Hi

Well, the interesting point about Glonass timing is that it is independent of the
GPS empire. Galileo is another independent time source. Running a GPSDO
linked to each one would let you inter-compare the time from each of them.
Indeed I would guess that Galileo would do pretty well. Reports to date on
Glonass have not been encouraging. It still might be interesting to do. Once
Furuno releases the Galileo firmware, one of the Opus 7 based devices should
be able to run each of them. uBlox or some of the others would also do the
same thing.

Bob

On 2/16/2018 11:31 AM, Stewart Cobb wrote:

...

Look out for the shipping charge.

Hi

A full blown choke ring antenna is a pretty big heavy gizmo. That said,
yes indeed, some shipping charges are insane.

Bob

Yo Bob!

On Fri, 16 Feb 2018 13:47:24 -0500
Bob kb8tq kb8tq@n1k.org wrote:

I have been testing position accuracy lately on a self contained u-blox
8 with built-in antenna supposedly GLONASS capable.  I write a Python
script to selectively enable GLONASS and GALILEO over GPS.

All figures below are rough averages.

Typically, with one particular GPS, in one particular spot, it gives a
CEP(50) of 10 feet.

Enable GLONASS and that worsens to 24 feet.  After about a minute the
u-blox rejects all the GLONASS, that have good SNR, and the CEP(50)
drops back to normal.

Enable GALILEO and CEP(50) improves to 6 feet.  And stays that way.

So be sure to enable GALILEO in your GPS and disable GLONASS.

Also note: the passband of GALILEO is technically the same as GPS, but
has more energy at the edges.  Some GPS antennas cut it a little close
and hurt GALILEO performance.

RGDS
GARY

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com  Tel:+1 541 382 8588

    Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin

Hi

Part of the issue with Glonass is the accuracy of the datum. It can be used
for navigation and timing. It’s best to use it stand alone. Survey a location
that is specific to it’s datum and then lock the module into timing mode. Don’t
try to run with a GPS survey as your location.

All that said, still not encouraging.

Bob

On 2/16/18 10:47 AM, Bob kb8tq wrote:

However, if you're going to post process data using something like
Gipsy-X, they have "better estimates" of the time base for all the
systems, so you can get a combination. I suppose when you process you
tell it which one is your favorite base, and it adjusts to that.

Hi,

A complicating factor with GLONASS is the frequency separation of the
satellites which causes several aspects of calibration issues.

I know they have changed operational aspects which have reduced
uncertainty significantly. This is also something that have been worked
at with the GPS system continuously.

It's a bowl of mixed issues.

However, the more systems and the more bands we use, the better we get
at finding discrepancies and mitigate them. The "all" system and
frequencies is however still very expensive.

Cheers,
Magnus

On 02/16/2018 07:47 PM, Bob kb8tq wrote: