[time-nuts] Russian GPSDO

SAIDJACK at aol.com SAIDJACK at aol.com
Wed Oct 19 18:20:48 UTC 2011

Hi Tom,
>I  am very eager to see lab reports of low-cost combined
>GPS+GLONASS  receivers. I bet Said has good info on
>the  u-blox 4T vs. 5T vs. 6T but now that he's selling to us
>instead  of sharing with us, you've noticed how quiet he
>is  about all this.
Sorry,  haven't posted as much info as I used to some time ago, I got 
burned by a  jealous competitor going after one of our customers and feeding  
them nonsense about us. Some folks will desperately use any  information they 
can to try to make themselves look better than they are..  And our baby is 
taking all of my spare time now :)
I  can safely say that the 6T works much better than 5T, much faster lock 
(~35s  versus ~50s typically), significantly lower power consumption, higher  
sensitivity (a couple of dB), and some other intricate electrical 
advantages  that I cannot detail unfortunately. Timing stability has not improved 
that much,  the 5T is already quite excellent. A larger timing stability 
difference is  visible in the non-timing, mobile receivers for 5S versus 6S for 
example.  We support both versions moving forward (for legacy customers who do 
not  want to change over). Using a timing receiver improves stability quite 
 remarkably in static conditions, on good CSAC boards we see standard 
deviation  as reported by GPSCon go down from say 11ns to less than 4ns when 
enabling  Position Hold mode and with the antenna below foliage.
Motorola  M12M and M12+ are still the king of the hill unfortunately, even 
with 6T being  available. But uBlox works wonderfully well in moving 
platforms when configured  properly. They even support both Carrier Phase AND 
Doppler tracking, depending  on the dynamic mode settings, which in our software 
can be selected  automatically, or through simple SCPI commands. WAAS/EGNOS 
improves horizontal  accuracy to typically better than 0.8 meters typically, 
even while moving in an  airplane. Better horizontal accuracy means better 
timing accuracy of course, as  one is essentially the reciprocal of the 
Will  report on the Glonass enabled parts when we have that information. 
It's too  early for now.
>(Hey,  no harm meant, but don't forget
>where  you came from).
Lastly,  I can happily say that we are actively working on solutions that 
will appeal to  Time Nuts, Hams, and others who are concerned about low cost 
but want great  performance. More on this later this year..

More information about the time-nuts mailing list