[time-nuts] GPS backup for the stationary time and frequencyuser

[Mark J. Blair]

On Oct 8, 2010, at 10:44 AM, J. Forster wrote:
> KISS. This seems like a lot of work for not particularily good results.
> Among other things, you have no closure so no measure of how good your
> measuremwent is.

Single-satellite timing mode is already commonly implemented in timing receivers; there's no work to be done other than turning it on. Closure is only lacking if all of the USAF ground stations are taken out such that the ephemeris and health information can no longer be updated on any intact birds; otherwise you know where every existing bird is at any instant in time, and each bird indicates whether it should be trusted.

Bottom line: If there's still one intact bird and one intact ground station to control it, you can get accurate time and frequency whenever it's visible (assuming no local jamming/spoofing) if you've already surveyed your position, using off-the-shelf hardware like a TBolt.

-- 
Mark J. Blair, NF6X <nf6x at nf6x.net>
Web page: http://www.nf6x.net/
GnuPG public key available from my web page.