GPS Satellites Moved for More Robust, Accurate Signals

A news article from Inside GNSS reports:

By next June, the United States GPS constellation will attain the most optimal geometry in its 42 year history. Over time, that means a more robust signal, more accuracy and more reliability in GPS-challenged environments.

This is an interesting and excellent thing. No geocacher would disagree that more robust and accurate signals is good for GPS use but I do wonder whether it will aid in finding caches. Coordinates taken under the less accurate system won’t be any more correct under the new arrangement of satellites. There is such a variation in GPSr coordinates that I’m not sure it matters anyway.

The 50th Space Wing is in the middle of maneuvering six GPS satellites into more favorable positions. The two-phase operation, called “Expandable-24”  is halfway to completion.

Phase one began on January 13, almost exactly one year ago. The 2nd Space Operations Squadron, the Wing unit that controls GPS, began maneuvers on three selected satellites: SVN 24, SVN26 and SVN 49. One took 351 days to nudge into place. The third satellite completed repositioning on January 18, 2011.

That’s a long time to nudge something into place! It reminds me of the Austin Powers scene with the steam roller running over the minion.

Phase two of Expandable-24 began in August 2010 and is expected to be finished next June. Another three Three GPS satellites will be repositioned during the second phase.

The current GPS constellation has six more satellites in working order than the 24 it needs to make sure the system is fully operational 95 percent of the time. Before Expandable-24, the constellation geometry did not maximize the use of the extra satellites.

Make sure it is operational 95 percent of the time? Does that mean 5% of the time it is not operational or with the six extra they are operational more than 95% of the time? Or do they now cover more than 95% of the planet. Very confusing.

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  1. Tweets that mention GPS Satellites Moved for More Robust, Accurate Signals | Its Not About The Numbers -- Topsy.com

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