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A Learning Experience
September 27, 2014

A Learning Experience

My favorite bumper sticker this month: “Oh, no! Not another learning experience!”

After 20 years of putting together a European GNSS program, disappointment over the skewed launch of the first fully operational Galileo satellites is palpable and widely felt. For end users, it is uniformly bad news, and no system provider that sincerely wants to achieve interoperability and robustness in a system of GNSS systems can relish the European program’s current difficulties.

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By Inside GNSS
OCX Program Restructured, Delayed Again
September 24, 2014

OCX Program Restructured, Delayed Again

Editor’s Note: An exclusive interview with Gen. Hyten is available here with more details.

Details are emerging about another restructuring of the contract for the new GPS ground system, a deal that pushes completion of the project back another two years and recasts the remaining work to fit within the Air Force’s strained financial profile.

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By Dee Ann Divis
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IUS_PubLet_Header.jpg
August 8, 2014

Publisher’s Letter

Transformative.

My first encounter with an unmanned aerial vehicle, or UAV, was at the German Aerospace Center (DLR) in Oberpfaffenhofen Germany. Here, I watched in awe as a small quadrotor operated in an indoor flight testing “holodeck,” complete with an array of high-frequency strobe/camera units designed to log, stream and visualize precise position and attitude for rapid 3D mapping.

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By Inside GNSS
The Next Big Mac
July 27, 2014

The Next Big Mac

Here’s the coolest “technology-meets-ingenuity-meets-sustainable-economics” story that I’ve heard in a long time: the International Sun-Earth Explorer-3 (ISEE-3) Reboot Project, a crowd-funded rescue mission to repurpose a 36-year-old NASA spacecraft.

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By Dee Ann Divis
New Leaders at the GPS Helm
July 21, 2014

New Leaders at the GPS Helm

Washington, D.C., has a peculiarity of seasons. While most of the world marks the shifts between winter and spring, summer and autumn, the politicos on the streets of the U.S. capital count the passage of time in two-year increments.

New operatives and appointees flock to the centers of power in the early days of each administration and the opening of each Congress, then migrate to friendlier climes as congressional elections loom and the administration winds down — as it is now.

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By Dee Ann Divis
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GNSS Position Estimates

GNSS Position Estimates

Q: How do measurement errors propagate into GNSS position estimates?

A: Not surprisingly, GNSS positioning accuracy is largely dependent on the level of measurement errors induced by orbital inaccuracies, atmospheric effects, multipath, and noise. This article discusses how, specifically, these errors manifest as position errors.

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By Inside GNSS
Papering Over Safety Gaps
May 18, 2014

Papering Over Safety Gaps

Well, I could have taken up the subject of the deteriorating condition of U.S./Soviet, excuse me, U.S./Russian relations. But there are only so many windmills that I have time to tilt at.

So, rather than tracing the dissolution of bilateral GNSS cooperation in the wake of Russia’s reclaiming the Crimea and, who knows, perhaps eventually a large swath of eastern Ukraine, I thought I’d turn to an only slightly more remediable issue — GNSS carriage requirements.

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By Inside GNSS
Collective Detection of Multi-GNSS Signals
May 6, 2014

Collective Detection of Multi-GNSS Signals

Clockwise from left: (a) article equations, (b) the probablility of acquiring a single satellite to the power of the nyumber of satellites in view, (c) Indoor scenario of signal collection at ISAE navigation lab, Toulouse

Working Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Prof. Dr.-Ing. Günter Hein, head of Europe’s Galileo Operations and Evolution.

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By Inside GNSS
How do you compute a relative position using GNSS?

How do you compute a relative position using GNSS?

Q: How do you compute a relative position using GNSS?

A: In many applications the absolute position of an object is less important than the relative position to other objects in the vicinity. An obvious example is a collision avoidance system, wherein the proximity of nearly vehicles is much more important than whether the vehicles are located on street “X” or “Y.”

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By Inside GNSS
It’s Spring, and EGNOS Is in the Air

It’s Spring, and EGNOS Is in the Air

Europe has been talking up its European Geostationary Navigation Overlay Service (EGNOS, for short) — and why shouldn’t it? Talking about Galileo doesn’t get satellites off the ground. EGNOS, on the other hand, is up and running, and has been since 2009. If the object is to build confidence in European savoir faire, why not talk about a real success like EGNOS?

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By Peter Gutierrez
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