[time-nuts] NIST

David I. Emery die at dieconsulting.com
Sat Sep 1 14:36:55 EDT 2018


On Fri, Aug 31, 2018 at 10:23:14PM -0700, Hal Murray wrote:
> 
> plaws0 at gmail.com said:
> > Which satellites?  Most are here:  https://celestrak.com  Tracking programs
> > are abundant. 
> 
> I was thinking of geo-sync, but if position info is widely available then I 
> guess I should be interested in any satellites that provide good time.  (maybe 
> an are likely to continue providing good time after some nasty event)


	I hate to intrude into such an august group of experts, but as a
practical matter what sort of real world timing accuracy could one
really expect from using just ONE of the WAAS birds and a dedicated L
band dish ?

	I do understand the WAAS satellites do transmit a L1 carrier
with a full and correct GPS signal and ephemerides for the WAAS
satellite in addition to their other correction information, so I
presume one could use single satellite timing mode with a variety of GPS
timing receivers that support this... given of course a suitably
accurately surveyed ground position of the dish...

	There are obviously SOME degree of ionospheric corrections
possible from the WAAS data... how much good do they do in practice
for this special case of single satellite timing ?

-- 
  Dave Emery N1PRE/AE, die at dieconsulting.com  DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."




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