Magazine Department

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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SAGAIE

Scintillation — rapid RF signal frequency and amplitude changes due to signal propagation path changes and phase shifting caused by solar turbulence in the ionosphere — is well known in the GNSS community. However, conclusive scientific studies that cover the whole extent of the question are hard to find. Galileo In-Orbit Validation Experiment (GIOVE) data processing confirmed the effects of scintillation on GNSS receivers, as described in the paper by J. Giraud listed in the Additional Resources section near the end of this article.

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By Inside GNSS
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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
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

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

A Universal GNSS Software Receiver Toolbox

In recent years, numerous, relatively inexpensive hardware platforms for conducting scientific research using the software defined radio (SDR) paradigm have become commercially available. The Manufacturers section near the end of this article lists examples of several of these. In turn, this has spurred universities and research groups around the world to adopt this technology for advanced GNSS signals-based research and development.

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By Inside GNSS
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