Re: [time-nuts] Trimble SMT 360

[Björn]

Why would the receiver swap between two solutions. One measurement is typically 
used to compute the time delta between the glonass and gps time.

--
     Björn

 Originalmeddelande Från: Bob Camp 
<kb...@n1k.org> Datum:2016-04-20  05:26  (GMT+07:00) 
Till: Discussion of precise time and frequency measurement 
<time-nuts@febo.com> Rubrik: Re: [time-nuts] Trimble SMT 360 

Hi

Actually there is one other possibility: 

If you have more than one “system” enabled *and* it’s doing “all in view” *and* 
it’s applying that 
to the timing *and* the population in view changes significantly … (whew !) 

As the solution pops between GPS and Glonass, you will get a time shift. Since 
it’s a “which one
is right?” sort of thing … Trimble probably does not want to get into the 
debate. They would love
to sell stuff to everybody.

Bob


> On Apr 19, 2016, at 3:32 PM, Logan Cummings <logan.cummi...@gmail.com> wrote:
> 
> Hi Michael, Bob,
> 
> I had been very curious about this myself - the new ICM SMT 360
> modules at first glance seem like a great deal - < $50 and 10MHz TCXO
> disciplining built right in.
> 
> I came across this paper which compares the older (GPS-only) ICM SMT
> to a LEA-6T - the Trimble fares poorly in their testing.  The graphs don't
> show an issue quite like yours Michael, so I'd be curious about the line of
> questioning Bob brings up, how many satellites are being used by the
> receiver - say in GPS-only mode?
> 
> http://www.imeko.org/publications/tc10-2013/IMEKO-TC10-2013-028.pdf
> 
>Does anyone else have comparative experience with the new SMT modules
> from Trimble? RES or ICM?
> 
> Thanks,
> -Logan
> 
> On Tue, Apr 19, 2016 at 4:01 AM, Bob Camp <kb...@n1k.org> wrote:
> 
>> Hi
>> 
>> The two plots shown appear to be identical. If they are actually two
>> different
>> runs, the problem repeats very closely.
>> 
>> If the GPS is not in position hold *and* the antenna is less than ideal -
>> That’s
>> the sort of thing you may see. Essentially it’s got two locations it
>> “thinks” are
>> correct. Another possibility is a position hold situation with a very low
>> satellite count.
>> As a single observed satellite goes in and out of multi path, the solution
>> goes all over the place.
>> Again, you need a challenged antenna for this to happen. Pretty much all
>> of this
>> would be apparent from the normal messages out of the part.
>> 
>> Bob
>> 
>> 
>> 
>>> On Apr 18, 2016, at 10:13 PM, Michael Wouters <michaeljwout...@gmail.com>
>> wrote:
>>> 
>>> Does anyone have  experience with the Trimble SMT 360 ?
>>> 
>>> I bought some of these four or five months after they were released.
>> During
>>> testing, the 1 pps output evidenced a problem, as shown in the attached
>>> plot (the 1 pps is being measured against a Cs  beam standard), which is
>>> not sawtooth-corrected. While there are longish periods of nominal
>>> operation, the receiver seems to hop between two solutions.  This
>> behaviour
>>> is well out of specification.
>>> 
>>> When I contacted Trimble support, they said that the firmware in the
>>> receivers was very early, and replaced the receivers. However, the
>> problem
>>> was still evident with the new firmware. Trimble did not respond to
>> further
>>> emails.
>>> 
>>> I tried many things to isolate the problem, including restricting the
>>> receiver to GPS-only but I was unable to make an improvement.
>>> 
>>> I would like to know if anyone else is operating an SMT 360 and if they
>>> have seen any similar behaviour.
>>> 
>>> Cheers[image: Inline image 2]
>>> Michael[image: Inline image 1]
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
> ___
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Re: [time-nuts] Trimble SMT 360

[Michael Wouters]

Dear Bob

( I shouldn't write email while walking around doing the housework!)

The possibility of other constellations causing a problem was one of the
things I checked, running it in GPS only mode. No improvement.

Cheers
Michael

On Wednesday, 20 April 2016, Bob Camp  wrote:

> Hi
>
> Actually there is one other possibility:
>
> If you have more than one “system” enabled *and* it’s doing “all in view”
> *and* it’s applying that
> to the timing *and* the population in view changes significantly … (whew !)
>
> As the solution pops between GPS and Glonass, you will get a time shift.
> Since it’s a “which one
> is right?” sort of thing … Trimble probably does not want to get into the
> debate. They would love
> to sell stuff to everybody.
>
> Bob
>
>
> > On Apr 19, 2016, at 3:32 PM, Logan Cummings  > wrote:
> >
> > Hi Michael, Bob,
> >
> > I had been very curious about this myself - the new ICM SMT 360
> > modules at first glance seem like a great deal - < $50 and 10MHz TCXO
> > disciplining built right in.
> >
> > I came across this paper which compares the older (GPS-only) ICM SMT
> > to a LEA-6T - the Trimble fares poorly in their testing.  The graphs
> don't
> > show an issue quite like yours Michael, so I'd be curious about the line
> of
> > questioning Bob brings up, how many satellites are being used by the
> > receiver - say in GPS-only mode?
> >
> > http://www.imeko.org/publications/tc10-2013/IMEKO-TC10-2013-028.pdf
> >
> >Does anyone else have comparative experience with the new SMT modules
> > from Trimble? RES or ICM?
> >
> > Thanks,
> > -Logan
> >
> > On Tue, Apr 19, 2016 at 4:01 AM, Bob Camp >
> wrote:
> >
> >> Hi
> >>
> >> The two plots shown appear to be identical. If they are actually two
> >> different
> >> runs, the problem repeats very closely.
> >>
> >> If the GPS is not in position hold *and* the antenna is less than ideal
> -
> >> That’s
> >> the sort of thing you may see. Essentially it’s got two locations it
> >> “thinks” are
> >> correct. Another possibility is a position hold situation with a very
> low
> >> satellite count.
> >> As a single observed satellite goes in and out of multi path, the
> solution
> >> goes all over the place.
> >> Again, you need a challenged antenna for this to happen. Pretty much all
> >> of this
> >> would be apparent from the normal messages out of the part.
> >>
> >> Bob
> >>
> >>
> >>
> >>> On Apr 18, 2016, at 10:13 PM, Michael Wouters <
> michaeljwout...@gmail.com >
> >> wrote:
> >>>
> >>> Does anyone have  experience with the Trimble SMT 360 ?
> >>>
> >>> I bought some of these four or five months after they were released.
> >> During
> >>> testing, the 1 pps output evidenced a problem, as shown in the attached
> >>> plot (the 1 pps is being measured against a Cs  beam standard), which
> is
> >>> not sawtooth-corrected. While there are longish periods of nominal
> >>> operation, the receiver seems to hop between two solutions.  This
> >> behaviour
> >>> is well out of specification.
> >>>
> >>> When I contacted Trimble support, they said that the firmware in the
> >>> receivers was very early, and replaced the receivers. However, the
> >> problem
> >>> was still evident with the new firmware. Trimble did not respond to
> >> further
> >>> emails.
> >>>
> >>> I tried many things to isolate the problem, including restricting the
> >>> receiver to GPS-only but I was unable to make an improvement.
> >>>
> >>> I would like to know if anyone else is operating an SMT 360 and if they
> >>> have seen any similar behaviour.
> >>>
> >>> Cheers[image: Inline image 2]
> >>> Michael[image: Inline image 1]
> >>> ___
> >>> time-nuts mailing list -- time-nuts@febo.com 
> >>> To unsubscribe, go to
> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>> and follow the instructions there.
> >>
> >> ___
> >> time-nuts mailing list -- time-nuts@febo.com 
> >> To unsubscribe, go to
> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> and follow the instructions there.
> >>
> > ___
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> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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Re: [time-nuts] Trimble SMT 360

[Michael Wouters]

Dear Bob,

Sorry, the two plots are identical; it was a drag and drop fumble.

I should have given more detail - "tried many things" included running the
receiver in position hold ( which is the default ) and free run. The
receiver was being logged during operation and always claimed 5 to 10 SVs.
The antenna is roof-mounted with an excellent view of the sky. I tried
multiple antennas just in case, added a bit of gain, tried multiple SMT
360s, compared with other receivers in the lab ( Resolution T, Javad,
Septentrio, VP Oncore) ...

Another thing I didn't mention was that I tried it on a GPS simulator,
except with a position in the Northern hemisphere ( I'm in the South ) and
it worked fine for 12 hours. I wasn't sure what to make of this but decided
to stop spending my time on this because it was really Somebody Else's
Problem to solve.

In the end, I decided to use another receiver for my application ( GPS
common view, for which we'd been using the Resolution T previously ) but
now that that's almost done, I thought I'd have another look at the the SMT
360 problems.

Cheers
Michael

On Tuesday, 19 April 2016, Bob Camp  wrote:

> Hi
>
> The two plots shown appear to be identical. If they are actually two
> different
> runs, the problem repeats very closely.
>
> If the GPS is not in position hold *and* the antenna is less than ideal -
> That’s
> the sort of thing you may see. Essentially it’s got two locations it
> “thinks” are
> correct. Another possibility is a position hold situation with a very low
> satellite count.
> As a single observed satellite goes in and out of multi path, the solution
> goes all over the place.
> Again, you need a challenged antenna for this to happen. Pretty much all
> of this
> would be apparent from the normal messages out of the part.
>
> Bob
>
>
>
> > On Apr 18, 2016, at 10:13 PM, Michael Wouters  > wrote:
> >
> > Does anyone have  experience with the Trimble SMT 360 ?
> >
> > I bought some of these four or five months after they were released.
> During
> > testing, the 1 pps output evidenced a problem, as shown in the attached
> > plot (the 1 pps is being measured against a Cs  beam standard), which is
> > not sawtooth-corrected. While there are longish periods of nominal
> > operation, the receiver seems to hop between two solutions.  This
> behaviour
> > is well out of specification.
> >
> > When I contacted Trimble support, they said that the firmware in the
> > receivers was very early, and replaced the receivers. However, the
> problem
> > was still evident with the new firmware. Trimble did not respond to
> further
> > emails.
> >
> > I tried many things to isolate the problem, including restricting the
> > receiver to GPS-only but I was unable to make an improvement.
> >
> > I would like to know if anyone else is operating an SMT 360 and if they
> > have seen any similar behaviour.
> >
> > Cheers[image: Inline image 2]
> > Michael[image: Inline image 1]
> > ___
> > time-nuts mailing list -- time-nuts@febo.com 
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
> ___
> time-nuts mailing list -- time-nuts@febo.com 
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Trimble SMT 360

[Bob Camp]

Hi

Actually there is one other possibility: 

If you have more than one “system” enabled *and* it’s doing “all in view” *and* 
it’s applying that 
to the timing *and* the population in view changes significantly … (whew !) 

As the solution pops between GPS and Glonass, you will get a time shift. Since 
it’s a “which one
is right?” sort of thing … Trimble probably does not want to get into the 
debate. They would love
to sell stuff to everybody.

Bob


> On Apr 19, 2016, at 3:32 PM, Logan Cummings  wrote:
> 
> Hi Michael, Bob,
> 
> I had been very curious about this myself - the new ICM SMT 360
> modules at first glance seem like a great deal - < $50 and 10MHz TCXO
> disciplining built right in.
> 
> I came across this paper which compares the older (GPS-only) ICM SMT
> to a LEA-6T - the Trimble fares poorly in their testing.  The graphs don't
> show an issue quite like yours Michael, so I'd be curious about the line of
> questioning Bob brings up, how many satellites are being used by the
> receiver - say in GPS-only mode?
> 
> http://www.imeko.org/publications/tc10-2013/IMEKO-TC10-2013-028.pdf
> 
>Does anyone else have comparative experience with the new SMT modules
> from Trimble? RES or ICM?
> 
> Thanks,
> -Logan
> 
> On Tue, Apr 19, 2016 at 4:01 AM, Bob Camp  wrote:
> 
>> Hi
>> 
>> The two plots shown appear to be identical. If they are actually two
>> different
>> runs, the problem repeats very closely.
>> 
>> If the GPS is not in position hold *and* the antenna is less than ideal -
>> That’s
>> the sort of thing you may see. Essentially it’s got two locations it
>> “thinks” are
>> correct. Another possibility is a position hold situation with a very low
>> satellite count.
>> As a single observed satellite goes in and out of multi path, the solution
>> goes all over the place.
>> Again, you need a challenged antenna for this to happen. Pretty much all
>> of this
>> would be apparent from the normal messages out of the part.
>> 
>> Bob
>> 
>> 
>> 
>>> On Apr 18, 2016, at 10:13 PM, Michael Wouters 
>> wrote:
>>> 
>>> Does anyone have  experience with the Trimble SMT 360 ?
>>> 
>>> I bought some of these four or five months after they were released.
>> During
>>> testing, the 1 pps output evidenced a problem, as shown in the attached
>>> plot (the 1 pps is being measured against a Cs  beam standard), which is
>>> not sawtooth-corrected. While there are longish periods of nominal
>>> operation, the receiver seems to hop between two solutions.  This
>> behaviour
>>> is well out of specification.
>>> 
>>> When I contacted Trimble support, they said that the firmware in the
>>> receivers was very early, and replaced the receivers. However, the
>> problem
>>> was still evident with the new firmware. Trimble did not respond to
>> further
>>> emails.
>>> 
>>> I tried many things to isolate the problem, including restricting the
>>> receiver to GPS-only but I was unable to make an improvement.
>>> 
>>> I would like to know if anyone else is operating an SMT 360 and if they
>>> have seen any similar behaviour.
>>> 
>>> Cheers[image: Inline image 2]
>>> Michael[image: Inline image 1]
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Re: [time-nuts] Trimble SMT 360

[Logan Cummings]

Hi Michael, Bob,

 I had been very curious about this myself - the new ICM SMT 360
modules at first glance seem like a great deal - < $50 and 10MHz TCXO
disciplining built right in.

 I came across this paper which compares the older (GPS-only) ICM SMT
to a LEA-6T - the Trimble fares poorly in their testing.  The graphs don't
show an issue quite like yours Michael, so I'd be curious about the line of
questioning Bob brings up, how many satellites are being used by the
receiver - say in GPS-only mode?

http://www.imeko.org/publications/tc10-2013/IMEKO-TC10-2013-028.pdf

Does anyone else have comparative experience with the new SMT modules
from Trimble? RES or ICM?

Thanks,
-Logan

On Tue, Apr 19, 2016 at 4:01 AM, Bob Camp  wrote:

> Hi
>
> The two plots shown appear to be identical. If they are actually two
> different
> runs, the problem repeats very closely.
>
> If the GPS is not in position hold *and* the antenna is less than ideal -
> That’s
> the sort of thing you may see. Essentially it’s got two locations it
> “thinks” are
> correct. Another possibility is a position hold situation with a very low
> satellite count.
> As a single observed satellite goes in and out of multi path, the solution
> goes all over the place.
> Again, you need a challenged antenna for this to happen. Pretty much all
> of this
> would be apparent from the normal messages out of the part.
>
> Bob
>
>
>
> > On Apr 18, 2016, at 10:13 PM, Michael Wouters 
> wrote:
> >
> > Does anyone have  experience with the Trimble SMT 360 ?
> >
> > I bought some of these four or five months after they were released.
> During
> > testing, the 1 pps output evidenced a problem, as shown in the attached
> > plot (the 1 pps is being measured against a Cs  beam standard), which is
> > not sawtooth-corrected. While there are longish periods of nominal
> > operation, the receiver seems to hop between two solutions.  This
> behaviour
> > is well out of specification.
> >
> > When I contacted Trimble support, they said that the firmware in the
> > receivers was very early, and replaced the receivers. However, the
> problem
> > was still evident with the new firmware. Trimble did not respond to
> further
> > emails.
> >
> > I tried many things to isolate the problem, including restricting the
> > receiver to GPS-only but I was unable to make an improvement.
> >
> > I would like to know if anyone else is operating an SMT 360 and if they
> > have seen any similar behaviour.
> >
> > Cheers[image: Inline image 2]
> > Michael[image: Inline image 1]
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Trimble SMT 360

[Bob Camp]

Hi

The two plots shown appear to be identical. If they are actually two different 
runs, the problem repeats very closely. 

If the GPS is not in position hold *and* the antenna is less than ideal - 
That’s 
the sort of thing you may see. Essentially it’s got two locations it “thinks” 
are 
correct. Another possibility is a position hold situation with a very low 
satellite count. 
As a single observed satellite goes in and out of multi path, the solution goes 
all over the place. 
Again, you need a challenged antenna for this to happen. Pretty much all of 
this 
would be apparent from the normal messages out of the part.

Bob



> On Apr 18, 2016, at 10:13 PM, Michael Wouters  
> wrote:
> 
> Does anyone have  experience with the Trimble SMT 360 ?
> 
> I bought some of these four or five months after they were released. During
> testing, the 1 pps output evidenced a problem, as shown in the attached
> plot (the 1 pps is being measured against a Cs  beam standard), which is
> not sawtooth-corrected. While there are longish periods of nominal
> operation, the receiver seems to hop between two solutions.  This behaviour
> is well out of specification.
> 
> When I contacted Trimble support, they said that the firmware in the
> receivers was very early, and replaced the receivers. However, the problem
> was still evident with the new firmware. Trimble did not respond to further
> emails.
> 
> I tried many things to isolate the problem, including restricting the
> receiver to GPS-only but I was unable to make an improvement.
> 
> I would like to know if anyone else is operating an SMT 360 and if they
> have seen any similar behaviour.
> 
> Cheers[image: Inline image 2]
> Michael[image: Inline image 1]
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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[time-nuts] Trimble SMT 360

[Michael Wouters]

Does anyone have  experience with the Trimble SMT 360 ?

I bought some of these four or five months after they were released. During
testing, the 1 pps output evidenced a problem, as shown in the attached
plot (the 1 pps is being measured against a Cs  beam standard), which is
not sawtooth-corrected. While there are longish periods of nominal
operation, the receiver seems to hop between two solutions.  This behaviour
is well out of specification.

When I contacted Trimble support, they said that the firmware in the
receivers was very early, and replaced the receivers. However, the problem
was still evident with the new firmware. Trimble did not respond to further
emails.

I tried many things to isolate the problem, including restricting the
receiver to GPS-only but I was unable to make an improvement.

I would like to know if anyone else is operating an SMT 360 and if they
have seen any similar behaviour.

Cheers[image: Inline image 2]
Michael[image: Inline image 1]
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