[LEAPSECS] GPS certified for navigation?

[Robert Seaman]

An article in the most recent Risks Digest:

	http://catless.ncl.ac.uk/Risks/26.17.html#subj11.1

contains this provocative statement in passing:

	"my GPS [...] warns me not to use it for navigation every time I turn it on"

What precisely is the status of GPS for actual purposes of navigation?  Obviously astronomy is deemed to be an activity of no economic utility whatsoever - it's so easy to write off 99.999999999% of the universe :-)  That leaves the entire case for emasculating UTC resting on the notion that GPS has obsoleted all prior navigation technologies.  This may be news to the GPS industry if they are including such disclaimers in their devices.

Rob