia CTO Jean-Yves Courtois. “It is an augmentation for timing primarily, and secondarily for positioning.”

    “In terms of timing accuracy, it provides on the order of tenths of microseconds in accuracy, and this covers a lot of timing applications, very familiar to us and to our customers. This is an ideal timing backup or augmentation of GPS. As number 2 worldwide in high-precision timing, we know this market and its applications very well.”

    “In positioning it’s closer to fifty meters or more. Much better for fixed objects than for mobile objects. The more mobile, the faster the vehicle, then the lower the positioning accuracy. It’s not directly usable for GPS applications that require a few meters accuracy, but it can be associated with inertial navigation for much better results.”

    “The signal is encrypted, so you have to subscribe to a service to receive a key, allowing access to the signal. Applications are developing based on equipment that will be STL-enabled. For the user it will be transparent. The user will have a different antenna.”

    “We are also active in tracking and emergency location devices, where this is also of interest. It has some authentication capability, to guarantee that the person who accesses the signal is in the location that he pretends to be.”

    Galileo, live at last!

    Also on Dec. 15, the European Commission issued the Galileo Initial Services Declaration. The Declaration of Initial Services means that the Galileo satellites and ground infrastructure are now operationally ready. These signals will be highly accurate but not available all the time, since the constellation is not yet complete and users cannot always count on four satellites being visible at one time at all points on the Earth.

    Galileo has a significant role to play in military operations. It adds multiple frequencies to the GNSS palette, important for resistance to jamming. It adds satellites, and will add more in the new future, very important for signal availability.  And its Public Regulated Service (PRS) is specifically designed with special features for security, defense and military operations.

    I attended a GNSS Symposium recently in Australia where an academic expert repeated the oft-made assertion that Galileo is the only GNSS that is civil-designed and civil-controlled. At which point an industry expert leaned over, grabbed the microphone and growled “Yeah, right.”

    No matter how you look at it, Galileo add important benefits to GPS for  the suitably equipped warfighter.

    This Newsletter Enters a New Era

    Beginning in January 2017, this Defense PNT newsletter will combine with our GeoIntelligence Insider e-newsletter to offer broad coverage of both hardware and software matters, driven by GPS/GNSS, and enhancing the capabilities of security, defense, military and other government forces. Readers of both newsletters will receive the new combined edition as a matter of course.

    Many readers will know of  the recent passing of Don Jewell, the longtime editor of Defense PNT.  We must soldier on, and GPS World hereby extends an invitation to readers of this newsletter — many of whom, we know, are military experts in your own right — who may wish to volunteer to fill Don’s position.  Please write to [email protected] to request details, and please provide a brief outline of your background and experience.

    Until next time,

    Happy Navigating.

  • New SatNav offerings come to market via STL service

    Pursuant to a recent announcement of new PNT solutions independent of GPS/GNSS signals, provided via the Iridium constellation, GPS World talked with Jean-Yves Courtois, CEO of Orolia. Orolia has partnered with Satelles to bring new PNT products and services to the global market, with a focus on military, and defense, government and commercial customers worldwide.

    Jean-Yves Courtois, CEO of Orolia
    Jean-Yves Courtois, CEO of Orolia.

    “We are a manufacturer and integrator of timing equipment,” Courtois said. Orolia is the parent company of GPS/GNSS product and service providers Spectracom, McMurdo and Spectratime. “This new STL service is not fully commercialized yet, but it’s operational and it can be tested. Receivers are available and can be integrated into our equipment.

    “The timing signal is very accurate and close enough to GPS for most timing applications, although the positioning accuracy is lower than what GPS users are used to. It is an augmentation for timing primarily, and secondarily for positioning.

    “In terms of timing accuracy, it provides on the order of tenths of microseconds in accuracy, and this covers a lot of timing applications, very familiar to us and to our customers. This is an ideal timing backup or augmentation of GPS. As number 2 worldwide in high-precision timing, we know this market and its applications very well.”

    The STL signal strength is much greater than GNSS because the LEO satellites are much closer. (slide courtesy Satelles)
    The STL signal strength is much greater than GNSS because the LEO satellites are much closer. (slide courtesy Satelles)

    Because the signal providing the satellite time and location (STL) service emanates from low-Earth orbit (LEO) satellites, its strength is much greater than GPS and other GNSS signals. Among its key characteristics: it gets good reception inside buildings and beneath other obstructions.

    “The STL signal works very well,” Courtois continued. “We were surprised. Satelles is very conservative in their statements, and we got better results than they promised in our tests. They under-promised and over-delivered. It penetrates buildings well, it has unique features and it performs at a high level. So we decided to invest in it. All our engineers are excited about it!

    “In positioning it’s closer to fifty meters or more. Much better for fixed objects than for mobile objects. The more mobile, the faster the vehicle, then the lower the positioning accuracy. It’s not directly usable for GPS applications that require a few meters accuracy, but it can be associated with inertial navigation for much better results.

    “The signal is encrypted, so you have to subscribe to a service to receive a key, allowing access to the signal.

    “Applications are developing based on equipment that will be STL-enabled. For the user it will be transparent. The user will have a different antenna.

    “We are also active in tracking and emergency location devices, where this is also of interest. It has some authentication capability, to guarantee that the person who accesses the signal is in the location that he pretends to be.”

    “For customers to be able to use this service, there is some integration work to be done, some dedicated STL receivers to integrate into our current hardware set up, and software modifications. Our engineers are ready, we are all ready to work with government and defense organizations and other new clients.”

    “Our basic interest is to add some robustness to our equipment for our current customers, and then of course to develop new customers worldwide.”

     

     

     

  • Orolia fortifies resilient PNT with Satelles satellite time and location signal

    Orolia fortifies resilient PNT with Satelles satellite time and location signal

    A strategic alliance announced on Dec. 15 between Orolia and Satelles includes product development and go-to-market activities of positioning, navigation and timing (PNT) solutions provided by the Iridium satellite constellation, independent of GPS/GNSS signals. The companies intend to provide PNT solutions to military, defense, government and commercial customers worldwide.

    Orolia, the parent of GNSS-active companies Spectracom and Spectratime, among others, announced that it has formed a strategic alliance, including an equity investment with Satelles Inc. to develop, market and sell PNT solutions based on Satelles’ satellite time and location (STL) signal technology. STL is a unique space-based PNT technology that provides location and timing data independent from traditional GPS and other GNSS satellite signals. By using STL, Orolia’s Spectracom and McMurdo solutions will, according to the company, be less susceptible to vulnerabilities such as spoofing, interference and jamming that are associated with GPS/GNSS.

    Iridium satellite, courtesy Iridium.
    Iridium satellite, courtesy Iridium.

    Based on the low-Earth orbit (LEO) Iridium satellite constellation, STL signals are up to 1,000 times stronger than GPS/GNSS; this signal strength, due in part to the constellation’s closer proximity to users, helps to prevent jamming and enables signal reach into buildings and other difficult locations. STL’s additional cryptographic security also ensures performance, productivity and security.

    For further background on Iridium, see “Iridium and GPS revisited: A new PNT solution on the horizon?“, the June 2016 Defense PNT column by Don Jewell.

    Projected key applications and use cases include energy/utility grids, enterprise data networks including financial systems, maritime/aviation navigation, fleet/asset tracking management, search and rescue and data center management. Further details on planned projects and products of the Orolia-Satelles partnership will be posted to this site in a follow-up story in coming days.

    Many highly sensitive military, defense, government and commercial applications and operations require accurate and reliable PNT data. Today, these applications rely on signals from GPS/GNSS satellites. There are instances, however, where GPS/GNSS signal strength and security are not sufficient and prone to signal disruption. For these cases, the companies jointly state, STL can be used as a secure signal of opportunity to complement GPS/GNSS, making the applications more accurate and secure and less prone to interference and attack.

    “In today’s increasingly dynamic and mobile world, there is a growing need for precise and robust positioning, navigation and timing information especially in business-critical, high risk and life-saving operations,” said Jean-Yves Courtois, Orolia CEO. “By augmenting Orolia’s market-leading GPS/GNSS-based solutions with Satelles’ STL technology, we will have the industry’s first essentially fail-safe, resilient PNT solution. This breakthrough offering will be ideal for mission critical applications in which the smallest of discrepancies in PNT data accuracy, availability and stability can result in a network outage, a system crash or a loss of life.”

    “Satelles’ pioneering role in STL technology is a perfect fit with Orolia’s proven Resilient PNT strategy,” said Michael O’Connor, Satelles CEO. “We look forward to working together to introduce new products and solutions that will provide our customers with the utmost confidence that their positioning, navigation and timing data is accurate, secure and accessible.”

     

  • Iridium and GPS revisited: A new PNT solution on the horizon?

    Iridium and GPS revisited: A new PNT solution on the horizon?

    How many times have you heard of a nearly 20-year-old space constellation being modified with a new technology? It almost never happens.

    I will never forget when the general slid the sensitive Iridium folder across my desk; I knew from his facial expression that he was not happy. The folder contained a controversial civilian plan to de-orbit the entire multi-billion dollar Iridium communications satellite constellation less than a year after it was launched.

    Fortunately, the folder also contained a proposed military, U.S. government (USG) and joint civilian proposal to sustain the constellation, with the only caveats being that a buyer be found and that the military and/or USG provide “indemnity” (insurance policy) for the Iridium constellation if it were to be utilized by the USG and our Allies, especially during wartime. At the time I was serving as the deputy chief scientist at Air Force Space Command headquarters. Our job was to determine the technical feasibility of both proposals and make a recommendation.

    Iridium satellites

    Replica of Iridium satellite. (Photo courtesy of Iridium)
    Replica of Iridium satellite. (Photo courtesy of Iridium)

    Launched in 1998 by Motorola, Iridium is a satellite communications constellation that is a “technological marvel,” as John Bloom writes in his new book about Iridium, Eccentric Orbits. Additionally, Iridium was and remains a capability sorely needed by the USG that in many ways revolutionized global communications — unfortunately, just not in the manner or time frame Motorola originally envisioned.

    Indeed, eventually not 66 or 77, or even 88, Iridium satellites would be launched, as you will read in many places. Rather, a total of 95 Iridium satellites have been launched to date, which should give the constellation the name Americium, since 95 is the atomic number for the element americium. But I digress.

    The problem with Iridium was not technical or even space-related. Motorola, which developed the technology and launched the constellation into low Earth orbit (LEO) — an amazing feat in so many respects — totally missed the correct marketing strategy. Motorola developed Iridium as a quick (five-year lifetime) money-making capability and profit center when in fact it proved to be a much longer term project. Today, there are Iridium satellites that are fully expected to be on orbit and fully functioning for more than 20 years.

    The original Iridium satellite was — and still is — a technological marvel that broke almost all the so-called rules for manufacturing spacecraft:

    • The satellites were built without any fully space qualified or certified parts.
    • The satellites were not built in a clean room.
    • The satellites were built “horizontally” on a moving assembly line, like automobiles, versus vertically, individually and historically as a stationery static device. The moving assembly line produced a satellite every five days by a little-known company that eventually became part of Lockheed Martin (LMCO).
    • The satellites were launched by nearly every space-faring nation that had a launch capability at the time.
    • The original Iridium satellites were built for a projected lifetime of five years — that was more than 18 years ago. The current Iridium constellation of 66-plus satellites (remember, 95 have been launched) has exceeded its projected lifetime by nearly 400 percent, and is still going strong.

    In 2010, Iridium Communications entered into a long-term agreement with Boeing for maintenance, operations and support of the satellite network. Boeing operates the constellation and provides support for Iridium’s satellite control system (SCS).

    Recently, the corporation that owns Iridium announced a global space-based capability that promises to compliment GPS and other PNT constellations.

    How many times have you heard of an almost 20-year-old space constellation being modified with a new technology? It almost never happens.

    The constellation’s legacy

    Amazingly, the only reason the Iridium constellation still exists today, in several respects, is due to the intervention of the USG and a major program that suffered a production failure. Originally Motorola contracted for an additional hosted payload that just never came to fruition. The nameless company developed an Iridium test program, on which it failed to deliver. This “major glitch” caused a weight and balance problem for the Iridium satellites, which Danny Stamp, an Iridium program engineer, solved at the time by recommending a quick fix: adding an additional fuel load of the same weight as the failed payload to the satellite. It was a simple fix just to get the satellites launched on time that no one thought much about at the time. However, the result was a key component — remaining or residual fuel — that ensures the satellites are still in orbit, and can be maneuvered and working properly today.

    As I mentioned earlier, one of the major reasons the entire Iridium constellation was not de-orbited was because the USG decided it was a necessary tactical capability during wartime for our warfighters, as well as being an amazing R&R tool for morale purposes. (The Iridium system enabled conversations with loved ones back home.)

    Add to that a civilian plan put together by some true visionaries, individuals such as Dan Colussy and corporate partners such as Boeing, that were able to purchase the entire constellation for pennies on the dollar, and you have an incredible success story.

    The result is one of the most successful — certainly the largest and most well known — satellite communication constellations ever flown. Plus, as I mentioned earlier, Iridium has proposed a brand-new capability that, if it comes to fruition, has the potential be a huge boon for GPS by serving as a key global PNT augmentation.

    The way ahead

    Just last week, Iridium announced that it is proposing, or has developed, in conjunction with other companies, an augmentation or compliment to GPS. Reuters quoted the CEO of Iridium Communications, Matthew Desch as saying the new technology used chips that were the size of a postage stamp, and could ultimately be integrated into other devices, heavy machinery, automobiles and the power grid.

    The system, known as STL or Iridium Satellite Time and Location System, transmits signals via Iridium’s satellite constellation, delivering codes to ground positions that are independently authenticated, Reuters reported.

    Both Iridium and the private firm Satelles said STL as a system has been demonstrated in military, academic and commercial applications. The Reuters article didn’t provide specific details on the exact nature of the devices or any launch customers. (Satelles and Boeing entered into a patent and technology license agreement for STL in 2013).

    Iridium NEXT, Iridium’s next-generation global satellite constellation, will support the STL solution. Iridium NEXT is scheduled for completion by late 2017. Along with supporting the current Iridium constellation, Boeing is under contract from prime contractor Thales Alenia Space to provide system integration and testing support for Iridium NEXT.

    So, while STL is far from concrete, it makes for an interesting possibility that Iridium is proposing or has apparently built an on-orbit satellite augmentation to GPS, and PNT in general. My government inquires brought the to-be-expected, “We can neither confirm or deny” response. As far as Iridium and Satelles are concerned, I suppose it is a wait-and-see proposal.

    Still, it is good to see company internal R&D funding being used to further support our global PNT infrastructure. Now that the word is out, we can look for more details on the horizon. So stay tuned. By the way, many of you may remember that this is not the first time Iridium has gone down this path; perhaps this time it will actually work.

    Yes, sometimes 18 years ago seems just like yesterday.

    Note: You can read about Iridium as a GPS augmentation solution in “Iridium/GPS Carrier Phase Positioning and Fault Detection Over Wide Areas, a paper by M. Joerger, J. Neale and B. Pervan presented at ION GNSS 2009. It is available for download per ION’s current download policies.

    Abstract: The iGPS high-integrity precision navigation system combines carrier-phase ranging measurements from GPS and low-Earth orbit Iridium telecommunication satellites. Large geometry variations generated by fast moving Iridium spacecraft enable the rapid floating estimation of cycle ambiguities. Augmentation of GPS with Iridium satellites also guarantees signal redundancy, which enables fault-detection using carrier phase Receiver Autonomous Integrity Monitoring (RAIM). Over short time periods, the temporal correlation of measurement error sources can be exploited to establish reliable error models, hence relaxing requirements on differential corrections.

    In this paper, a new ionospheric error model is derived to account for Iridium satellite signals crossing large sections of the sky within short periods of time. Then, a fixed-interval positioning and cycle ambiguity estimation algorithm is introduced to process Iridium and GPS code and carrier-phase observations. A residual-based carrier phase RAIM detection algorithm is described and evaluated against single-satellite step and ramp-type faults of all magnitudes and start-times. Finally, a sensitivity analysis focused on ionosphere-related system design variables (ionospheric error model parameters, code-carrier divergence, single and dual-frequency implementations) explores the potential of iGPS to fulfill some of the most stringent navigation integrity requirements with coverage at continental scales.

    ION Joint Navigation Conference

    The highly anticipated and always rewarding Institute of Navigation Joint Navigation Conference (ION JNC) kicks off this week, June 6-9, at the Convention Center in Dayton, Ohio, and at Wright Paterson Air Force Base.

    There are the expected technical and joint presentations, along with a classified day (U.S. only) and a Warrior Panel. It all sounds like a great time and an educational experience. Be sure to visit the National Museum of the U.S. Air Force, including the website where you can take a virtual tour; it is an amazing venue. Also take time to visit the Wright Brothers exhibits in the “Birthplace of Aviation” while you are there.

    Wright Brothers 1901 Wind Tunnel on display in the Early Years Gallery at the National Museum of the United States Air Force. (Photo: U.S. Air Force)
    Wright Brothers 1901 Wind Tunnel on display in the Early Years Gallery at the National Museum of the United States Air Force. (Photo: U.S. Air Force)

    ION always puts on a great event. I hope many of you are there to participate.

    Until next time, happy navigating, and remember: GPS is brought to you free of charge, courtesy of the United States Air Force.

  • Iridium launches alternative GPS PNT service

    Iridium Communications Inc. has introduced its Satellite Time and Location (STL) service, an alternative or complement to traditional indoor and outdoor location-based technologies, and declared it ready for use. STL’s position, navigation and timing (PNT) technology is deployed through Iridium’s 66 cross-linked, low-earth orbit satellite constellation.

    Through Iridium satellites and in GNSS receivers, STL technology can work to verify GPS, GLONASS, Galileo and other navigation services, and also can serve as an alternative for those services when GPS signals are degraded or unavailable. STL also can provide an alternative source of time when testing GPS signals.

    Iridium is working with Satelles, a division of iKare Corporation, as its primary technology partner. Satelles enables Iridium’s paging channels to reach small, low-cost receivers in nearly any environment, the company says in a news release.

    “We think STL can help solve an important and growing problem for governments and businesses, and serve as a platform for continued innovation,” says Matt Desch, chief executive officer at Iridium. “With STL, we are introducing a global capability that is already in space, technologically ready for use and is independent of any particular location technology. The team at Satelles has been able to leverage the unique capabilities that our network offers to create a solution that can ultimately be integrated into almost any kind of platform, including other Iridium machine-to-machine devices, heavy machinery, automobiles and even the power grid, to name a few. Once implemented, STL could revolutionize the way the world’s largest, global companies and governments operate and manage cyber security.”

    In a chipset about the size of a postage stamp, the technology can be embedded into many devices. STL’s signal strength may make spoofing GPS systems more difficult, the company says. STL transmits its signals through Iridium’s satellite constellation to deliver a unique code to each position on the ground that can be independently authenticated, which allows operation or access only if the user is in the location expected.

    “Commercial users are now able to use STL to deliver trustworthy timing solutions for critical infrastructure, such as LTE networks, transactional data centers and the power grid,” says Greg Gutt, president and chief technology officer of Satelles. “Military and government users can also acquire these commercial off-the-shelf solutions for the Department of Defense and other government applications. In addition to enhancing the security and resiliency of GPS, STL technology can be embedded into servers anywhere in the world to geo-fence data and applications, providing trusted time and location data as an independent factor for end-point authentication.”

    The STL solution has been successfully demonstrated across multiple sectors, including military, academia and commercial applications. The technology is available today and will be supported by Iridium NEXT, the Iridium’s next-generation global satellite constellation, which is scheduled for completion by late 2017, the company says.

  • Satelles Announces Patent and Technology License Agreement with Boeing

    Satelles, a division of iKare Corporation, has entered into a patent and technology license agreement with The Boeing Company. This license allows Satelles to provide timing and location solutions to commercial markets delivered over the Iridium constellation of 66 low-Earth-orbiting satellites.

    The timing and location signals are available anywhere on Earth, without the need for local infrastructure, making the system perfect for augmenting GPS and other location-based technologies, Satelles said. Unlike standard GPS, the high-power signals can reach into many building structures. The signal-in-space provides a location-specific signature that can reliably prove (or authenticate) the location of a mobile device or other equipment, while being virtually impervious to spoofing and other attacks, Satelles said.

    Gregory Gutt, CEO of iKare Corporation, stated, “After working closely with Boeing for years to create a global indoor-positioning solution, we are thrilled to be entering this license agreement, which includes over 30 issued and pending patents.”

    Michael O’Connor, CEO of the Satelles business, agreed. “We see tremendous dual use potential for the technology going forward. Indoor location is an exciting area, and we are seeing keen commercial interest in a solution that delivers trusted location for secure network communication or network transaction security.”

    Satelles is headquartered in Silicon Valley, in Redwood City, California, with an office in Ashburn, Virginia.