Column

January 26, 2017

No Sudden Moves

As with the notion of “disruption,” unpredictability can be useful. A move in chess or go, for instance. Or in the case of cuisine — say, when usurping Taco Thursday with chicken tagine. Even in negotiations, an unanticipated gambit can change the outcome positively.

Sometimes, of course, unpredictability is in the immanent nature of things. Despite advances in meteorological technology and science, weather continues to prove fickle. Foreknowledge of earthquakes remains difficult to pin down in space and time.

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By Inside GNSS
January 24, 2017

State of Play in China

The BeiDou Navigation Satellite System (BDS) is China’s contribution to the world in the domain of Global Satellite Navigation System (GNSS). The BDS is being developed by the Chinese government, mainly through military departments, with key considerations for China’s national security, economic interests and social progress.

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By Ingo Baumann

Is it possible to build a low-cost system to detect and locate a single GNSS jammer in near-real time?

Q: Is it possible to build a low-cost system to detect and locate a single GNSS jammer in near-real time?

A: GNSS jammers are an ongoing threat to the reliable use of GNSS. The problem of geolocating GNSS jammers can be addressed using a time-difference-of-arrival (TDOA) processing technique; however, this problem is quite different than geolocating jammers in other radio frequency systems. The two main differences are:

(1) No GNSS are available to use as a timing reference.

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By Inside GNSS

GPS Roundup: Congress Reopens for Business

Washington has seen a lot of transitions, so even amidst political controversy it’s generally business as usual.

For the GPS community that business, at least in the near term, will likely center on changes in federal leadership — with many key appointments, like a new Secretary of the Air Force, still to be determined. In addition — even at this early stage when new lawmakers are still trying to find their offices — there are issues and opportunities worth watching in emerging legislation.

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By Dee Ann Divis
November 30, 2016

Exit, Pursued by a Bear

American Election 2016 — now that was something, wasn’t it?

A national unpopularity contest. Sort of Commedia dell’arte meets Monty Python, directed by Todd Phillips, with a cameo appearance by Berlusconi.

Did we find it risible? Oh, yes, but were those tears of laughter, sorrow, or disbelief?

So, while we are collectively unpacking the meaning and nonsense from two years of political theater and telling each other our fortunes for the next four, what does it portend for GNSS?

Well, the tea leaves are a little unclear.

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By Dee Ann Divis

How Will GNSS Fare Under a Trump Administration?

With the Republican Party now entirely in charge of Washington’s prime policy real estate the neighborhood is going to change. The current residents are warily watching the newcomers take measurements for a major remodel of agencies, lobbying rules, national priorities, and international relationships, and everyone is assessing the implications of the new landscape.

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By Dee Ann Divis

Challenges of Ray-Tracing for GNSS Applications

Figures 5 – 8

Q: What are the challenges of ray-tracing for GNSS applications?

A: Simulating the propagation and reception of GNSS signals in complex environments is a challenging task. Indeed, the user always has to trade off between the computation time and the reliability of the output. Moreover, the motion of GNSS satellites, atmospheric effects, and building geometry are always difficult to model.

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By Inside GNSS