Getting a Better Handle on the Biases
Mar 1, 2008
By:
Don Kim, Richard B. Langley
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How accurate modeling of atmospheric effects coupled with an ionosphere-free ambiguity resolution process results in successful long-range RTK.
Sensing Land and Ice from Low Earth Orbit
Oct 1, 2007
By:
Scott T. Gleason
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An out-of-the-ordinary application of GPS uses signals reflected off the Earth's surface to sense land and ice, as well as the ocean surface, from low Earth orbit. Analysis of these signals holds great promise for measuring ocean roughness, ice conditions, vegetation cover, and even soil moisture.
Finding Your Way with AM Signals of Opportunity
Jul 1, 2007
By:
Jonathan McEllroy, John F. Raquet, Michael A. Temple
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The signals from AM stations can be used to determine the position of a mobile receiver with respect to a reference receiver using time difference of arrival (TDOA) measurements and a supplementary link between the two receivers. A team from the U.S. Air Force Institute of Technology describe simulations and real-world experiments they carried out using a software-defined radio receiver to test the feasibility of AM radio TDOA measurements for positioning and navigation.
Reception and Analysis of Signals from GIOVE-A
Jun 1, 2006
By:
Mark L. Psiaki, Todd E. Humphreys, Shan Mohiuddin, Steven P. Powell, Alessandro P. Cerruti, Paul M. Kintner, Jr.
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Researchers sought to determine whether the GIOVE-A L1 binary offset carrier signal could be acquired and the PRN codes uncovered using codeless acquisition and statistical signal processing techniques. The short answer: Yes!
A System Analysis and Algorithm Development Research Tool for PCs
May 1, 2006
By:
J.K. Ray, S.M. Deshpande, R.A. Nayak, M.E. Cannon
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Each satellite signal and system has unique characteristics, making it a challenge for the GNSS research community to perform signal analysis in order to develop optimal algorithms to process and exploit these new signals.
Mar 1, 2006
By:
Chris Hegarty, Ed Powers, Blair Fonville
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New GPS signals and the future Galileo signals are somewhat different than the legacy signals broadcast by GPS satellites today, so new ways of accounting for timing biases will be needed.
Mar 1, 2006
By:
Chris Hegarty, Ed Powers, Blair Fonville
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PDF: New GPS signals and the future Galileo signals are somewhat different than the legacy signals broadcast by GPS satellites today, so new ways of accounting for biases will be needed. In this month?s column, Chris Hegarty, Ed Powers, and Blair Fonville discuss this problem.
A Hardware/Software Platform for Learning GPS
Feb 1, 2006
By:
Clifford Kelley, Douglas Baker
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PDF: This month's column features the second installment of a two-part article about the OpenSource GPS project. In Part II, project leaders Kelley and Baker overview the project software and present results of static and kinematic testing of the OpenSource GPS platform.
A Hardware/Software Platform for Learning GPS
Feb 1, 2006
By:
Clifford Kelley, Douglas Baker
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As we mentioned in last month's "Innovation" column, the OpenSource GPS Project began in 1995 as a noncommercial alternative to the pioneering GPS Builder product introduced by GEC Plessey Semicon-ductor in Swindon, United Kingdom. (GEC Plessey was acquired by Mitel Semiconductor, Ottawa, Canada, in 1998 and reborn in 2001 as Zarlink Semicon-ductor.) Based on the same family of GPS chipsets, OpenSource GPS provides students an opportunity to learn about GPS by experimenting with the hardware and software of a GPS receiver.
