Empathy List Archives

KL

Keith Loiselle

Thu, Nov 30, 2017 7:35 PM

Hello everyone,

I have heard reports of Trimble Mini-T timing glitches with offsets of 1ms
lasting for about 30 seconds several times during the past week. Some of
the dates and times reported are at various locations include:

23/11/2017, approx 11:00 UTC

29/11/2017, approx 11:00 UTC

30/11/2017, approx 12:00 UTC

We have not observed glitches with any of the equipment we have running,
but we have not had any Trimble units running during the past week. Has
anyone else observed similar glitches recently with Trimble or other GPS
equipment?

Thanks,

Keith

Hello everyone, I have heard reports of Trimble Mini-T timing glitches with offsets of 1ms lasting for about 30 seconds several times during the past week. Some of the dates and times reported are at various locations include: 23/11/2017, approx 11:00 UTC 29/11/2017, approx 11:00 UTC 30/11/2017, approx 12:00 UTC We have not observed glitches with any of the equipment we have running, but we have not had any Trimble units running during the past week. Has anyone else observed similar glitches recently with Trimble or other GPS equipment? Thanks, Keith

TS

Tim Shoppa

Thu, Nov 30, 2017 8:01 PM

Historical: Ancient (as in Trimble SVeeSix - 20 or more years ago) Trimble
GPS units would have their PPS timing output offset by several milliseconds
when they lost a sufficient number of satellites to maintain a 4D solution.

The PPS offset would jump back and forth by a large step (I recall six
milliseconds) when tracking was borderline.

I do not expect anything modern to have problems like this.

Tim N3QE

On Thu, Nov 30, 2017 at 2:35 PM, Keith Loiselle keith.loiselle@gmail.com
wrote:

Hello everyone,

I have heard reports of Trimble Mini-T timing glitches with offsets of 1ms
lasting for about 30 seconds several times during the past week. Some of
the dates and times reported are at various locations include:

23/11/2017, approx 11:00 UTC

29/11/2017, approx 11:00 UTC

30/11/2017, approx 12:00 UTC

We have not observed glitches with any of the equipment we have running,
but we have not had any Trimble units running during the past week. Has
anyone else observed similar glitches recently with Trimble or other GPS
equipment?

Thanks,

Keith

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mailman/listinfo/time-nuts
and follow the instructions there.

Historical: Ancient (as in Trimble SVeeSix - 20 or more years ago) Trimble GPS units would have their PPS timing output offset by several milliseconds when they lost a sufficient number of satellites to maintain a 4D solution. The PPS offset would jump back and forth by a large step (I recall six milliseconds) when tracking was borderline. I do not expect anything modern to have problems like this. Tim N3QE On Thu, Nov 30, 2017 at 2:35 PM, Keith Loiselle <keith.loiselle@gmail.com> wrote: > Hello everyone, > > I have heard reports of Trimble Mini-T timing glitches with offsets of 1ms > lasting for about 30 seconds several times during the past week. Some of > the dates and times reported are at various locations include: > > 23/11/2017, approx 11:00 UTC > > 29/11/2017, approx 11:00 UTC > > 30/11/2017, approx 12:00 UTC > > We have not observed glitches with any of the equipment we have running, > but we have not had any Trimble units running during the past week. Has > anyone else observed similar glitches recently with Trimble or other GPS > equipment? > > Thanks, > > Keith > _______________________________________________ > 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. >

BK

Bob kb8tq

Thu, Nov 30, 2017 8:27 PM

Hi

GPS extracts time and location by locking on to various codes in the transmissions.
One of them happens to run at about a 1 KHz clock rate. A slip on that part of the
process gives you a (modulo) 1 ms clock jump. Certain types of interference may
“help” the receiver make these sorts of mistakes.

Bob

On Nov 30, 2017, at 2:35 PM, Keith Loiselle keith.loiselle@gmail.com wrote:

Hello everyone,

I have heard reports of Trimble Mini-T timing glitches with offsets of 1ms
lasting for about 30 seconds several times during the past week. Some of
the dates and times reported are at various locations include:

23/11/2017, approx 11:00 UTC

29/11/2017, approx 11:00 UTC

30/11/2017, approx 12:00 UTC

We have not observed glitches with any of the equipment we have running,
but we have not had any Trimble units running during the past week. Has
anyone else observed similar glitches recently with Trimble or other GPS
equipment?

Thanks,

Keith

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.

Hi GPS extracts time and location by locking on to various codes in the transmissions. One of them happens to run at about a 1 KHz clock rate. A slip on that part of the process gives you a (modulo) 1 ms clock jump. Certain types of interference may “help” the receiver make these sorts of mistakes. Bob > On Nov 30, 2017, at 2:35 PM, Keith Loiselle <keith.loiselle@gmail.com> wrote: > > Hello everyone, > > I have heard reports of Trimble Mini-T timing glitches with offsets of 1ms > lasting for about 30 seconds several times during the past week. Some of > the dates and times reported are at various locations include: > > 23/11/2017, approx 11:00 UTC > > 29/11/2017, approx 11:00 UTC > > 30/11/2017, approx 12:00 UTC > > We have not observed glitches with any of the equipment we have running, > but we have not had any Trimble units running during the past week. Has > anyone else observed similar glitches recently with Trimble or other GPS > equipment? > > Thanks, > > Keith > _______________________________________________ > 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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Trimble Mini-T Timing Glitches