Carrier-Phase Anomalies Detected on SVN-48
May 17, 2010
By Brady O’Hanlon, Mark L. Psiaki, Paul M. Kintner Jr., and Steven P. Powell Anomalous behavior of the […]
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By Brady O’Hanlon, Mark L. Psiaki, Paul M. Kintner Jr., and Steven P. Powell Anomalous behavior of the […]
I didn’t plan it this way, but my coverage of GPS 24+3 turned out to be a three-part series, with this column being part three. One reason it turned into a three-part series is because I’m learning more about it along the way, but its mostly because details weren’t released all at once.
In the few years I’ve been writing this column, very few subjects have warranted back-to-back newsletter coverage. The new GPS 24+3 configuration is one of them. The reason I’ve continued with this discussion is because it will significantly affect your GPS operations, especially if you’re using RTK or DGPS.
The U.S. Air Force GPS Wing and 50th Space Wing have begun repositioning GPS satellites in space to fly what they call the 24+3 or Expandable 24 constellation plan. The initiative will take up to 24 months to fully implement. Benefits to users will be slowly realized during that time, as the number of GPS satellites in view will increase, potentially increasing GPS receiver accuracy. Plus: Penny-Wise, Pound-Foolish U.S. Coast Guard to Pull Loran Plug; Galileo Satellites Awarded to OHB; Compass at Three
Last week, the U.S. Air Force announced it is reconfiguring the GPS constellation. The Air Force is changing the constellation from a 21+3 configuration to a 24+3 configuration. The result will be more satellites in view, on average. This is great news for the GPS surveying and GIS mapping user. In my opinion, it was the only achievable short/medium-term solution to the GPS “brownout” problem that has plagued GPS surveying and mapping users for years, and has worsened in recent months.
The Russian space agency Roscosmos launched a venerable Proton rocket carrying three GLONASS-M satellites into orbit on December 14. […]
Four Galileo in-orbit validation (IOV) satellites scheduled to launch next year have already missed their first pad date.The […]
It appears that the GPS satellite constellation has a glass ceiling, so to speak. GPS was designed as a 24-satellite constellation, with four satellites in six orbital planes arranged to provide maximum observability around the globe. According to the government’s Space-Based Positioning, Navigation, and Timing website, “The U.S. government is committed to provide a minimum of 24 operational GPS satellites on orbit, 95 percent of the time. The U.S. Air Force launches additional satellites that function as active spares to accommodate periodic satellite maintenance downtime and assure the availability of at least 24 operating satellites. As of August 28, 2009, there were 35 satellites in the GPS constellation, with 30 set ‘healthy’ to users.”
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