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| Innovation: Making a Difference with GPS
| One of the difficulties with RTK-style positioning is resolving carrier-phase ambiguities. If you time-difference sequential carrier-phase measurements, the ambiguity actually disappears, and you can determine accurate relative positions using time-differenced carrier-phase measurements. But there are some caveats.  | | | Innovation: Tsunami Detection by GPS
| | Recent investigations have demonstrated that GPS might be an effective tool for improving the tsumani early-warning system through rapid determination of earthquake magnitude using data from GPS networks. A less obvious approach is to use the GPS data to look for the tsunami signature in the ionosphere. | | | Innovation: Brainy Positioning
| | Primarily developed for computing applications, such as pattern recognition, neural networks have been adapted for use in several fields of science, including geodesy. Those adaptations are needed because usually the situations and problems encountered in computer science are different from those in other fields. Geodesy is no exception. | | | Innovation: Network RTK
| | An innovative filter technique significantly extends the number of reference stations that can be supported for network RTK positioning under modernized GNSS. | | | Innovation: Stochastic Models for GPS Positioning — An Empirical Approach
| | When processing GPS data, we should not only try to model the deterministic part of the measurements; we should also try to account for their stochastic behavior, which is possible through use of the covariance matrix. Here, the authors present an empirical approach for building the covariance matrix of observations, with the ultimate goal to improve the quality of GPS data processing. | | | Innovation: Phase Wind-Up Analysis
| | A circularly polarized antenna's phase depends directly on the antenna's orientation with respect to the signal source. As a result, the observed carrier phase depends on the relative orientation of the transmitting and receiving antennas as well as the direction of the line of sight between them. Changing the receiver antenna orientation changes the reference direction and thus the measured phase. | | | OpenSource GPS: Part I, Hardware
| | PDF: The OpenSource GPS project has developed an economical hardware and software platform specifically for educational purposes. In this month?s column, two of the project?s leaders, present part one of a two-part article on the project. This month, they will discuss the hardware component, built around the Zarlink GP2015/GP2021 chipset. | |  MORE ARTICLES
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| Bringing All GNSS into Line
| | The introduction of new GNSSs requires updating the AGPS-only solution to add support for new GPS bands, new GNSSs, and to enhance accuracy, sensitivity, and availability. | | | Innovation: Opportunistic Navigation
| | The signals from AM stations can be used to determine the position of a mobile receiver with respect to a reference receiver using time difference of arrival (TDOA) measurements and a supplementary link between the two receivers. A team from the U.S. Air Force Institute of Technology describe simulations and real-world experiments they carried out using a software-defined radio receiver to test the feasibility of AM radio TDOA measurements for positioning and navigation. | |
| | Innovation: Any Questions? The International GNSS Service
| | The IGS was established in 1994 in order to provide the highest quality GNSS data and products in support of Earth science research, multidisciplinary applications, and education. It was and is still the aim of the IGS to advance scientific understanding of the Earth system components and their interactions, as well as to facilitate other applications benefiting society. | | | Approach with Precision
| | New ground-based augmentation systems at or near airports offer the potential of new or improved capabilities, as well as cost reduction for existing airspace system infrastructure. The authors tested a prototype using a multimode GPS receiver that converts differentially corrected signals to the airplane's instrument system, enabling more precise autolandings. | | | EGNOS Takes Flight
| | Tests of the European Geostationary Navigation Overlay Service (EGNOS) indicate the system's future capabilities as a navigation aid for the aeronautical community, particularly in approaches to mountain-based airports and other challenging environments. | | | Assistance When There's No Assistance
| | Long-Term Orbit data, obtainable over the Internet, can enable a locatable cell phone or PDA to position itself accurately for as long as four days without further assistance. | | | Myths and Realities of Anywhere GPS
| | AGPS does not mean works "Anywhere" GPS. Accurately determining what will work for any given application requires a properly designed test procedure. | | | Integrity Hits the Road
| | Low-cost sensors and a Horizontal Trust Level (HTL) enable mobile-terminal applications requiring continuous quality of service in positioning and integrity. | | | MORE ARTICLES
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| Expert Advice — Do We Have Data?
| | It seems that every week a new and usually glowing market report appears on GPS. As a marketing professional, I naturally take a keen interest in the data that can be gleaned therein. Such reports are an essential source of information for both industry participants and investors. | | | Expert Advice — Prepare for GIOVE-B Liftoff
| | A at the end of this month, on the 27th of April, Europe will add a new cornerstone to the Galileo programme and to global satellite navigation as a whole. GIOVE-B, the second Galileo In-Orbit Validation Element (GIOVE) satellite, will rise into a medium-Earth orbit aboard a Soyuz launcher from the Baikonur cosmodrome in Kazakhstan. | | | Expert Advice — In Defense of SiRF
| | On February 11, GPS World's Navigate! e-news daily reported that a Pennsylvania law firm made SiRF Technology the object of a class-action lawsuit following the company's February 5 fourth-quarter earnings report. On February 14, we reported a second action. More than a dozen firms have now filed against SiRF. | | | Expert Advice — GLONASS Business Prospects
| | Similar in many aspects to GPS, GLONASS has performed much less successfully on a commercial scale, failing — so far — to create significant business worldwide. Today, however, the commercialization of GLONASS has taken a new and more promising direction, receiving strong encouragement from the Russian government. We look forward to GLONASS being completely restored to its full operational capabilities within the next few years, and we are certain that this time GLONASS will create successful business opportunities worldwide. | | | Expert Advice — Accuracy in More than Position Only
| | Terry McGurn's closing observations in his November 2007 column on accuracy evoke a grateful reaction from me. Glib summaries of performance are incomplete. Pinpointing moving objects within ever-smaller fractions of size is not always most important; frequently, it's knowing where they'll be a little later. | | | Leadership Talks — European Industry Group
| | We spoke with John Wilde (JW), director at the independent technical consultancy DW International Limited about the future of Galileo. | | | Expert Advice — eLoran, Superhero Sidekick!
| | Enhanced Loran, eLoran, is GPS's new best friend and superhero sidekick. It is independent of GPS with dissimilar failure modes and delivers complementary levels of performance to multi-modal users. | | | Expert Advice — Pointed Opinions
| | We present a selectively abridged version of the published minutes of the second meeting of the National Space-Based Positioning, Navigation and Timing (PNT) Advisory Board, held October 4-5 in Washington, D.C. The full minutes are posted for public review at www.pnt.gov. Bold headings have been added to indicate topics and to facilitate reading. Other than deleting some discussions entirely and others partially to get the original document from 18,000 words down to this 4,000-word version, no other changes have been made to the minutes. | | | Leadership Talks — The A-GNSS Backbone
| | Jari Syrjarinne, technologist in GNSS systems research at Nokia Technology Platforms, spoke with editor Alan Cameron. Nokia recently offered $8.1 billion to acquire digital mapper Navteq. | | | MORE ARTICLES
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| Galileo Validation
| | The GIOVE-A satellite broadcast Galileo's first signals on January 12, 2006. GIOVE-B is scheduled for launch on April 14, 2008. The authors describe generation of the first Galileo navigation messages, operational and performance aspects, and signal improvements. Some improvements have been already identified, and their implementation is ongoing. | | | Apples to Apples
| | Many products have similar performance specifications, but specified performance and measured performance can vary widely. Here, the authors describe how a standard methodology precisely defines acquisition, tracking, and reacquisition, using specific input signals to test each quantity. | | | Directions 2008: Future Critical
| | Lieutenant General Michael Hamel (MH), Commander of Air Force Space Command?s Space and Missile Systems Center (SMC) in Los Angeles, California, spoke with contributing Editor Don Jewell (DJ) about changes to the space acquisition process, separation of the GPS ground and space segments, and the next generation of user equipment. | | | The Almanac
| | Orbit Data and Resources on Active GNSS Satellites | | | DIRECTIONS 2007: System Design & Test
| | In 2007, we will witness an early glimpse of the magnitude of GNSS promise with satellite launches in GPS, GLONASS, Galileo GIOVE-B, and Compass. Today, customers all over the world understand the benefits of GNSS innovation. When they choose products that include expanded GNSS capabilities, they will continue to expect to improve the way they live and work. | | | MORE ARTICLES
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| Letters to the Editor — May 2008
| | Joint Control of GPS; SiRF Suits | | | Out in Front — Re-Up for Leaders
| | me of little faith. I had thought, after concluding this month?s 50+ Leaders to Watch article, to quietly wrap it up and put it away on the shelf. Not to be continued next year. We?ve had a three-year run, and it?s been a good one. But how many leaders can there be, worthy of watching? You get to 150+, you feel a bit long in the tooth. But the GNSS community carries much more breadth, depth, enthusiasm, and creativity than I had grokked, even after eight years of covering nearly every aspect of it. | | | Letters to the Editor — April 2008
| | What Were They Thinking?; More on 32; Anomaly Straight Talk; WAAS and ADS-B | |
| Out in Front — Hit the Road, Jack
| | We may have neglected those other great mechanical metaphors of our times, the automobile and the delivery truck. We may hardly ever think about the defining institution of our age, the highway — and just how GPS-enabled all those rolling boxes and sprawling concrete ribbons could be. | | | Letters to the Editor — March 2008
| | Machine Control; eLORAN; Military Review; Multi-Source PNT | | | Out in Front — Leap of Faith
| | The high priesthood of the Galileo program lashed on the believers attending the Munich Satellite Navigation Summit with the amen verse of "Galileo is back on track," admonishing them to keep the faith and to put that faith into good works. These good works amount to building the applications and the user equipment well in advance. | | | Out in Front — New Hand at the Helm
| | You might think it's easy standing up here all the time, spouting off out in front and editing and such. It's not. It's not easy. What makes it considerably less difficult is the broadbased and unstinting support that the editorial staff receives from the business office. Headed by, it can now be said, publisher Kristina Panter. | | | Out in Front — Opportunity Abounds
| | When I wrote in November that "Di Qui?s article on geoencryption with Loran represents to my knowledge the first article ever published in this magazine that is not about GPS or some other GNSS," I completely neglected the wealth of material that Richard Langley has provided in the Innovation column over the years.
| | | Out in Front — Maxing with the Millennials
| | To gain a grain of understanding of my kids, and in the name of researching future GPS markets, I attended a session on maximizing mobile media use by the millennials at CTIA Wireless in San Francisco. Who are the millennials? Loosely, individuals today between the ages of 12 and 27, also known as Gen Yers, echo boomers, or the iGen (Internet generation). | | | MORE ARTICLES
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| Galileo, GLONASS, and GPS
| | by Javad Ashjaee, President & CEO, Javad Navigation Systems | | | Level Playing Field for Industry
| | by Paul Verhoef, Head of Unit for Galileo and Intelligent Transport, Directory General for Energy and Transport, European Commission | | | The Consumer Benefits
| | by Bruce Peetz, Vice President, Advanced Technology and Systems, Trimble | | | A Global System Evolves
| | by Mike Rizzo, Director, Navigation Systems, Boeing Air Force Space Systems | | | Three Better than One, or Two
| | by Eduardo Falcon, Vice President-Product Development, Topcon Positioning Systems, Inc. | | | Accelerate into the Mainstream
| | by Kanwar Chadha, Founder, SiRF Technology | | | No Longer Talking — Doing
| | by Tony Murfin, Vice President, Business Development, NovAtel | | | MORE ARTICLES
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| Test Satellite Officially Joins GPS Constellation
| | In a general message to all GPS users released today, the GPS Operations Center announced that it will be adding test satellite SNV23/PRN32 into the broadcast almanacs on June 27, 2007. | | | Old Block IIA Sat Reactivated for Tests
| | SVN23, the first Block IIA satellite to be launched (as PRN23), has been reactivated as PRN32. This satellite was launched on November 26, 1990, and initially decommissioned on February 13, 2004, after more than 13 years of service. SVN23/PRN32 is in slot E5 and is operating on its Rb2 clock. | | | GPS III Faucet Opened: $50M Design Contracts Awarded
| | Co-competitors Lockheed Martin Space Systems Corp. and Boeing Co. each received a $49,999,000 cost-plus-fixed fee contract modification to accomplish a GPS III system design review (SDR) in March 2007, towards a key decision point B in June, 2007: the award of a multi-billion dollar development contract for building GPS III. | | | Air Force GPS Wing Commander on Constellation Status
| | Colonel Wesley A. Ballenger, Jr., Commander, Global Positioning Wing of the U.S. Air Force, spoke with GPS World editor Alan Cameron | | | GPS + Modernized GPS + Galileo—Signal Timing Biases
| | PDF: New GPS signals and the future Galileo signals are somewhat different than the legacy signals broadcast by GPS satellites today, so new ways of accounting for biases will be needed. In this month?s column, Chris Hegarty, Ed Powers, and Blair Fonville discuss this problem. | | | New, Improved GPS
| | The GPS Legacy Accuracy Improvement Initiative has improved the accuracy of the Kalman filter state estimates, the accuracy of the broadcast ephemeris and clock parameters, and the ability to observe performance of GPS satellites. | | | Directions 2006 (PDF)
| | Directions 2006 | | | DSB Report Released
| | The Defense Science Board Task Force of the Office of the Under Secretary of Defense has issued its report on The Future of the Global Positioning System. | | | Future Navigation Needs Your Input
| | L1C Phase II interviews have taken place in Japan, Russia, Germany, the United Kingdom, and Canada, and now get underway in the United States. | | | MORE ARTICLES
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| Galileo Validation
| | The GIOVE-A satellite broadcast Galileo's first signals on January 12, 2006. GIOVE-B is scheduled for launch on April 14, 2008. The authors describe generation of the first Galileo navigation messages, operational and performance aspects, and signal improvements. Some improvements have been already identified, and their implementation is ongoing. | | | Innovation: Time for GIOVE-A
| | One candidate clock for future Galileo satellites is the European Rubidium Atomic Frequency Standard. Two of these clocks are flying onboard GIOVE-A. | | | Meet GIOVE-A
| | Galileo satellites must operate in a harsh environment more than 20,000 kilometers above the Earth, through the intense Van Allen electron belt. Key team members describe the design, manufacture, launch, and commissioning of the demonstration satellite GIOVE-A. | | | Galileo Signal Experimentation
| | The GIOVE-A satellite, transmitting the full set of modulations envisaged for Galileo (except MBOC), presents the first opportunity to assess performance of the future signals in real-life conditions, under interference and multipath. Signal, receiver, and sensor-station experimentation demonstrate that all Galileo signals perform significantly better than GPS-C/A with regard to noise and multipath performance. | | | Ready to Receive: Developing a Professional Antenna for Galileo
| | Can a multi-band antenna cover all the carriers necessary in a modern GNSS, or does the advent of Galileo demand a true wideband technology? The mechanical and resultant electrical symmetry of such a combined GPS+Galileo antenna must provide the phase-center stability with direction of signal arrival necessary for geodetic grade performance. The authors discuss the relative merits of different technologies and offer a detailed analysis of their candidate antenna design. | | | GIOVE'S Track
| | In preparation for the deployment of the Galileo system, the European Space Agency (ESA) began development in 2003 of two Galileo In-Orbit Validation Element (GIOVE) satellites: GIOVE-A and GIOVE-B. | | | Innovation: Searching for Galileo
| | Researchers sought to determine whether the GIOVE-A L1 binary offset carrier signal could be acquired and the PRN codes uncovered using codeless acquisition and statistical signal processing techniques. The short answer: Yes! | | | Galileo to Launch First Satellite, GIOVE
| | The Big Five European nations have reached an interim financial agreement on Galileo’s first industrial phase. | | | Early Results Are In
| | The Galileo Test Receiver will enable developers to add other frequencies and services in the future, and a new single-channel L1/E5a Galileo transmitter lets designers perform in-lab demonstrations and signal-in-space testing. | |
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| DIRECTIONS 2007: System Design & Test
| | In 2007, we will witness an early glimpse of the magnitude of GNSS promise with satellite launches in GPS, GLONASS, Galileo GIOVE-B, and Compass. Today, customers all over the world understand the benefits of GNSS innovation. When they choose products that include expanded GNSS capabilities, they will continue to expect to improve the way they live and work. | | | Expert Advice — Managing the GPS Constellation for Today's Needs
| | For many, GPS is at its best performance ever, with 29 satellites in orbit and user range errors at their lowest levels in years. Yet for others, GPS performance falls short of expectations. | | | Expert Advice — What's New: ION GNSS 2006
| | This year's ION GNSS will be one of the most exciting conferences yet. | | | Expert Advice — Quick Look at Galileo ICD
| | The Galileo Joint Undertaking released the Galileo Open Service Signal-In-Space (SIS) Interface Control Document (ICD) on May 23, with the announced intent of fostering standardization for mass-market development of the Galileo Open Service (OS) for the benefit and the promotion of the European GNSS programs.
| | | Expert Advice — The Case for eLORAN
| | The world's shipping industry is experiencing a period of strong growth with seaborne trade at record levels and |
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