|There are now at least six new Block IIR space vehicles in the GPS constellation. Five were made active in a relatively short span of 13 months from early 2000 through 2001. The oldest now has a track record of over 5 years of quality performance. An additional 14 have been built for launch over the next 5 years. Has navigation accuracy been any better as a result? What will it be like with the rest of the IIRs available? Have there been as many outages? Examination of the constellation performance with the Block IIRs added to date shows both increased navigation accuracy and increased availability of a healthy signal. This paper analyzes this improved performance in detail. It also examines the expected trend toward even greater accuracy and availability in the future as more IIRs become the backbone of the constellation. Finally, the new Block IIR modernization features are highlighted.
|NAVIGATION: Journal of the Institute of Navigation, Volume 50, Number 4
|219 - 234
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