GPS World

Category: GNSS

  • 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.

  • Congress yanks OCX funding; Galileo grows

    Congress yanks OCX funding; Galileo grows

    Congress Yanks OCX Funding

    SecDef Must Demonstrate Its Essential Nature

    The U.S. Senate Armed Services Committee withheld the full amount requested by the Pentagon for Fiscal Year (FY) 2017 for OCX, the Next-Generation Operational Control System (ground control) for GPS, heretofore deemed necessary to operate the next generation of satellites, GPS III. The Pentagon had asked for $394 million in the upcoming funding cycle, to enable Raytheon to continue work on the program.

    If allowed by Congress to continue, OCX may cost as much as $5.3 billion, and there is no certainty that the bill will not rise further.

    The Senate committee will not release the $394 million until the Defense Department complies with the requirements of the Nunn-McCurdy Act governing defense programs. Otherwise, Congress could act to terminate OCX.

    The terms of the Act now require the Secretary of Defense to conduct an in-depth review and then state that the program is essential to national security, is more important than other programs that will have to be cut to accommodate its cost overruns, and that there are no acceptable alternatives.

    From the Defense Department point of view, the new GPS III satellites are essential because of, among other things, their signals’ improved resistance to jamming and cyberattack, an oft-cited peril in the modern global security scenario.

    How GPS III could be launched — the first satellite is scheduled for sometime in 2017 — and operated without OCX is not entirely clear, although in February, Lockheed Martin received a $96 million contract to provide contingency control operations for the first GPS III satellites upon launch because OCX won’t be ready. Raytheon and the U.S. Air Force announced a month ago that OCX “successfully passed the first formal qualification test milestone” needed to check out the system and for the early monitoring of satellites in orbit. That “validates the maturity of the OCX launch and checkout system,” according to a statement by Bill Sullivan, Raytheon’s OCX program director.

    Raytheon won the OCX contract in 2010 with a bid somewhat more than $1.5 billion. The Air Force recently made its FY 2017 budget request for $393 million as part of an overall anticipated program cost of $4.82 billion. However, a Bloomberg news report states that the total cost may have risen to $5.3 billion.

    Galileo Launch and Production

    At press time, the latest pair of Galileo satellites was expected to launch into orbit on May 24: the 13th and 14th satellites in the constellation.

    A second launch is planned for this fall, carrying four satellites aboard a customized Ariane 5 for the first time. This would bring the count to 18 Galileo satellites in orbit by the end of the year.

    Final Payload Delivered. Surrey Satellite Technology Ltd. in the United Kingdom has delivered the 22nd Galileo navigation payload to prime contractor OHB System in Bremen, Germany. This is SSTL’s final payload under Galileo Full Operational Capability (FOC) Works Orders 1 and 2.

    Europe’s 13th and 14th Galileo satellites lifted off at 08:48 GMT from Europe’s Spaceport in French Guiana atop a Soyuz launcher. (Photo: ESA)
    Europe’s 13th and 14th Galileo satellites lifted off at 08:48 GMT from Europe’s Spaceport in French Guiana atop a Soyuz launcher. (Photo: ESA)

    BeiDou 30 over 5

    China plans to launch 30 Beidou navigation satellites during the five-year period 2016–2020, said Ran Chengqi, director of the China Satellite Navigation Office, during the China Satellite Navigation Conference in early May.

    This would realize the country’s three-step strategy to build a global navigation system by 2020. A batch of 18 satellites will be launched before 2018. China and Russia have agreed to make BeiDou and GLONASS compatible, and BeiDou has successfully synchronized its frequency with Galileo, Chengqi added.

  • GSA establishes Galileo Reference Centre to monitor performance

    News from the European GNSS Agency

    The Galileo Reference Centre (GRC), which will be established in the Netherlands, will play a crucial role in monitoring Galileo’s performance. The European GNSS Agency (GSA) made the announcement during this week’s European Space Solutions conference in The Hague.

    With Galileo Initial Services set to be declared this year, the GRC will play a pivotal role in the programme’s operations, the GSA announced during the 4th European Space Solutions conference in The Hague.

    The Galileo Reference Centre (GRC) will be established in Noordwijk, the Netherlands. The GRC’s core mission is to perform independent monitoring of Galileo’s performance and report on its findings.

    GRC’s core facility in Noordwijk will also actively integrate contributions from the EU Member States Norway and Switzerland. The core facility is charged with generating performance evaluation products, reporting and performing dedicated campaign-based analyses. It will also rely on a range of facilities and expertise available in the Member States.

    The GRC will be implemented using a versioning approach. The first step is expected to be in place at the time of declaration of Galileo Initial Services. The core facility is set to become operational in 2017.

    “The use of space data is becoming more urgent and relevant in many areas, for example in maritime safety and smart mobility,” said Melanie Schultz van Haegen, Dutch Minister of Infrastructure and the Environment. “The Galileo Reference Centre will help ensure the provision of high quality satellite data so users can better rely on and benefit from Galileo.”

    “When operational, the GRC will provide the GSA with an independent system to evaluate the performance of the Galileo Service Operator and the quality of the signals in space,” said GSA Executive Director Carlo des Dorides. Dorides and van Haegen were joined by Elżbieta Bieńkowska, European Commissioner for Internal Market, Industry, Entrepreneurship and SMEs, to officially sign the GRC hosting agreement during the conference’s opening session.

    The GRC in Brief

    • Galileo is Europe’s global navigation satellite system (GNSS), operated and maintained by the Galileo Service Operator, under contract with the European GNSS Agency (GSA).
    • The Galileo Service Operator is responsible for ensuring that the programme complies with the Galileo Services performance requirements.
    • The Galileo Reference Centre (GRC) is one of the Galileo Service Facilities: a facility to support the provision of services to the Galileo Core System and the Galileo users.
    • The GRC is operated by the GSA: it provides the GSA with an independent means of evaluating the performance of the Galileo Service Operator and the quality of the signals in space.
    • The GRC is fully independent of the system and the Galileo Service Operator with respect to both the technical solution and operations
    • The GRC is comprised of both a core facility and contributions available at EU Member States, Norway and Switzerland.
    • The core facility, located in Noordwijk (The Netherlands), is charged with:
      • generating performance evaluation products and reports using data collected by itself and through cooperation with Member States;
      • performing dedicated campaign-based analyses to support investigations of service performance and service degradations;
      • making use of the GRC’s own data, products and expertise.
    • Data and products from cooperating entities from the Member States support both daily operations and specific campaigns.
    • The GRC should benefit from but also contribute to maintaining the long term competences and expertise at the level of Member States.
    • All of the components of the GRC will be implemented using a versioning approach. The first performance monitoring solution, which primarily relies on contributions from Member States, is expected to be in place at the time of declaration of Initial Services. The core facility is expected to become operational in 2017.
  • Marconi Prize for 2016 goes to Brad Parkinson

    Marconi Prize for 2016 goes to Brad Parkinson

    Brad Parkinson
    Brad Parkinson

    The Marconi Society has awarded its 2016 Marconi Prize to Bradford Parkinson. The $100,000 prize, given annually, recognizes major advances in the field of information and communication science which benefit humanity.

    Parkinson’s contributions to the development of GPS helped create the vast global utility that provides positioning, navigation, and timing (PNT) information to the world and is a vital part of today’s global information infrastructure. The early stages of GPS were very nearly derailed and the U.S. Air Force might have abandoned its development had it not been forced to fund it. In a historic decision, the Air Force selected a project leader uniquely qualified to make it a success.

    A Bit of History. Lt. General Kenneth Schultz, Space and Missile System Office (SAMSO) Commander, called Colonel Parkinson to his office in November, 1972. The General’s purpose was to discuss a floundering USAF program called 621B, which was attempting to create a global navigation service using satellites. Parkinson wasn’t interested. “I already had a super job with a hundred million dollars of play money every year that I could spend on anything related to ballistic missile re-entry,” he recalls.  Meanwhile, the incipient GPS program was mired in technical challenges and in competition with other ideas within the Dept. of Defense.

    The General insisted. Parkinson, a rising star and perhaps the top military expert on inertial navigation, had one question. If he accepted the assignment, would he be in charge of it? When the General said, “I can’t promise that,” Parkinson said, “Then I don’t volunteer.”

    Fortunately, Schultz went ahead anyway. By the time Parkinson was ten feet out the door, the General had called personnel and initiated his transfer — in the process giving the young colonel the authority he had requested.  With sinking heart, Parkinson realized he had inherited a lot of good underlying thinking, but so much infighting that the program had ground to a halt.

    Parkinson’s career had prepared him for this project, from his study of navigation at the U.S. Naval Academy to his Master of Science study at MIT, at a time when Charles Draper was making his mark on inertial navigation, to his subsequent PhD research at Stanford University. Parkinson had taught future astronauts about satellite design and operations, and he understood navigation from the inside, as a mission commander flying combat sorties in Southeast Asia.

    An Amazing Coincidence. In what Parkinson calls “an amazing coincidence,” Dr. Mal Currie, the senior person in the Dept. of Defense for development, had just been appointed and was moving to Washington from Los Angeles. However, he needed to travel back and forth to Los Angeles for several weekends to organize his family’s move. To make it official, he would stop by the Space and Missile Systems Office for a briefing each weekend.  General Schultz soon ran out of top-level discussion topics, so someone had the bright idea to send Dr. Currie down to discuss 621B with Parkinson.

    “Here I am, a brand new colonel, given uninterrupted time with the senior-most development leader in the whole Defense Department, about five levels above me, and I have all afternoon. He is brilliant; he is a nuclear physicist. We soon got down to technical stuff. I brought out this big stack of charts and a small projector, using the wall as a screen,” Parkinson remembers. By the end of the afternoon, Parkinson had convinced Currie that GPS was a great idea. It just needed tweaking.

    With Currie’s support, Parkinson kept plugging. He requested — and got — some of the brightest minds in the Air Force to help him. He encountered opposition everywhere, even veiled threats. Finally, in August of 1973 he stood before a sea of DoD General officers and officials in Washington.  He presented GPS as it then stood, for a thumbs up or down vote. It was thumbs down. The Air Force preferred to build more planes.

    Currie, who had chaired the meeting, immediately called Parkinson to his office. “You and I know you inherited this program, but there are some improvements you can make. I’d like you to make those improvements and come right back to another decision meeting,” Currie said.

    Lonely Halls Meeting. Parkinson gathered a small group of his brightest team members. They met not in Los Angeles, where the group was based, but in the deserted Pentagon, over Labor Day weekend. The only occupants of the largest office building in the world were Parkinson’s band in a 5th floor conference room.

    They worked nonstop to change the proposal. The 621B fundamentals were sound, but several technical details had to be modulated to make it the GPS we know today. The team confirmed the use of the then-unique digital signal structure called code-division multiple-access (CDMA) that had been tested by 621B. This allowed the signals used by all the satellites to broadcast on the same frequency and insured that location precision (eventually to millimeters) could be achieved. Equally important, they decided every satellite had to carry redundant atomic clocks, so that signal timing was accurate even when on the other side of the world. Use of such clocks had been advocated by both 621B and the Navy.

    They also confirmed the over-all GPS system concept from 621B: the user would measure the range to four satellites, with knowledge of the exact time they broadcast their signal and their location, then the user could triangulate the receiver’s position as well as determine time to nanoseconds. GPS was built on this premise.

    Parkinson went back to Currie with his revised proposal in December 1973, and this time received thumbs up. Just 44 months after contract award the Air Force launched the first GPS satellite — probably a record for any military program. Today, 30 operational GPS satellites circle the planet.

    For Parkinson’s own account of these events, see The Origins of GPS, and the Pioneers Who Launched the System (Part 1), and The Origins of GPS, Fighting to Survive (Part 2).

    After retiring from military service as an Air Force colonel, Parkinson inspired a new generation of GPS scientists at Stanford, where he is a now a professor of aeronautics and astronautics, and other leading engineering schools, helping push hundreds of enhancements and new applications. At his Research Center, he and his allied faculty and students developed the concept and first demonstration of the FAA’s now-operational GPS integrity system, called WAAS.  With his students (and sponsored by John Deere) they demonstrated the first GPS auto-guided farm tractor, now an $800 million world-wide GPS farming business.  In 1992 they demonstrated the first  completely blind landing of a commercial airline (and repeated it for 110 landings!).

    “Today, there are billions of GPS receivers in the world,” says Marconi Society Vice Chairman Vint Cerf, “GPS is one of the most under-rated advances in the history of information science.  It’s taken for granted, but Parkinson was on the ground floor of enabling air, space and terrestrial guidance and navigation with GPS. His vision for the use of timing signals resulted in cellular telephone improvements, better Internet traffic control, power grid management and a myriad of important financial applications. Dr. Parkinson’s achievements have been game-changing.”

    “With immense dedication, Dr. Parkinson overcame technical and bureaucratic obstacles in order to champion the early development, and later enhancement through modernization, of GPS,” said Dr. Charles Elachi, director of the Jet Propulsion Laboratory. “We now take for granted GPS technology, whether our phone is providing turn-by-turn directions or enjoying GPS-time-synchronized communications. However, the concept of using an orbiting spacecraft’s transmitting radio signals as a solution for all-weather global navigation (positioning and timing) faced enormous obstacles during its development phase in the 1970s. As the program director for the Air Force, Dr. Parkinson and his fellow engineers were pushing the state of the art.”

    Parkinson will receive the Marconi Prize at a private ceremony at the Computer History Museum in Mountain View, CA, on November 2, 2016. He joins a select group of scientists whose work in communications and information technology has led to major advances and provided social, economic and cultural benefits for humanity. Past winners of the prize, established in 1975 by Gioia Marconi Braga, daughter of Guglielmo Marconi, have included Internet pioneers Vint Cerf, Bob Kahn and Len Kleinrock, digital trailblazers Irwin Jacobs and Henry Samueli, encryption pioneers Ron Rivest, Marty Hellman and Whit Diffie, MIMO inventor A. J. Paulraj and cell phone pioneer Marty Cooper, among others.

    GPS World is indebted to Ken Pesyna, a 2015 recipient of the Marconi Society’s Young Scholar award, for bringing this story to our attention. Pesyna co-authored the February 2015 cover story, “Accuracy in the Palm of Your Hand” and is currently CTO and co-founder at Radiosense.

    The Marconi Society was established in 1974 through an endowment set up by Gioia Marconi Braga, daughter of Guglielmo Marconi, the Nobel laureate who invented radio (wireless telegraphy). It is best known for the Marconi Prize, awarded annually to an outstanding individual/s whose scope of work and influence emulate the principle of “creativity in service to humanity” that inspired Marconi. Through symposia, conferences, forums and publications, the Marconi Society promotes awareness of major innovations in communication theory, technology and applications with particular attention to understanding how they change and benefit society.

  • GLONASS launches No. 53 to replenish constellation

    On May 29 a Soyuz-2.1b with upper stage Fregat and a GLONASS-M satellite (No. 53) successfully lifted off from Plesetsk Space Center. The satellite was placed into its preprogrammed orbit and registered by the facilities of the Titov Main Test and Space Systems Control Centre. Ground control established communications with it. The stable telemetry link shows that onboard satellite systems are functioning normally.

    According to Russian officials, an unexpected issue with the Fregat upper stage caused it to burn longer than planned to inject the satellite into its planed orbit. No further details were provided.

    The satellite is destined for a replenishment mission of the GLONASS constellation, currently at 25 operational satellites. Russian plans call for as many as eight satellites to be launched by the end of 2017 to replenish the  constellation. As part of that strategy, a Proton-M heavy carrier rocket with three GLONASS satellites aboard may take place by the end of this year.

    Below is a video of the launch.

  • TerraGo partners with high-accuracy Positioning Solutions

    TerraGo is partnering with Positioning Solutions International (PSI), a provider of high-accuracy positioning solutions for infrastructure, land management, agriculture and related industries.

    PSI is an authorized reseller of TerraGo Edge software and offers a full range of turnkey systems and services that combine mobile data-collection software from TerraGo with high-accuracy GNSS receivers from CHC Navigation.

    “What’s great about TerraGo Edge is that it’s designed to be customized out of the box, so we can give our customers and dealers a mobile solution tailored to their specific industry and unique workflow requirements,” said Charlie Towne, president, Positioning Solutions International. “And because it integrates seamlessly with the line of CHC receivers, we can provide any level of accuracy the job requires, even real-time centimeter RTK, directly on a smartphone or tablet.”

    “The PSI team has decades of experience deploying high-accuracy positioning technology to meet the most demanding customer requirements, and they understand how to help organizations use BYOD solutions to seamlessly replace legacy, proprietary technology,” said John Timar, vice president, Worldwide Sales, TerraGo. “They bring the industry experience and subject matter expertise to our projects that guarantee successful outcomes for our mutual customers using TerraGo Edge, so they can improve accuracy while realizing tremendous cost savings and improving efficiency with a modern, mobile solution.”

    PSI provides solutions to customers and a network of value-added dealers, and is the exclusive southeastern regional territory distributor for the CHC Navigation brand of GPS/GNSS products and network solutions.

  • GNSS jam-proof test range ready for customer testing

    Locatalite transceiver installation in the White Sands Missile Range Ultra High-Accuracy Reference System, provided by the U.S. Air Force for testing equipment under conditions of GPS jamming.
    Locatalite transceiver installation in the White Sands Missile Range Ultra High-Accuracy Reference System, provided by the U.S. Air Force for testing equipment under conditions of GPS jamming.

    A new dimension in real-world PNT testing has arrived. One of the most critical things to predict for chips, receivers and devices using alternative or back-up PNT technologies is how they will actually perform without GPS.

    Filling this need, the U.S. Air Force 746th Test Squadron has declared Initial Operational Capability (IOC) for its new truth reference, the Ultra High-Accuracy Reference System (UHARS) at the White Sands Missile Range in New Mexico. Even when GPS — or any other GNSS system — is being completely jammed, UHARS provides extremely accurate positioning, navigation and time (PNT) over the large area that the system was designed to cover.

    “Initial testing shows that UHARS delivers accurate independent PNT as good as, or better than, the Air Force’s current Central Inertial and GPS Test Facility (CIGTF) Reference System (CRS), so it is perfectly able to support current customer requirements,” said Dr. Jim Brewer, Chief Scientist of the 746th Test Squadron. “However, more data are required to tune the UHARS filter and optimize its accuracy to meet even tighter PNT requirements, which is our objective. When this is achieved, UHARS will deliver truth accuracy for next-generation military capabilities, and we will declare UHARS Full Operational Capability.”

    “UHARS is a rack-mounted, tightly integrated system of improved navigation sensors, a data acquisition system (DAS) and a new post-mission Kalman filter, all of which need to work together,” explained John Cao, Technical Director of the 746th Test Squadron. “It’s working very well, but once we completely measure and characterize the individual components and then tune and validate the filter, the complete system will provide a significantly more accurate reference solution for future airborne and land-based test vehicles in navigation warfare environments where modernized and legacy GPS signals are jammed from friendly or hostile systems.”

    To achieve these accurate reference solutions, UHARS requires a core Non-GPS Based Positioning System (NGBPS) component capable of operating and providing sub-meter position accuracy in a GPS-denied (jamming) environment. The NGBPS subsystem of the UHARS program employs a network of ground-based LocataLite transceivers and test vehicle receivers manufactured by the Locata Corporation. The Locata network deliver centimeter-level positioning and navigation as well as nanosecond-level synchronization, which may be useful for military applications requiring precise time transfer in GPS-denied environments.

    White Sands Missile Range (WSMR) is a United States Army rocket range of almost 3,200 sq mi (8,300 sq km) in parts of five counties in southern New Mexico. It is the largest military installation in the United States.

    The importance and uniqueness of the WSMR as GPS test facility spring from the fact that it is illegal to jam GPS elsewhere without a special permit. Thus it is extremely difficult to create a real-world test scenario for various GPS and other PNT devices, to see how they perform under denied or restricted circumstances. This is of critical importance for flight testing (UAVs and other avionics) for which the UHARS was primarily designed and optimized.

    The LocataNet truth reference system can also provide a 2D solution to support ground vehicle testing.  Reportedly, the 2D solution, while also very good, has not yet been fully characterized. Once the filter has been fully tuned in this respect, WSMR could serve as a test facility for autonomous driving. There are many miles of paved highway on the WSMR, possibly in the hundreds of miles.

    History of UHARS Development. Based on successful results of the original technical demonstration at WSMR in a real-world end-to-end environment, the USAF proceeded to the NGBPS production and fielding phase in 2012. The Locata Corporation was contracted to provide production ground transceivers and receivers, navigation algorithms required for data analysis and subject matter expertise. The TMC Design Corporation, the integrating contractor for this program, was tasked to develop the production hardware to house the Locata hardware, develop the command and control hardware and software, and field the production hardware at WSMR. The Locata network was fielded in September 2014, and its NGBPS capability is now core to the UHARS that is replacing the CRS.

    “Our team is thrilled to be part of this historic USAF capability,” said Nunzio Gambale, CEO and co-founder of Locata Corporation. “Locata products developed and fielded by important commercial partners like Hexagon and Perrone Robotics routinely prove our technology is a game-changer for positioning over industrial-sized areas. However, leveraging Locata technology as the core non-GPS-based PNT solution over a vast military area when GPS is jammed instantly elevates our achievements into a completely new league. Clearly, we are witnessing the arrival of one of the most important technology developments for the future of the entire PNT industry.”

    Customers wishing to leverage UHARS into their test programs should contact the 746th Test Squadron at (575) 679-2123 or [email protected] for scheduling information.

  • Air Force jam-proof reference system ready to support testing

    The U.S. Air Force 746th Test Squadron has declared Initial Operational Capability (IOC) for its new truth reference, the Ultra High-Accuracy Reference System (UHARS), which employs LocataLite transceivers.

    Even when GPS is being completely jammed, UHARS provides extremely accurate positioning, navigation and time (PNT) over the large area of White Sands Missile Range (WSMR) in New Mexico that the system was designed to cover.

    To achieve these accurate reference solutions, UHARS requires a core Non-GPS Based Positioning System (NGBPS) component capable of operating and providing sub-meter position accuracy in a GPS-denied (jamming) environment. The NGBPS subsystem of the UHARS program employs a network of ground-based LocataLite transceivers and test vehicle receivers manufactured by the Locata Corporation.

    Further details on the White Sands UHARS appear in the GNSS Design & Test e-newsletter from GPS World. For a free subscription, visit env-gpsworld-integration.kinsta.cloud/subscribe.

  • 14 Galileo satellites now in orbit

    14 Galileo satellites now in orbit

    The Galileo satellite navigation system that will help Europe find its way in the 21st century now has 14 satellites in orbit after today’s double launch.

    Galileos 13 and 14 lifted off together at 08:48 GMT (10:48 CEST, 05:48 local time) atop a Soyuz rocket from French Guiana.

    This seventh Galileo launch went by the book: the first three Soyuz stages placed the satellites safely into low orbit, after which their Fregat upper stage hauled them the rest of the way into their target medium-altitude orbit.

    The twin Galileos were deployed into orbit close to 23,522 km altitude, inclined 57.394 degrees to the equator, 3 hours and 48 minutes after liftoff. The coming days will see a careful sequence of orbital fine-tuning to bring them to their final working orbit, followed by a testing phase so that they can join the working constellation later this year.

    Europe’s 13th and 14th Galileo satellites lifted off at 08:48 GMT from Europe’s Spaceport in French Guiana atop a Soyuz launcher. (Photo: ESA)
    Europe’s 13th and 14th Galileo satellites lifted off at 08:48 GMT from Europe’s Spaceport in French Guiana atop a Soyuz launcher. (Photo: ESA)

    “Today’s textbook launch has added two more satellites to what has become Europe’s largest satellite constellation,” commented Jan Woerner, director general of ESA. “It was made possible by the fact that European industry’s manufacturing and testing of Galileo satellites has achieved a steady tempo.”

    “Today’s launch brings Europe’s Galileo constellation halfway to completion, in terms of numbers,” remarked Paul Verhoef, ESA’s Director of the Galileo Programme and Navigation-related Activities.

    “It is also significant as Galileo’s last flight by Soyuz this year before the first launch using a customised Ariane 5 to carry four rather than two satellites each time – which is set to occur this autumn.

    “Meanwhile, hard work is proceeding behind the scenes to ensure the worldwide Galileo system, including its far-flung ground stations, is reliable, secure and robust for the start of operational services to users.”

    Full video replay of the launch is available here.

    The launch was carried out from the purpose-built ELS launch complex at Europe’s Spaceport,. Total payload lift performance was estimated at 1,599 kg.

    The flight had an early morning liftoff from the Spaceport – coming at precisely 5:48:43 a.m. French Guiana time. This Arianespace Soyuz mission was performed at the service of the European Commission, which is managing the Galileo program’s ongoing FOC (Full Operational Capability) phase. Design and procurement agent responsibilities have been delegated to the European Space Agency (ESA) on the commission’s behalf.

    It is during the FOC phase that the Galileo network’s complete operational and ground infrastructure will be deployed. Today’s Soyuz mission — designated Flight VS15 — was Arianespace’s fifth overall carrying FOC spacecraft in sets of two. It follows one launch in 2014 (VS09), then three performed last year (VS11, VS12 and VS13). The medium-lift workhorse also lofted a total of four satellites in the program’s IOV (in-orbit validation) phase in 2011 and 2012.

    The satellites orbited today — named “Danielė” and “Alizée” after winners of a European Commission-organized painting competition for children — are the 13th and 14th Galileo spacecraft overall to be orbited by Arianespace.

    The spacecraft’s onboard payloads were supplied by UK-based Surrey Satellite Technology Limited (SSTL) — a company 99-percent owned by Airbus Defence and Space, which is an Arianespace shareholder, as well.

    Israël acknowledged others that contributed to this latest Arianespace success, including State Space Corporation Roscomos and Russia’s industrial partners involved in the production and operation of Soyuz; along with the European support companies; the French CNES space agency; the ground contractors in French Guiana and Arianespace’s own teams.

    Arianespace will conduct another launch for Galileo’s FOC phase later in 2016 — this time using an Ariane 5 and its heavy-lift capability to orbit a four-satellite payload. Two additional launches of the heavy-lift workhorse in 2017-2018 will bring total Galileo deployments to 26 spacecraft.

  • 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.

  • Galileo 13 and 14 satellites ready for Tuesday launch

    Galileo 13 and 14 satellites ready for Tuesday launch

    Galileos 13 and 14 are scheduled to lift off at 08:48:43 GMT (05:48:43 local time, 10:48:43 CEST) on May 24 from Europe’s Spaceport in French Guiana atop a Soyuz launcher.

    The first three stages of the Soyuz rocket take the Galileo satellites and their Fregat upper stage into low orbit nine minutes after liftoff. Then the reignitable Fregat, as much a spacecraft as a rocket stage, takes over the task of hauling the satellites higher through a pair of burns.

    The satellites will be released in opposite directions by their dispenser once they reach their target 22,522-kilometer-altitude orbit 3 hours and 48 minutes after launch.

    On Wednesday, May 18, Europe’s latest Galileo satellites were placed atop their upper stage then enclosed within their protective rocket fairing. The encapsulation took place inside the Spaceport’s cleanroom, as a two-piece Soyuz fairing was closed around the satellites, attached to their carrier atop the Fregat upper stage.

    Europe's 13th and 14th Galileo satellites being encapsulated inside their launcher fairing. (Photo: ESA)
    Europe’s 13th and 14th Galileo satellites being encapsulated inside their launcher fairing. (Photo: ESA)

    The satellites had been installed on Fregat the previous day. This versatile upper stage will haul them the bulk of the way to their target 23,500-kilometer-altitude orbit.

    The sealed satellites, dispenser and upper stage are collectively known as the “upper composite.” Today, the plan is to roll out the first three stages of Galileo’s Soyuz to the launchpad, ready for mating with this upper composite.

    This will be the seventh Galileo launch, set to bring the number of satellites in space up to 14. Four more Galileos are planned to take flight in the autumn, launched for the first time on a customized Ariane 5 to bring the total number of satellites in the constellation to 18.

    Watch the launch live here. Streaming begins at 08:28 GMT (10:28 CEST) on 24  May for the liftoff, then resumes at 12:23 GMT (14:23 CEST) to cover the satellites’ separation.

    For other upcoming GNSS satellite launches, see this page.

    Early Operations Phase. According to the European Space Agency (ESA), a combined team of specialists is conducting final training at ESA’s ESOC mission control centre to prepare for the launch.

    The team comprises over 40 experts drawn from ESA and from France’s CNES space agency, supported by additional specialists at both agencies in areas such as flight dynamics and ground stations.

    Within the combined flight control team, each position is paired with its counterpart from the other agency and mixed CNESOC shifts will rotate to conduct operations around the clock.

    The same team conducts all the Galileo early operations alternately from ESOC and from the CNES control centre in Toulouse, France.

    By launch day, the teams will have completed a demanding series of joint simulation training sessions at ESOC, complemented by more specific training conducted separately at each control centre. Joint sessions are especially important to develop team bonds “on-console” — so individuals get to know who will be working beside them and can foster one-on-one teamwork and mutual support.

    Three Flight Operations Directors and three Spacecraft Operations Managers will work together with their teams in each of three shifts during the nine-day early operations phase. From left: Hélène Cottet (CNES), Remi Lapeyre (CNES), Liviu Stefanov (ESA), Christelle Crozat (ESA), Thomas Cowell (ESA) and Hervé Côme (ESA).
    Three Flight Operations Directors and three Spacecraft Operations Managers will work together with their teams in each of three shifts during the nine-day early operations phase. From left: Hélène Cottet (CNES), Remi Lapeyre (CNES), Liviu Stefanov (ESA), Christelle Crozat (ESA), Thomas Cowell (ESA) and Hervé Côme (ESA).

     

  • NovAtel: Proposed Ligado wireless network a concern for high-precision positioning

    NovAtel Inc. has submitted comments to the Federal Communications Commission (FCC) regarding Ligado Networks LLC’s (formerly New LightSquared LLC) License Modification Applications. NovAtel raises deep concerns about the testing methodology used and conclusions presented by Ligado regarding the impact of its proposed usage of L-band frequencies for a terrestrial wireless network.

    In its filing, NovAtel identified serious flaws in the testing methodology used to evaluate high precision receivers. Although high-precision receivers were used during the testing, the high-precision position modes that are used to achieve centimeter-level positioning accuracy required by many professional and safety-critical applications were not evaluated. The study shows a lack of understanding of the uses of the GPS by assuming that all applications require the same positioning accuracy, NovAtel said.

    The filing also raises a number of concerns about the potential harmful interference impact on GPS receiver performance. NovAtel is particularly concerned that Ligado has moved away from what it understood to be an agreed upon standard that interference tolerance should be limited to a received interference signal power level that causes no more than 1-dB degradation in the received C/No level. NovAtel disagrees with the conclusion in the RAA Study that there is no meaningful correlation between a 1-dB change and GPS performance. NovAtel submits any interference must not exceed 1-dB degradation in received C/No if robust, precise positioning is to be maintained. Ligado has not yet proven that its use of the spectrum will not be detrimental to high-precision users of the Global Navigation Satellite System (GNSS), which is what the 1-dB C/No degradation metric ensures.

    “To date, Ligado has not proven that its use of the proposed spectrum can be made compatible with high-precision GNSS,” NovAtel said in a press release. “The interference impact on the other GNSS constellations such as Galileo, GLONASS and Beidou has not been addressed. These constellations are increasingly used in combination with GPS for many high-precision applications. Proposed, unverified mitigation methods such as narrowband antennas are presented in the Ligado filing without explanation of who will be responsible for the cost of such design modifications and retrofit programs.”

    To view NovAtel’s FCC filing in its entirety, visit the FCC website.