GPS World

Tag: PNT Roundup

  • Canada, US workshops focus on PNT threats

    Canada, US workshops focus on PNT threats

    Two workshops convened in recent weeks in the U.S. and Canadian capitals, respectively, sought to bring into focus looming threats to the nations’ positioning, navigation and timing capabilities and critical infrastructures. Some of the threats are pervasive — jamming and spoofing — and formed the general topic of the Canadian workshop. Some threats are specific — powerful terrestrial transmitters overwhelming GPS/GNSS receivers — and occasioned the U.S. gathering.

    Canada. In a first for Canada, the October 21 GNSS Vulnerabilities Innovation Policy (VIP) Workshop brought together 19 federal government departments as well as  provincial and municipal agencies and private sector companies.  U.S. State Dept. and Homeland Security gave presentations, as did the European Space Agency, Bell Canada, NovAtel and Spirent Communications.

    Integrity challenge for automotive positioning, presented by NovAtel
    Integrity challenge for automotive positioning, presented by NovAtel

    The workshop was sponsored by the the Federal Global Navigation Satellite Systems Coordination Board (FGCB), a government board with representations from various government departments and agencies. The GNSS Coordination Office (which organized the workshop) is hosted at Canada’s Ministry of Innovation, Science and Economic Development and sponsored by the FGCB members.

    Presentations covered such topics as Demonstration of the Geolocation of GPS Jammers, GNSS & the Telecom Sector, Detecting and Protecting Against GPS Cyberthreats, and Safety Critical, High Precision, GNSS Positioning for Autonomous Vehicles.

    United States. The U.S. Department of Transportation (DOT) hosted its fifth workshop on the GPS Adjacent-Band Compatibility Assessment effort on October 14. This lengthy, thorny and occasionally acrimonious process started out benignly enough in 2010 with the statement, “Demand for commercial spectrum to support broadband wireless communications has led the government to consider repurposing various radio frequencies, including the satellite communications bands next to GPS.”

    The workshop discussed the results from testing of various categories of GPS/GNSS receivers including aviation (non-certified), cellular, general location/navigation, high precision and networks, timing, and space-based receivers. The workshop also included a discussion on the development of use-case scenarios for these categories — which is where the going got heavy and differences of opinion truly emerged.

    DOT has posted all presentations from the workshop.  Scroll down to “October 2016 Workshop.”

    The furor stems from a renewed effort by Ligado, formerly known as LightSquared and now re-emergent from a 2-year bankruptcy process, to convert relatively inexpensive satellite-to-earth spectrum into very valuable terrestrial spectrum. The company stands to gain billions of dollars and secured rights from the process.

    Members of the DoT team presented the first results from the GPS Adjacent-Band Compatibility (ABC) Assessment, an effort to determine the power limits by frequency, or interference tolerance masks (ITM), needed to protect both existing and future GPS receivers. Test results indicated a need to limit interfering signals at different levels depending on the type of receiver being used. 80 receivers in six categories were tested: cellular, general location/navigation, general aviation, timing, high precision and space receivers. Certified and military receivers are undergoing separate tests.

    The tests of current receivers took place April 25–29 at White Sands Missile Range, New Mexico, using a 100 x 70 x 40 anechoic chamber. The signals used in the test included GPS L1 C/A-code, GPS L1 P-code, GPS L1C, GPS L1 M-code, GPS L2 P-code, SBAS L1, GLONASS L1 C, GLONASS L1 P, BeiDou B1I and Galileo E1 B/C. Tests were conducted within 100 megahertz on either side of the GPS L1 center frequency of 1575.42 using a 10-megahertz LTE signal and a narrow bandwidth 1-megahertz bandpass white noise signal.

    The tests were conducted for GPS and GNSS receivers processing signals in the 1559–1610 MHz Radionavigation Satellite Service (RNSS) frequency band, as well as receivers that process Mobile Satellite Service (MSS) signals in the 1525–1559 MHz band to receive differential GNSS corrections.

    The tests determined the power levels at which each device experienced a one-decibel degradation in the carrier-to-noise density ratio (CNR) at a particular frequency. The DoT team graphed results for each device. The recommended power limits were the lowest in frequencies closest to the GPS bands.

    The receivers most affected by the test transmissions were identified as high-precision receivers. They experienced interference at power levels as low as –90 to –95dBm at around 1550 MHz and –90 dBm at roughly 1610 MHz.

    highprecision-gps-l1-receiver-category

    The strictest limit for both the general aviation, general navigation/location, and timing receivers was a little below –80 dBm at about 1550 MHz, while space-based receivers were equally sensitive on both sides of the RNSS band with the toughest limit being about –85 dBm.

    FAA. The Federal Aviation Administration (FAA) has authority to set power and out-of-band emissions limits to meet aviation safety standards, and it had been thought that these limits might  address interference with other types of receivers as well. But the test results showed that “protecting the FAA-certified mask does not necessarily protect the rest of the receiver categories,” according to Hadi Wassaf, technical lead for GPS interference analysis at DoT’s Volpe Center.

    Use Cases. Ligado has proposed that position error as experienced by the user is a better guide to interference levels than degradation in the carrier-to-noise density ratio. The GPS community generally opposes this approach. The next step is the development of use cases. According to the test plan, use cases define the regions of operations for a receiver, and they identify applications that “that are vital to economic, public safety, scientific, and/or national security needs and any other factors supporting why this particular receiver model is important to be tested (e.g., quantity in use, economic impact, etc.).”

  • DARPA floats aerial surveillance Dragnet by UAV

    DARPA floats aerial surveillance Dragnet by UAV

    As off-the-shelf unmanned autonomous systems (UAS) become less expensive, easier to fly, and more adaptable for terrorist or military purposes, U.S. forces will increasingly be challenged by the need to quickly detect and identify such craft, especially in urban areas, where sight lines are limited and many objects may be moving at similar speeds.

    To map small UAS in urban terrain, the U.S. Defense Advanced Research Projects Agency (DARPA) seeks innovative technologies to provide persistent, wide-area surveillance of all UAS operating below 1,000 feet in a large city. While the newAerial Dragnet program focuses on protecting military troops operating in urban settings overseas, the system could ultimately find civilian application to help protect U.S. metropolitan areas from UAS-enabled terrorist threats.

    “Commercial websites currently exist that display in real time the tracks of relatively high and fast aircraft—from small general aviation planes to large airliners—all overlaid on geographical maps as they fly around the country and the world,” said Jeff Krolik, DARPA program manager. “We want a similar capability for identifying and tracking slower, low-flying unmanned aerial systems, particularly in urban environments.”

    Although several systems are being developed for tracking small UAS by extending surveillance methods used in open areas where large line-of-sight buffers mitigate the threat, these systems are impractical for operation in urban terrain. Aerial Dragnet seeks to leapfrog these approaches by developing systems adapted to the fundamental physics of small UAS in urban environments that could enable non-line-of-sight (NLOS) tracking and identification of a wide range of slow, low-flying threats.

    The program envisions a network of surveillance nodes, each providing coverage of a neighborhood-sized urban area, perhaps mounted on tethered or long-endurance UAS. Using sensor technologies that can look over and between buildings, the surveillance nodes would maintain UAS tracks even when the craft disappear from sight around corners or behind objects.

    Low Cost Sensors, SDR. The output of the Aerial Dragnet would be a continually updated common operational picture of the airspace at altitudes below where current aircraft surveillance systems can monitor, disseminated electronically to authorized users via secure data links. Because of the large market for inexpensive small UAS, the program will focus on combining low-cost sensor hardware with software-defined signal processing hosted on existing UAS platforms. The resulting surveillance systems would thus be cost-effectively scalable for larger coverage areas and rapidly upgradeable as new, more capable and economical versions of component technologies become available.

    The Aerial Dragnet program seeks teams with expertise in sensors, signal processing, and networked autonomy to achieve its goal. A solicitation detailing the goals and technical details of the program was posted here. A Proposers Day took place in late September.

    Inertial, Gyroscope Take to Space

     

    The concept image above shows the NEA Scout CubeSat with its solar sail deployed as it characterizes a near-Earth asteroid. (NASA)

    Sensonor AS of Norway has partnered with the U.S. National Aeronautics and Space Administration (NASA) to supply current and future low- and near-Earth orbit space missions with inertial and gyroscope modules.

    The Norway-based company first began supplying its standard inertial measurement unit (IMU) and gyroscope modules for low Earth orbit (LEO) space applications in 2012, Sensonor’s STIM300 and STIM210 inertial products now fly aboard several NASA spacecraft. Current projects using STIM inertial systems include the Raven technology demonstration and Near Earth Asteroid (NEA) Scout.

    Raven, which launched to the International Space Station in September, will test key elements of an autonomous relative navigation system. Its technologies may one day help future robotic spacecraft autonomously and seamlessly rendezvous with other objects in motion, such as a satellite in need of fuel or a tumbling asteroid.

    The NEA Scout is a robotic reconnaissance mission that will be deployed to fly by and return data from an asteroid representative of NEAs.

    The STIM gyroscope modules are often used in combination with GPS or a Star Tracker and Kalman filter to orient and stabilize the satellite, as well as to provide feedback on satellite motion induced by its reaction wheels. In some applications, the gyroscopes are used to stabilize satellite-to-satellite communications.

    Lighting Up Indoors for Retail Position

    A new indoor positioning system uses LED lighting to pinpoint location for use in the retail industry. Researchers from the University of South Australia have developed an indoor positioning system that tracks movement with greater accuracy than contemporary RFID and Wi-Fi based systems.

    Developer Siu Wai Ho said other methods of indoor positioning such as Wi-Fi were only accurate to within 1–2 metres and were easily hampered by radio frequencies from nearby devices, power sources or other wireless electronics. “Our system is more accurate with an error margin of 10cm and unlike some positioning systems our algorithm can calculate the orientation at the same time.”

    LiPo uses LED lights as transmitters and photodetectors as receivers because they are both common items in modern societies. Photodetectors are a key component for capturing light and are also commonly found in smart phone cameras. The system uses a specially designed receiver to measure light intensity that is able to calculate position and orientation. Although it currently requires a unique receiver, developers hope to integrate the technology with the photodectors in mobile phones. This would reportedly enable supermarkets to provide customers with relevant information about items nearby.

    “If you are in a supermarket you want to see some information for a product in front of you. One or two metres of error is still too big because it maybe gives you a product you are not in front of.”
    Other applications could include the identification of objects or machinery in factories, movement aid tools for the elderly and trackers for museums to provide relevant information to tourists as they passed by exhibits.

    Munich SatNav Summit Stresses GNSS Back-Up

    “Is it Time for GNSS Back-Up?” has been announced as the the theme of the 2017 Munich Satellite Navigation Summit, to take place March 14–16.International experts gather to discuss recent position, navigation and timing develeopment and the necessity for GNSS backup solutions.

    Among the topics, in addition to system updates on all major GNSS, we find listed: From Iridium to e-Loran — GNSS in need for a Backup; Galileo after the Brexit; Civil use of the Galileo Public Regulated Service (PRS); and Network-based solutions for GNSS Backup. Go to to www.munich-satellite-navigation-summit.org for registration information.

    Xsens Offers Knowledge BASEd Inertial Motion Tracking

    Xsens has launched BASE, an online technology platform with a community forum and a knowledge base on 3D motion tracking technology and products. BASE.xsens.com, contains inside information about micro-electro-mechanical system (MEMS) sensors, inertial measurement units (IMU), sensor fusion algorithms, body-motion tracking and motion capture.

    It also provides best practices, tips and tricks for the use of Xsens’ MTi series, the MTw and the MVN wearable motion capture solutions. A second section of BASE is the community forum with direct access to Xsens’ engineers and other Xsens users.

    There is no need to register for BASE to access the community forum and the knowledge base. To ask questions or comment on articles, registration is possible via SSO or email.

  • PNT Roundup: DARPA FLA program tests sensor-loaded quadcopters

    DARPA-FLA-drone

    MicroUAVs Self-Navigate Indoors with Inertial, Cameras, More

    The sensor-loaded quadcopters edged around obstacles and achieved target speeds of 20 meters per second in a cluttered Massachusetss hangar, during initial data collection for the U.S. Defense Advanced Research Projects Agency (DARPA) Fast Lightweight Autonomy (FLA) program.

    The project develops and tests algorithms to reduce the amount of processing power, communications and human intervention needed for UAVs to accomplish low-level tasks.

    If successful, FLA would reduce operator workload and stress and allow humans to focus on higher level supervision of multiple formations of manned and unmanned platforms as part of a single system.

    Military teams patrolling dangerous overseas urban environments and rescue teams responding to disasters such as earthquakes or floods currently can use remotely piloted unmanned aerial vehicles (UAVs) to provide a bird’s-eye view of the situation.

    But to know what’s going on inside an unstable building or a threatening indoor space often requires physical entry, which can put troops or civilian response teams in danger.

    FLA technologies could be especially useful to address this pressing surveillance shortfall by furnishing operatives independent of communication with outside pilots or sensors and without reliance on GPS.

    PNT Payload

    The platform tested by DARPA researchers uses a commercial DJI Flamewheel 450 airframe, E600 motors with 12-inch propellers, and 3DR Pixhawk autopilot. It carries high-definition onboard cameras and other sensors, such as lidar, sonar and inertial measurement units.

    The tests demonstrated autonomous capabilities such as seeing obstacles and flying around them at slow speed unaided by a human controller.

    The three performer teams are Draper teamed with the Massachusetts Institute of Technology; the University of Pennsylvania; and Scientific Systems Company teamed with AeroVironment. Flights and data collection took place at Otis Air National Guard Base in Cape Cod, Massachusetts, with simulated walls, boxes and obstacles to test agility and speed.

    The tests did produce several crashes. “The only way to achieve hard goals is to push physical systems and software to the limit,” said program manager Mark Micire. Continuing tests will obstruct the venue with more obstacles and clutter. “What makes the FLA program so challenging is finding the sweet spot of a small size, weight and power air vehicle with limited onboard computing power to perform a complex mission completely autonomously.”

  • PNT Roundup: Remote and autonomous ships coming to high seas

    PNT Roundup: Remote and autonomous ships coming to high seas

    Remote and Autonomous Ships

    Coming Soon to the High Seas Near You

    Image courtesy of Rolls-Royce.

    The Advanced Autonomous Waterborne Applications Initiative (AAWA) published a white paper in June as part of presentations at the Autonomous Ship Technology Symposium 2016 in Amsterdam. The white paper outlines the Project’s vision of how remote and autonomous shipping will become a reality.

    Oskar Levander, Rolls-Royce vice president of Innovation – Marine, said, “This is happening. It’s not if, it’s when. The technologies needed to make remote and autonomous ships a reality exist. The AAWA project is testing sensor arrays in a range of operating and climatic conditions in Finland and has created a simulated autonomous ship control system which allows the behaviour of the complete communication system to be explored. We will see a remote controlled ship in commercial use by the end of the decade.”

    The AAWA white paper explores the research carried out to date on the business case for autonomous applications, the safety and security implications of designing and operating remotely operated ships, the legal and regulatory dimensions and the existence and readiness of a supplier network to deliver commercially applicable products in the short to medium term.

    Positioning Technologies. The proposed system draws on a range of sensors (see Figure 1) including GPS, inertial, lidar, cameras, short-range radars, and electronic charts. “When combined witha global or local positioning reference such as GNSS, and with wind sensors and inertial measurement units, the ship is able to keep its position even in rough weather conditions,” states the report. “The main question is therefore not whether the implementation of autonomous ship navigation is technically possible, but what is the combination of technologies and methods that provides the level of performance and reliability that is required for practical operation of large vessels, and at a reasonable cost.”

    The white paper draws on a wide range of expertise from academic researchers at some of Finland’s leading universities. Industry input has been provided by leading members of the maritime cluster including Rolls-Royce, Brighthouse NAPA, Deltamarin, DNV GL and Inmarsat.

    The project also has the support of shipowners and operators. The tests of sensor arrays are being carried out aboard Finferries 65-metrer double ended ferry, the Stella, which operates between Korpo and Houtskär. ESL Shipping Ltd is helping explore the implications of remote and autonomous ships for the short sea cargo sector.

    Iran Reiterates Loran Effort

    Researchers at Iran’s Malek-Ashtar University have developed a 1-megawatt transmitter with half-cycle technology for a national project announced as a replacement for GPS, which is currently employed for all positioning, navigation and timing services across the country. Given the lack of control on the GPS’s accuracy and quality and a possible outage of the system in critical conditions, the country’s defense ministry has set out to develop a local positioning system (LPS) for positioning and timing.

    Experts at the U.S.-based Resilient PNT Foundation say the description of the system make it appear to be a variant of Loran, probably similar to those operated in Russia and China. If it is such a Loran variant and if it complies with international standards, it should complement Saudi Arabia’s Loran signals in the Persian Gulf, they said.

    Iran will establish five stations with powerful transmitters in appropriate locations to provide navigation, positioning and timing services in compliance with international standards, according to the country’s defense minister.

    Iran made a similar announcement about a land-based navigation system in December 2013. The country’s military experts and technicians have reportedly logged significant progress in manufacturing a broad range of indigenous equipment.

    U.S. eLoran August demonstration

    The Wildwood, New Jersey, eLoran transmitter will continuously broadcast from July 29 through 12 p.m. Eastern time on Aug.15. Wildwood will broadcast as 8970 Master and Secondary most of the time but occasionally may operate at other rates.

  • 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.

  • PNT Roundup: Self-driving cars need FOG, inertial

    New products come to market poised for take-off

    KVH high-precision fiber-optic gyro. The red illumination in the photo represents light moving through the FOG’s optical circuit of coiled fiber. This circuit is the FOG’s sensing unit, mounted with power and processing electronics within a driverless car to provide precise data for the car’s navigation systems.
    KVH high-precision fiber-optic gyro
    The red illumination in the photo represents light moving through the FOG’s optical circuit of coiled fiber. This circuit is the FOG’s sensing unit, mounted with power and processing electronics within a driverless car to provide precise data for the car’s navigation systems.

    Fiber-optic gyros (FOGs) and FOG-based inertial measurement units (IMUs) form key parts of the integrated sensor systems essential for highly accurate autonomous car performance. For example, FOGs provide precise azimuth measurements that an autonomous car’s logic processing unit and control systems need to determine motion through a curve.

    An IMU — which can include FOGs and accelerometers in one compact package — also provides highly accurate six-degrees-of-freedom angular rate and acceleration data to precisely track the position and orientation of the car even when GPS is unavailable, helping the car stay on course.

    KVH Industries is developing a FOG-based, low-cost inertial sensor for self-driving cars. The company has also released a Developer’s Kit to assist design engineers with integrating FOG technology into driverless car control systems.

    “Extremely precise heading based on fiber-optic gyro technology is absolutely essential for autonomous vehicle performance,” said Martin Kits van Heyningen, KVH’s chief executive officer. “This is something we learned from having been involved with more than a dozen driverless car development programs over the years.”

    “What we are seeing now is that each driverless vehicle concept in development around the world is being designed in a unique way,” van Heyningen continued. “With so many different possibilities, developers can accelerate their progress by working with a proven technology such as KVH’s FOGs and FOG-based IMUs and leveraging our experience to ensure their success.”

    Developer’s Kit

    The new Developer’s Kit includes the user interface software and all components needed to connect a KVH FOG or FOG-based IMU to a computer to configure, analyze and test a unit. “The kit is designed to help engineers get up and running in minutes, making it easier to run diagnostics and accelerate their system development,” said Roger Ward, KVH’s director of FOG product development.

    “We have successfully produced more than 90,000 fiber-optic gyros for an extensive range of unmanned applications, in part because of our ability to tailor size, performance and cost to meet different design needs,” said Jeff Brunner, KVH’s vice president for FOG operations. “Controlling the entire FOG design and manufacturing process gives us that advantage, and makes it possible to produce a low-cost sensor when driverless cars enter full-scale production.”

    KVH’s FOGs and FOG-based IMUs are in use in prototype programs not only for autonomous cars, but also for production programs for underwater unmanned vehicle navigation and rail/track geometry measurement systems, to name just a few. In addition, KVH’s inertial products have been widely adopted for commercial applications such as land-based street-mapping platforms, unmanned aerial systems, camera-stabilization systems and remotely operated subsea systems.

    KVH’s 1750 IMU was an integral part of 11 of the 23 humanoid robot finalists in last year’s DARPA Robotics finals, a competition designed to showcase robots capable of intervening for and even replacing humans in high-risk situations such as fires, earthquakes and other natural disasters.

  • South Korea to build eLoran system after jamming incident

    South Korea will award a contract this month to secure technology required to build an eLoran system as an alternative to GPS, reports the Australian Broadcasting Company (ABC).

    The announcement follows South Korea pointing the finger at North Korea for jamming its GPS signal reception in late March.

    The South Korean eLoran plan envisions setting up coastal transmitters by the end of 2019, said Seo Ji-won, a government advisory panel member and professor at Yonsei University.

    “The need for us is especially high, because of the deliberate signal interference by North Korea,” a South Korean government official told Reuters, as reported by ABC.

    The latest jamming campaign from the North began on March 31. According to ABC, the jamming lasted nearly a week and affected signal reception of more than 1,000 aircraft and 700 ships, with the jamming originating from five locations along the border, South Korean officials said.

    GPS vulnerability poses security and commercial risks, especially for ships whose crews are not familiar with traditional navigation techniques or using paper charts. Vessels such as fishing boats lack backup electronic navigation systems.

    Air traffic was not usually affected because the GPS system is normally used as a backup in South Korea, not a primary navigation tool.

    GPS in the United States and Europe could also experience malicious jamming attacks, reinforcing the need for a backup alternative such as eLoran.