[LEAPSECS] Crunching Bulletin B numbers (POSIX time)

[Tim Shepard]

> Having a known list of leap seconds let one recover TAI time from a cold 

> GPS receiver in a few seconds to a minute, rather than waiting ~20 

> minutes for the almanac to download.  Many systems have their internal 


I thought GPS time had a constant offset from TAI of 19 seconds.  So
as soon as you have a GPS solution, you can find TAI.  No table of
leap seconds needed to accomplish that, as far as I know.


> clocks in TAI, but also have requirements to report time in UTC to 

> users.  Such a table would ensure these systems could come back online 

> quickly without having to pay the 20 minute penalty.  While the system 

> may have already been down a little while when the swap is made, an 

> extra 20 minutes can kill reliability targets for the system.


Hmm... maybe you could eliminate the need to report UTC time.  Or
have it report UTC time but have a flashing "aproximate" or
"estimate" indicator next to the display which flashes for the
first 20 minutes or so until it has received a complete copy of the
almanac.


			-Tim Shepard
			 shep at alum.mit.edu