Design & Test

The System: U.S. DoD, DoT Tell FCC No LightSquared

February 1, 2012By

Ashton Carter, U.S. deputy secretary for Defense, and John Porcari, deputy secretary for Transportation, have written an official letter to the assistant secretary of Commerce stating that “there appear to be no practical solutions or mitigations that would permit the LightSquared broadband service.” Carter and Porcari are co-chairs of the National Executive Committee for Space-Based Positioning, Navigation, and Timing. This... read more

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Patch Antennas for the New GNSS

February 1, 2012By

Small ceramic patch elements offer nearly perfect single-frequency receive characteristics and have become the standard for GPS L1 antennas. However, the new generation of GNSS receivers now being introduced track many satellites in multiple constellations. Are these narrow-band devices up to the task for wider bandwidths? read more

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Out in Front: When the Gavel Comes Down

February 1, 2012By

Perhaps you don’t track suspected criminals in your spare time, nor do you design or supply a GNSS product that does so. Still, the fresh Supreme Court ruling on GPS use for this purpose reverberates for you, in ways yet unknown. The most interesting part of the court’s ruling pops up in a somewhat open-ended “what if” comment concerning future issues that at least one justice thinks the court should address. read more

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Engineers Invited to Explore GNSS Filters at JAVAD GNSS

January 3, 2012By

Javad Ashjaee, president and CEO of JAVAD GNSS, invites engineers "who want to roll up their sleeves" to a working session at his company's San Jose, California facility on Tuesday, January 17, to "find solutions and discuss technical details" related to the LightSquared/GPS conflict. read more

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The System: Galileo in Its Glory

January 1, 2012By

  GALILEO PROTOFLIGHTMODEL satellite began transmitting E1 and E5 signals in early December. ESA reports them well within power and shape specifications, and suited for interoperability with GPS. The Galileo ProtoFlightModel (PFM) in-orbit validation (IOV) satellite GSAT0101 began transmitting E1 signals on December 10 using the E11 ranging code, and E5 signals early on December 14. Launched at the same... read more

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Innovation: Know Your Enemy

January 1, 2012By
Inno-Opener

Signal Characteristics of Civil GPS Jammers
GPS jamming is a continuing threat. A detailed understanding of how the available jammers work is necessary to judge their effectiveness and limitations. A team of researchers from Cornell University and the University of Texas at Austin reports on their analyses of the signal properties of 18 commercially available GPS jammers. read more

Straight Talk on Anti-Spoofing: Securing the Future of PNT

January 1, 2012By
Spoofing

Disruption created by intentional generation of fake GPS signals could have serious economic consequences. This article discusses how typical civil GPS receivers respond to an advanced civil GPS spoofing attack, and four techniques to counter such attacks: spread-spectrum security codes, navigation message authentication, dual-receiver correlation of military signals, and vestigial signal defense. Unfortunately, any kind of anti-spoofing, however necessary, is a tough sell. read more

Expert Advice: Test-Based Civil Receiver Certification

December 1, 2011By

Disaster-preparedness plans recognize the individual’s role in his or her own survival. When storms approach, have water, food, and basic survival gear on hand. It takes time for help to arrive. The civil GPS industry faces an oncoming storm of interference, and the receiver is the first line of defense. As we integrate GPS into all facets of our lives and infrastructure, we become more subject to disruptions, both unintentional and intentional. Newark International Airport now sees several jamming events per day. In Taiwan, one airport experiences an average of 117 events per day! read more

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