[time-nuts] GPS SDR (was: FE-.5680A trimming resolution)

Attila Kinali attila at kinali.ch
Wed Feb 1 20:01:45 UTC 2012

On Wed, 1 Feb 2012 11:03:19 -0800
Chris Albertson <albertson.chris at gmail.com> wrote:

> On Wed, Feb 1, 2012 at 10:18 AM, Attila Kinali <attila at kinali.ch> wrote:
> > That said. I've contacted u-blox, but got a number that is way out of
> > what i've expected (approx 120CHF). I'm currently trying to get a lower
> > price.
> What is it these u-blox device can do that a cheaper Motorola Oncore
> can't?   Depending on the version the Oncore has for 50 to 5 nS
> one-sigma error on the timing pulses and can do either 1PPS or 100PPS.
>   Single unit prices are from $18 to $60 very good documentation is
> available.

The Timing Appnote [1] says, that the 1PPS error's sigma is 6.7ns, before
sawtooth correction and 3.0ns after.
> If the u-blox was somehow much better than a Trimble thunderbolt or

I dont have the numbers, but I doubt that a LEA-6T can beat a thunderbolt.

> Motorola Oncore MT12T I'd buy one even at the above price.   But
> really these older GPSs are already at the single digtit of
> nanoseconds level and I don't see room for improvement except....
> If the L2 band is also used.   This is the way to get order of
> magnitude improments

They are not dual band receivers. Yes, that would be really an improvement..

But i'm not convincing you to buy a LEA-6T. Nor do i think that it's
a must have for anyone. Heck, you can get a complete thunderbolt with
supply and antenna for 200USD on ebay. No LEA-6T based system will ever
get that cheap. But there is not much way to tinker with a thunderbolt.
You cannot play with its design. If you build a system from scratch,
you can. 

				Attila Kinali

[1] https://www.u-blox.com/images/downloads/Product_Docs/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
Why does it take years to find the answers to
the questions one should have asked long ago?

More information about the time-nuts mailing list