More Satellites, More Sensors Take Urban Navigation Downtown and Deep Indoors By Frank van Diggelen As we all know, GPS is practically perfect in every way — as long as it’s outside and unobstructed. Even cell phones can now produce meter-level accuracy under open sky. There are still many defic...
Read More →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...
Read More →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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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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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...
Read More →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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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...
Read More →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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