On Thu, Jun 3, 2010 at 7:29 UTC, "Rob" wrote:
> NMEA should not be trusted for time messages. The time in an
> NMEA message is the "time of fix", i.e. the time at which the last
> fix calculation was made in the receiver, and at which moment the
> position values in the message were valid. There
Hal Murray wrote:
>
>>Apparently their firmware is crap.
>>
>>But have you also seen this with bare GPS receivers?
>>Wrong time but indication of lock to GPS (2D or 3D).
>
> I've seen output from a Garmin GPS-18 that was off by a second.
>
> I don't have details. It's on my list to play with.
>
>
"Uwe Klein" wrote in message
news:7hmid7-sqs@klein-habertwedt.de...
[]
http://www8.garmin.com/support/pdf/NMEA_0183.pdf
http://www8.garmin.com/manuals/GarminMobile10forlaptops_PDAs_TechnicalSpecifications.pdf
nothing.
but:
http://www8.garmin.com/support/download_details.jsp?id=377
see vers
Terje,
The Spectracom WWVB (type 4) driver, among others, uses the qualitity
indicator provided in the timecode message to set the dispersion when read.
Dave
Terje Mathisen wrote:
David J Taylor wrote:
"Miroslav Lichvar" wrote in message
news:hu5osh$kc...@speranza.aioe.org...
[]
I coul
David J Taylor wrote:
"Miroslav Lichvar" wrote in message
news:hu5c32$p...@speranza.aioe.org...
On 2010-06-02, David J Taylor
wrote:
[]
.. including the popular GPS18 LVC. So it's better to have a driver
which
reads the serial output of the GPS to confirm lock.
GPS18(x) LVC supports
David J Taylor wrote:
"Miroslav Lichvar" wrote in message
news:hu5osh$kc...@speranza.aioe.org...
[]
I couldn't find a description either, but it seems to work as expected.
PPS is turned off when the sync is lost and turned on when a fix is
back. It works only when the fix status is changed, i.e
David J Taylor wrote:
> "Miroslav Lichvar" wrote in message
> news:hu5osh$kc...@speranza.aioe.org...
> []
>> I couldn't find a description either, but it seems to work as expected.
>> PPS is turned off when the sync is lost and turned on when a fix is
>> back. It works only when the fix status i
"Miroslav Lichvar" wrote in message
news:hu5osh$kc...@speranza.aioe.org...
[]
I couldn't find a description either, but it seems to work as expected.
PPS is turned off when the sync is lost and turned on when a fix is
back. It works only when the fix status is changed, i.e. the command
itself d
Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
> pc wrote:
>> The Motorola Oncore UT GPS receiver, which was designed as a precision
>> time source, has a T-RAIM (time receiver autonomous integrity
>> monitoring)
>> feature which, properly configured, switches off the PPS output if
>> the rece
On 2010-06-02, David J Taylor wrote:
>> GPS18(x) LVC supports a PPS auto off mode which can be enabled with
>> "$PGRMC1,2" command.
>
> Interesting, Miroslav. I was referring to this statement in section
> 4.4.1:
>
> "After the initial position fix has been calculated, the PPS sign
Rob wrote:
Terje Mathisen<"terje.mathisen at tmsw.no"> wrote:
Kalle Pokki wrote:
From my experience, hardware or well designed and tested software
going crazy (i.e. outputting completely invalid data) without any
safeguards noticing it usually requires quite bizarre double failures
in the sy
pc wrote:
The Motorola Oncore UT GPS receiver, which was designed as a precision
time source, has a T-RAIM (time receiver autonomous integrity
monitoring)
feature which, properly configured, switches off the PPS output if
the receiver loses lock.
Which is why my 3 core (+ 3 backup) NTP servers
"Miroslav Lichvar" wrote in message
news:hu5c32$p...@speranza.aioe.org...
On 2010-06-02, David J Taylor
wrote:
[]
.. including the popular GPS18 LVC. So it's better to have a driver
which
reads the serial output of the GPS to confirm lock.
GPS18(x) LVC supports a PPS auto off mode which c
Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
> Kalle Pokki wrote:
>>> From my experience, hardware or well designed and tested software
>> going crazy (i.e. outputting completely invalid data) without any
>> safeguards noticing it usually requires quite bizarre double failures
>> in the syst
Kalle Pokki wrote:
From my experience, hardware or well designed and tested software
going crazy (i.e. outputting completely invalid data) without any
safeguards noticing it usually requires quite bizarre double failures
in the system at the same time. Thinking this I sometimes wonder the
I ha
On 2010-06-02, David J Taylor wrote:
>>>The Motorola Oncore UT GPS receiver, which was designed as a precision
>>>time source, has a T-RAIM (time receiver autonomous integrity
>>>monitoring)
>>>feature which, properly configured, switches off the PPS output if
>>>the receiver loses lock.
>>
>> But
"Hal Murray" wrote in message
news:c8odnqf1so3ijjvrnz2dnuvz_jidn...@megapath.net...
In article
<884d589f-378f-4568-a641-003c6bea9...@d12g2000vbr.googlegroups.com>,
pc writes:
The Motorola Oncore UT GPS receiver, which was designed as a precision
time source, has a T-RAIM (time receiver autono
Hal Murray wrote:
> In article
> <884d589f-378f-4568-a641-003c6bea9...@d12g2000vbr.googlegroups.com>,
> pc writes:
>>The Motorola Oncore UT GPS receiver, which was designed as a precision
>>time source, has a T-RAIM (time receiver autonomous integrity
>>monitoring)
>>feature which, properly con
In article <884d589f-378f-4568-a641-003c6bea9...@d12g2000vbr.googlegroups.com>,
pc writes:
>The Motorola Oncore UT GPS receiver, which was designed as a precision
>time source, has a T-RAIM (time receiver autonomous integrity
>monitoring)
>feature which, properly configured, switches off the PPS
The Motorola Oncore UT GPS receiver, which was designed as a precision
time source, has a T-RAIM (time receiver autonomous integrity
monitoring)
feature which, properly configured, switches off the PPS output if
the receiver loses lock.
Paul
___
questio
unruh wrote:
>> That of course could happen, but the scenario requires some really
>> convenient failure in the GPS unit. If the GPS lock is lost, at least
>> the GPS units I have tested will indicate their clock is freewheeling.
>> The time is then discarded by gpsd as invalid and will not be fed
On 2010-06-01, Kalle Pokki wrote:
> On Tue, Jun 1, 2010 at 00:10, unruh wrote:
>
>>> If we assume there is a private subnet that has two GPS reference
>>> clocks to synchronize the rest of the machines, what would be the
>>> expected failure mode where one of the stratum 1 servers go crazy, and
>
unruh wrote:
> On 2010-06-01, Rob wrote:
>> unruh wrote:
If we assume there is a private subnet that has two GPS reference
clocks to synchronize the rest of the machines, what would be the
expected failure mode where one of the stratum 1 servers go crazy, and
having three GPS
On 2010-06-01, Rob wrote:
> unruh wrote:
>>> If we assume there is a private subnet that has two GPS reference
>>> clocks to synchronize the rest of the machines, what would be the
>>> expected failure mode where one of the stratum 1 servers go crazy, and
>>> having three GPS clocks actually make
On Tue, Jun 1, 2010 at 00:10, unruh wrote:
>> If we assume there is a private subnet that has two GPS reference
>> clocks to synchronize the rest of the machines, what would be the
>> expected failure mode where one of the stratum 1 servers go crazy, and
>> having three GPS clocks actually makes
On Mon, May 31, 2010 at 22:14, Richard B. Gilbert
wrote:
> The more common case is that a server fails due to something like a power
> outrage. When the power comes back, that server may be off by several
> seconds, or minutes. It may take ten to twelve hours before that server is
> fit to serv
unruh wrote:
>> If we assume there is a private subnet that has two GPS reference
>> clocks to synchronize the rest of the machines, what would be the
>> expected failure mode where one of the stratum 1 servers go crazy, and
>> having three GPS clocks actually makes a difference?
>
> The gps falls
On 2010-05-31, Kalle Pokki wrote:
> On Mon, May 31, 2010 at 06:42, unruh wrote:
>> Note, that this is one of the reasons why your customers should never
>> use 2 servers. You have no way to know which one is crazy. Use 3 or 5.
>> (4 can be as bad as 2 if two of the servers go nuts in exactly the
On 2010-05-31, Richard B. Gilbert wrote:
> unruh wrote:
>> On 2010-05-30, Richard B. Gilbert wrote:
>>> bombjack wrote:
Hi,
I am fairly new to the ntp arena, but have to learn fast as part of my
work is trying to fix ntp problems. Lately I had a customer that
complained that t
References: <4eea00b1-966a-4f39-a6cc-265ce959c...@s4g2000prh.googlegroups.com>
On 2010-05-31, Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
unruh wrote:
Note, that this is one of the reasons why your customers should never
use 2 servers. You have no way to know which one is crazy. Use
When we talk about "insane" or "broken" clocks, the context is
important. What we are really talking about is what we call a
"falseticker", that is, a clock that does not have the actual time in
the range of its offset plus or minus its dispersion. So, with that
definition the amount by which it is
David Woolley wrote:
Richard B. Gilbert wrote:
The more common case is that a server fails due to something like a
power outrage. When the power comes back, that server may be off by
several seconds, or minutes. It may take ten to twelve hours before
that server is fit to serve time to an
Richard B. Gilbert wrote:
The more common case is that a server fails due to something like a
power outrage. When the power comes back, that server may be off by
several seconds, or minutes. It may take ten to twelve hours before
that server is fit to serve time to any but the truly desper
Kalle Pokki wrote:
On Mon, May 31, 2010 at 06:42, unruh wrote:
Note, that this is one of the reasons why your customers should never
use 2 servers. You have no way to know which one is crazy. Use 3 or 5.
(4 can be as bad as 2 if two of the servers go nuts in exactly the same
way-- eg they are b
On Mon, May 31, 2010 at 06:42, unruh wrote:
> Note, that this is one of the reasons why your customers should never
> use 2 servers. You have no way to know which one is crazy. Use 3 or 5.
> (4 can be as bad as 2 if two of the servers go nuts in exactly the same
> way-- eg they are both tied to a
unruh wrote:
On 2010-05-30, Richard B. Gilbert wrote:
bombjack wrote:
Hi,
I am fairly new to the ntp arena, but have to learn fast as part of my
work is trying to fix ntp problems. Lately I had a customer that
complained that there servers went bananas due to time being wrong.
(The customer cl
bombjack wrote:
yes, I know. ntpd is started with the -g flag, which will disable this
safety. Don't ask me why though. I was not working with this when they
came up with the config.
What typically happens is that the standard setting prove too
restrictive for many people (e.g. in this case d
"unruh" wrote in message
news:slrni06c8h.l1a.un...@wormhole.physics.ubc.ca...
> That only requires 3 servers. And 4 has a problem that two can wander
> off togetehr ( eg both depend on the same bad timesource). and then the
> two groups cannot outvote each other either.
You are, of course, rig
First of all, thanks all for replying!
@David:
>ntpd will not change the time by more than 1,000 seconds unless you
deliberately disable the safeties.
yes, I know. ntpd is started with the -g flag, which will disable this
safety. Don't ask me why though. I was not working with this when they
cam
unruh wrote:
Note, that this is one of the reasons why your customers should never
use 2 servers. You have no way to know which one is crazy. Use 3 or 5.
(4 can be as bad as 2 if two of the servers go nuts in exactly the same
way-- eg they are both tied to a single server which has gone nuts).
On 2010-05-30, bombjack wrote:
> Hi,
> I am fairly new to the ntp arena, but have to learn fast as part of my
> work is trying to fix ntp problems. Lately I had a customer that
> complained that there servers went bananas due to time being wrong.
> (The customer claims that ntp had changed the tim
On 2010-05-30, Richard B. Gilbert wrote:
> bombjack wrote:
>> Hi,
>> I am fairly new to the ntp arena, but have to learn fast as part of my
>> work is trying to fix ntp problems. Lately I had a customer that
>> complained that there servers went bananas due to time being wrong.
>> (The customer cl
bombjack wrote:
Hi,
I am fairly new to the ntp arena, but have to learn fast as part of my
work is trying to fix ntp problems. Lately I had a customer that
complained that there servers went bananas due to time being wrong.
(The customer claims that ntp had changed the time 20 years ahead).
Tha
bombjack wrote:
(The customer claims that ntp had changed the time 20 years ahead).
ntpd will not change the time by more than 1,000 seconds unless you
deliberately disable the safeties.
___
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questions@lists.ntp.org
http://li
Hi,
I am fairly new to the ntp arena, but have to learn fast as part of my
work is trying to fix ntp problems. Lately I had a customer that
complained that there servers went bananas due to time being wrong.
(The customer claims that ntp had changed the time 20 years ahead).
Looking at some wire sh
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