Design & Test

Part 1: The Origins of GPS, and the Pioneers Who Launched the System

May 1, 2010By
Mathematician Bill Guier (l) and physicist George Weiffenbach (r), told APL Research Center director Frank T. McClure (c), about their success using Doppler tracking for satellites. “McClure’s brain started going into fast forward,” remembered John Dassoulas. “Knowing the navigational challenges the U.S. Navy faced, McClure said, ‘Well, if you can find out where the satellite is, you ought to be able to turn that problem upside down and find out where you are.’ “

The original system study, the key innovations, and the forgotten heroes of the world’s first — and still greatest — global navigation satellite system. True history, told by the people who made it. Part One of a Two-Part Special Feature. read more

Innovation: Accuracy versus Precision

May 1, 2010By

A Primer on GPS Truth
True to its word origins, accuracy demands careful and thoughtful work. This article provides a close look at the differences between the precision and accuracy of GPS-determined positions, and should alleviate the confusion between the terms — making abuse of the truth perhaps less likely in the business of GPS positioning. read more

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Aeroflex Introduces Portable Positional Simulator for GPS/Galileo Receivers

April 12, 2010By

A-Aeroflex has introduced the GPSG-1000, a portable GPS and Galileo positional simulator. The GPSG-1000 is lightweight and configurable. It fills a gap in the market by providing a low-cost 12-channel test set that creates three-dimensional simulations, A-Aeroflex said. read more

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Innovation: GPS by the Numbers

April 1, 2010By

A Sideways Look at How the Global Positioning System Works
In his 200th Innovation column, Contributing Editor Richard Langley takes a look at GPS by the numbers, getting a sense of how GPS works by examining the key numbers that govern its remarkable capabilities, from zero to pi and beyond. read more

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Galileo Test User Receiver

April 1, 2010By
FIGURE 1. C/N0 plot with nine satellites and all five Galileo signal types: L1BC (green), E6BC (blue), E5a (red), E5b (yellow), and E5 Altboc (purple).

A fully stand-alone, multi-frequency, multi-constellation receiver unit, the TUR-N can autonomously generate measurements, determine its position, and compute the Galileo safety-of-life integrity. read more

The System: Vistas from the Summit

April 1, 2010By

“This is an event where one gets one’s goals for the next year.” Paul Verhoef, program director for satellite navigation programs of the European Commission, may have exaggerated for effect, and for the benefit of his audience and hosts at the Munich Satellite Navigation Summit in March. But not by much. The conference, now in its eighth year, has assumed... read more

Innovation: Hybrid Positioning

March 1, 2010By
Figure 11. The electronic car used in the test.

A Prototype System for Navigation in GPS-Challenged Environments
A team of Australian and U.S. researchers have integrated a ground-based system with GPS and INS to create a hybrid system that provides precise and accurate position information continuously in a variety of environments where GPS alone comes up short. read more

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On the Edge: Sharing GNSS Wealth

March 1, 2010By

Last year I helped coordinate a three-week workshop for 50 scientists from 15 African countries, introducing the basics of GPS for applications with socioeconomic benefits and scientific exploration. Held in Trieste, Italy, the workshop was quite successful, producing new initiatives on the African continent. We repeat the workshop next month, 
April 6–24, again in Trieste. read more