[time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

gkk gb modjklist at comcast.net
Fri Feb 10 19:35:45 EST 2017

Hello experts, I need a Rubidium frequency reference for my company, and wonder if I also need to GPS discipline it.

I characterize crystal-based OCXOs for ADEV, MTIE, and TDEV, and my longest measurement time is 100,000 seconds (28 hours). 

I'm looking at this graph from SRS for PRS10,


and thinking that as long as I calibrate a Rubidium source annually, there's no need for a GPS (since it only appears to degrade stability). Is this true in general, or is the graph misleading me because it may be true here, but not always.

So my question, is a GPS necessary to discipline a Rubidium standard to characterize the best crystal oscillators for stability, or can I do without it (and just calibrate the Rubidium annually to maintain accuracy) and actually get better stability?

How many seconds out is a GPS generally needed to improve accuracy from a Rubidium standard?

More information about the time-nuts mailing list