201409 September/October 2014 Archives - Page 2 of 3 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

201409 September/October 2014

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
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

GNSS & Geodesy

Gerald Mader, National Geodetic Survey

In August, a group of scientists at the Scripps Institution of Oceanography reported that the severe drought gripping the western United States in recent years is causing a “uplift” in the western United States.

About the same time, governmental agencies were reporting widespread cases of land subsidence in California’s central San Joaquin Valley caused by overpumping of water from wells there.

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By Inside GNSS


Eugenia Acosta, an intern with Clearpath Robotics, unloads a Kingfisher unmanned vessel in preparation for a mission (top photo), the Kingfisher components and controller (bottom photo).

“Our products are robotic research platforms,” says Clearpath’s Meghan Hennessey. “These can be configured and programmed so that our customers can explore their particular areas of interest without all the cost and troubleshooting involved in actually building robots themselves.”

Hennessey says Clearpath platforms — which include the all-terrain Husky, the larger, tractor-like Grizzly and the waterborne Kingfisher — can be thought of as project kits.

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By Inside GNSS
September 17, 2014

Alison Brown: Tally Ho! The Hunt for GNSS Innovations

In 2005, Alison Brown was the first Sidney Sussex College woman alumna to be named as an honorary Fellow in recognition of her distinguished technical contributions. Pictured here with Keith Glover, now head of engineering at Cambridge University, who taught Brown control systems engineering, and Donald Green, her director of studies while she was an undergraduate.

SIDEBAR: Alison Brown’s Compass Points

On display in the Smithsonian’s “Time and Navigation” exhibit in Washington D.C. is the world’s first GPS-enabled cell phone. It was developed in 1995 by NAVSYS Corporation, a Colorado GNSS and inertial R& D company, as part of the push to build a national emergency notification system for mobile users, E911.

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By Inside GNSS


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
September 16, 2014

Harold Martin Returns to PNT NCO as Director

Harold “Stormy” Martin

Harold W. "Stormy" Martin III will be the new director of the National Coordination Office (NCO) for Space-Based Positioning, Navigation, and Timing (PNT), the focal point for federal agencies working out GPS policy issues.

Martin was the deputy director of the NCO and an Air Force colonel until this summer when he retired from the military. He will succeed Jan Brecht-Clark, who retired at the end of 2013. His start date as director has not been set.

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By Inside GNSS

ESA Outlines Efforts to Rescue Wayward Galileo Satellites

Orbits of the fifth and sixth Galileo satellites launched together on August 22, 2014, in red, compared to their intended position, in dashed green, and the position of the four IOV satellites launched in 2011 and 2012 in solid green. This view looks down over Earth’s South Pole, helping to illustrate how the two satellites’ orbital inclination relative to the equator is less than was intended ESA illustration.

The European Space Agency (ESA) released dramatic illustrations today (September 16, 2014) of the orbital locations of the two errant Galileo spacecraft launched on August 22, the intended orbit, and the locations of four In-Orbit Validation (IOV) satellites.

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By Inside GNSS