Archives

Are You a Professional? Follow-up Letters and Using GIS for Commercial Real Estate Market Research

August 31, 2010 - By

I’m happy that last week’s article titled “Are You a Professional?” evoked responses from readers. I thought I’d share a couple of the responses I received. Also, I've included a good piece on using GIS for commercial real estate market research. read more

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Solar Activity and Powerpoint Presentations

August 4, 2010 - By

You might have heard reports this week about a solar storm this week. This is part of the new solar cycle (Solar Cycle 24) that I’ve written about several times. I want to periodically touch on this subject as the solar activity is going to increase over the next few years, and if the solar activity (geomagnetic storms, not sunspots) is severe enough, it will have an effect on GPS accuracy and tracking. Here’s the scoop on this week’s solar activity. read more

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GPS World: 20 Years Young, 1990-2010

August 1, 2010 - By

A look at how things have changed since GPS World began, with participation by CAST Navigation, Hemisphere GPS, ITT, Rakon, and Spirent Federal. read more

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Out in Front: EGNOS Up

August 1, 2010 - By

We now definitively declare “curtain up!” on the second act of the human and technological drama, Interoperable Global Navigation Satellite Systems, by many authors, directors, and actors, upon the global stage. It happened on August 2 with removal of the message 0 (“Do Not Use in aviation”), by the European Satellite Services Provider, from the European Geostationary Navigation Overlay Service (EGNOS) signal. It enables EGNOS use for en-route and lateral guidance approaches. read more

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The System: Three’s the Challenge

August 1, 2010 - By

A small variance in the L5 signal, which remains well within signal specifications and will not affect pseudorange measurements, may show some impact on triple-frequency combinations of the signal’s carrier phase in high-precision applications. Observations suggest a temperature-dependent line bias in one or more carriers as a likely cause of the observed variation in the tri-carrier combination of L1, L2, and L5. read more

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The System: An L5 Surprise

August 1, 2010 - By

Researchers at the German Aerospace Center say they have found a small variance in the L5 signal on IIF-1. The signal variation results in no more than a 5-centimeter error with a predictable periodicity of about six hours. The GPS Wing is studying the issue and expects to resolve it before setting the satellite healthy, in another month or so according to the schedule. read more

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How Flat Can You Incline?

August 1, 2010 - By

The next time a defensive safety brings down an opposing wide receiver at Commonwealth Stadium, both will land on a very well-prepared piece of real estate. read more

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