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All posts from GPS World staff

  • Expert Advice: The Strategic Significance of Compass

    Dec 01, 2010 No Comments

    Scott Pace By Scott Pace On November 1, 2010, China’s state news agency reported that the sixth Compass satellite was launched from the Xichang Satellite Launch Center. This was the fourth Compass satellite put into orbit this year, following launches in January, June, and August. Joining the Unit...

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  • The System: QZSS Puts L1C on the Air

    Dec 01, 2010 No Comments

    QZSS Puts L1C on the Air JAVAD Receivers Track the First Truly Interoperable Signal JAVAD GNSS engineers in Moscow have released plots of the C/A, L2C, L5, SAIF, and the new L1C signals broadcast by Japan’s QZSS Michibiki, the first satellite to transmit L1C. The company stated that all of its cur...

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  • GNSS RF Compatibility Assessment: Interference among GPS, Galileo, and Compass

    Dec 01, 2010 No Comments

    By Wei Liu, Xingqun Zhan, Li Liu, and Mancang Niu A comprehensive methodology combines spectral-separation and code-tracking spectral-sensitivity coefficients to analyze interference among GPS, Galileo, and Compass. The authors propose determining the minimum acceptable degradation of effective carr...

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  • J911: Fast Jammer Detection and Location Using Cell-Phone Crowd-Sourcings

    Nov 01, 2010 No Comments

    By Logan Scott Inexpensive, readily available GPS jammers constitute a threat to safety, national infrastructure, and industry revenue streams. Cell phones could incorporate GPS jam-to-noise (J/N) ratio detectors to provide timely interference detection and effective localization, with a flexible an...

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  • Expert Advice: Block IIR Lifetimes and GPS Sustainment

    Nov 01, 2010 No Comments

    Willard Marquis (left) and J. David Riggs In 2009, a Government Accountability Office (GAO) report claimed that the GPS constellation was extremely vulnerable to failure, and a recent September 2010 GAO follow-up continues to make that assertion. In this article, we present the technical data to con...

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  • Where Time and Space Meet

    Nov 01, 2010 4 Comments

    Sensor Modeling and Sensitivity Analysis for a Next-Generation Time-Space Position Information System By Mark Smearcheck and Michael Veth, Air Force Institute of Technology Increasing availability and performance of state-of-the-art navigation sensors motivates the need for a highly accurate referen...

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  • The System: Galileo PRS Delivery in Question

    Nov 01, 2010 No Comments

    Once envisioned to orbit 30 satellites, Galileo’s constellation has over time been reduced to a planned, though still not space-borne, four initial satellites plus 14 operational satellites for a total of 18. The European Space Agency (ESA), under direction of the European Commission (EC), confirm...

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  • On the Edge: Tracking, Testing

    Nov 01, 2010 No Comments

    By Lukasz Bonenberg and Craig Hancock One-hundred-twenty meters of test track, designed for repeatable dynamic position testing, run along the roof of the new Nottingham Geospatial Building at the University of Nottingham, UK. The figure-eight track provides an optimal controlled environment with te...

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