I suspect this topic has been addressed but I did,nt find on this web site. In late 2005 another satellite with different frequency will be released. Our current devices will still work and do the standard tri-lateration using the 4 satellites in the primary cone. Canopy is a real problem in forest areas and this will be overcome. This update is anticipated to give us up to a 2cm positioning. I,ve advised new geocachers I know to buy a used or discounted gps and go for the new whizzer when it,s released. The article I read regarding this topic was in a recent Scientific American magazine. I suspect many of you know a lot more about this subject than I do . If I read this correctly we are in for some exciting technology. If my info is incorrect you won,t hurt my feelings by letting me know.