Re: [time-nuts] Warped back to 1993
This seems to impact some, but not all, XL-DC units. At least one of mine was impacted, some of the others were not. I think it depends on firmware version. If you check and set the f68 "Set Year" option this will probably let you get things back to displaying the correct date. At least it worked for the one XL-DC I have which I noted having year roll-over issues earlier... -- Russell Tammy A Wisdom wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 It looks like it affects truetime XL-DC's I just noticed it at my house as well :( ___ 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.
Re: [time-nuts] Warped back to 1993
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 It looks like it affects truetime XL-DC's I just noticed it at my house as well :( On 8/11/13 07:09:40, Magnus Danielson wrote: > If Furuno can supply the FW to update with, we would be more than > happy. > > A slight alteration of the code would suffice... > > if (week < 729) week += 2048; else week += 1024; > > Which would keep them floating for another 1024 weeks. If they then > let us know where the two constats is located so we could modify it > again ourselves we be very happy. > > Cheers, Magnus > > On 08/11/2013 01:29 PM, Azelio Boriani wrote: >> OK, good, found the bug. Now, iwe wish it were possible to >> download the firmware, make the correction and then upload... >> >> On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson >> wrote: >>> On 08/11/2013 05:18 AM, Mark C. Stephens wrote: >>>> Okay this is what worked for me: >>>> >>>> 1. Removed power and antenna. 2. apply power with no >>>> antenna. 3. send :GPS:INIT:DATE 2007,08,11 4. plug antenna >>>> back in. >>>> >>>> For some reason if I used the correct date, the Z3815A warped >>>> back to 1993. >>>> >>>> But I am curious why did this happen today? >>> GPS weeks begin on sundays. Today is first day of week 1753: >>> >>> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 >>> >>> Going back 1024 days gives you week 729 day 0, which occurs on >>> 1993 12 26: >>> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 >>> >>> A simple way to compensate for the lack of bits is to assume >>> wrapping occurs, so week numbers lower than som value actually >>> lacks 1024 weeks. A trivial code like this fixes this: >>> >>> if (week < 729) week += 1024; >>> >>> Brilliant until you reach week 1753. >>> >>> I've seen this happen at 500 and 512. >>> >>> Cheers, Magnus >>> >>>> >>>> --marki >>>> >>>> -Original Message- From: time-nuts-boun...@febo.com >>>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. >>>> Stephens Sent: Sunday, 11 August 2013 1:06 PM To: Discussion >>>> of precise time and frequency measurement Subject: Re: >>>> [time-nuts] Warped back to 1993 >>>> >>>> Hal, I can't get it to take, I keep getting E-350 and the >>>> time does not change. Did you unplug the antenna or anything >>>> while you changed date? >>>> >>>> >>>> >>>> >>>> >>>> -Original Message- From: time-nuts-boun...@febo.com >>>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray >>>> Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of >>>> precise time and frequency measurement Subject: Re: >>>> [time-nuts] Warped back to 1993 >>>> >>>> >>>> ma...@non-stop.com.au said: >>>>> A Z3805A, a Z3815A and 58534A integrated timing antenna all >>>>> think it's 26 Dec 1993. What happened?! >>>>> ___ >>>> Is that off by 1024 weeks? (Looks close, but I haven't >>>> checked the details.) >>>> >>>> There is a week field in the GPS data stream. It's only 10 >>>> bits. >>>> >>>> I had that problem on a Z3801A. It did the right thing after >>>> I told it the date. :GPS:INIT:DATE 2011,12,26 >>>> >>>> >>>> >>> ___ 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. > > ___ 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. > -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJSFRYKAAoJEHJ/lMQe1SM00eQIAKdWyxF+S02ggU6QV6Y8koTk uZgSsJdbJDi2jyq/m1mcN7ywqj2QuOQY87r+Hqcqcz6Ym0D3MinINOKggszUYXDA HGH3thUZt086LtD+znUgQbDIrctzRdnQldVcx8ueEb1TIq+9pT1Y71J42LcxLmjl zaP7QM/ol9tEYZro2ARQHqztE/HwEcpXm7ESLCaFu3av0thGLaON89gdcToRdKOp KmMMtVNr2A6onlYX+OLqDDZcfcLulM4wvhZxuqwQVMDaUAlb8jyhKoKCgHdUsZd1 BNPZqOw2gkJPjyz13XaS7wE51OjKsgJmYrLPE+KzoSetBuqApkMdrCOQgR+jKE4= =pEef -END PGP SIGNATURE- ___ 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.
Re: [time-nuts] Warped back to 1993
Mark and David,
On 08/14/2013 12:24 PM, Mark C. Stephens wrote:
> David, Well Done, your patch has breathed life into some refclocks I thought
> had reached the end of the road.
It should be noted that they way GPS works, most if not all GPS
receivers will process the data properly including leap seconds
information, so it will only be this GPS-time to normal time conversion
which will fail.
It's not like it will go back to 1993 leap-second wise also, it simply
does not have that information.
That's why the mod looks sound to me.
Cheers,
Magnus
>
> --marki
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of David Malone
> Sent: Wednesday, 14 August 2013 5:44 PM
> To: Magnus Danielson
> Cc: time-nuts@febo.com
> Subject: Re: [time-nuts] Warped back to 1993
>
> On Sun, Aug 11, 2013 at 03:12:00PM +0200, Magnus Danielson wrote:
>> I'm sure that the NTP drivers can be hacked to make necessary
>> adjustments without too much code.
> I seem to have been caught by the same time warp (or a similar one) on a GPS
> unit that I've been using with our NTP server since 1999.
> I doubt I will be able to update the firmware, so I've made the change shown
> below to the NTP NMEA refclock. It assumes that your GPS unit might be slow
> by a multiple of 1024 weeks, and trys to get the timestamp within 512 weeks
> of the current system time before feeding it to NTP.
>
> The patch seems to work for me, though it may not be pedantically correct.
> Hal might have some comments on if it could easily be improved. It might be
> an interesting option to have in the NMEA driver, but it does seem a litle
> hacky.
>
> David.
>
>
> --- refclock_nmea.c.orig 2010-11-10 03:38:22.0 +
> +++ refclock_nmea.c 2013-08-13 20:05:44.0 +0100
> @@ -979,6 +1076,8 @@
> date.yearday = 0; /* make sure it's not used */
> DTOLFP(pp->nsec * 1.0e-9, &reftime);
> reftime.l_ui += caltontp(&date);
> + while (reftime.l_i + 512*7*86400 < rd_timestamp.l_i)
> + reftime.l_i += 1024*7*86400;
>
> /* $GPZDG postprocessing first... */
> if (NMEA_GPZDG == sentence) {
> ___
> 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] Warped back to 1993
On 08/14/2013 12:25 PM, Bob Camp wrote: > Hi > > Commercial system: > > 1) GPS is giving wrong time, NTP is still running (as a slave) > 2) GPS is broke > 3) Manufacturer says they won't fix / patch the obsolete GPS > 4) Buy new GPS on company credit card > > Whole process likely takes less than an hour. So true. When the GPS is broke, re-fill with credit card. I've seen this happen to a national network. :P Took more than an hour thought. Cheers, Magnus ___ 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.
Re: [time-nuts] Warped back to 1993
David, Well Done, your patch has breathed life into some refclocks I thought
had reached the end of the road.
--marki
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of David Malone
Sent: Wednesday, 14 August 2013 5:44 PM
To: Magnus Danielson
Cc: time-nuts@febo.com
Subject: Re: [time-nuts] Warped back to 1993
On Sun, Aug 11, 2013 at 03:12:00PM +0200, Magnus Danielson wrote:
> I'm sure that the NTP drivers can be hacked to make necessary
> adjustments without too much code.
I seem to have been caught by the same time warp (or a similar one) on a GPS
unit that I've been using with our NTP server since 1999.
I doubt I will be able to update the firmware, so I've made the change shown
below to the NTP NMEA refclock. It assumes that your GPS unit might be slow by
a multiple of 1024 weeks, and trys to get the timestamp within 512 weeks of the
current system time before feeding it to NTP.
The patch seems to work for me, though it may not be pedantically correct. Hal
might have some comments on if it could easily be improved. It might be an
interesting option to have in the NMEA driver, but it does seem a litle hacky.
David.
--- refclock_nmea.c.orig2010-11-10 03:38:22.0 +
+++ refclock_nmea.c 2013-08-13 20:05:44.0 +0100
@@ -979,6 +1076,8 @@
date.yearday = 0; /* make sure it's not used */
DTOLFP(pp->nsec * 1.0e-9, &reftime);
reftime.l_ui += caltontp(&date);
+ while (reftime.l_i + 512*7*86400 < rd_timestamp.l_i)
+ reftime.l_i += 1024*7*86400;
/* $GPZDG postprocessing first... */
if (NMEA_GPZDG == sentence) {
___
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Re: [time-nuts] Warped back to 1993
Hi Commercial system: 1) GPS is giving wrong time, NTP is still running (as a slave) 2) GPS is broke 3) Manufacturer says they won't fix / patch the obsolete GPS 4) Buy new GPS on company credit card Whole process likely takes less than an hour. Bob On Aug 14, 2013, at 3:58 AM, mc235960 wrote: > > Le 14 août 2013 à 09:44, David Malone a écrit : > >> On Sun, Aug 11, 2013 at 03:12:00PM +0200, Magnus Danielson wrote: >>> I'm sure that the NTP drivers can be hacked to make necessary >>> adjustments without too much code. >> >> I seem to have been caught by the same time warp (or a similar one) >> on a GPS unit that I've been using with our NTP server since 1999. >> I doubt I will be able to update the firmware, so I've made the >> change shown below to the NTP NMEA refclock. It assumes that your >> GPS unit might be slow by a multiple of 1024 weeks, and trys to get >> the timestamp within 512 weeks of the current system time before >> feeding it to NTP. > >Considering the small number of time nuts this issue is taking on leap > second dimensions. I wonder how many commercial systems have had down time > due to this? >I'll have to dig out and test all my sleeping receivers to see which have > turned into boat anchors. > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
Le 14 août 2013 à 09:44, David Malone a écrit : > On Sun, Aug 11, 2013 at 03:12:00PM +0200, Magnus Danielson wrote: >> I'm sure that the NTP drivers can be hacked to make necessary >> adjustments without too much code. > > I seem to have been caught by the same time warp (or a similar one) > on a GPS unit that I've been using with our NTP server since 1999. > I doubt I will be able to update the firmware, so I've made the > change shown below to the NTP NMEA refclock. It assumes that your > GPS unit might be slow by a multiple of 1024 weeks, and trys to get > the timestamp within 512 weeks of the current system time before > feeding it to NTP. Considering the small number of time nuts this issue is taking on leap second dimensions. I wonder how many commercial systems have had down time due to this? I'll have to dig out and test all my sleeping receivers to see which have turned into boat anchors. ___ 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.
Re: [time-nuts] Warped back to 1993
On Sun, Aug 11, 2013 at 03:12:00PM +0200, Magnus Danielson wrote:
> I'm sure that the NTP drivers can be hacked to make necessary
> adjustments without too much code.
I seem to have been caught by the same time warp (or a similar one)
on a GPS unit that I've been using with our NTP server since 1999.
I doubt I will be able to update the firmware, so I've made the
change shown below to the NTP NMEA refclock. It assumes that your
GPS unit might be slow by a multiple of 1024 weeks, and trys to get
the timestamp within 512 weeks of the current system time before
feeding it to NTP.
The patch seems to work for me, though it may not be pedantically
correct. Hal might have some comments on if it could easily be
improved. It might be an interesting option to have in the NMEA
driver, but it does seem a litle hacky.
David.
--- refclock_nmea.c.orig2010-11-10 03:38:22.0 +
+++ refclock_nmea.c 2013-08-13 20:05:44.0 +0100
@@ -979,6 +1076,8 @@
date.yearday = 0; /* make sure it's not used */
DTOLFP(pp->nsec * 1.0e-9, &reftime);
reftime.l_ui += caltontp(&date);
+ while (reftime.l_i + 512*7*86400 < rd_timestamp.l_i)
+ reftime.l_i += 1024*7*86400;
/* $GPZDG postprocessing first... */
if (NMEA_GPZDG == sentence) {
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Re: [time-nuts] Warped back to 1993 vs. ntp
Hi I agree that if you are using GPS simply as a PPS source, then this isn't quite as important. I believe that some are using GPS as a time of day (etc) source as well. I think that the how / why / what of doing this with NTP probably belongs over on the NTP list. The issue is a bit broader than just NTP and it does apply to time from GPS in general. Bob On Aug 11, 2013, at 6:40 PM, Paul wrote: > I don't* number my seconds with my PPS devices so as long as the PPS > tracks the GPS system the reported date is irrelevant. If this > problem effects an ntp controlled clock group I think it means you're > misconfigured** e.g. misusing the TRUE option. > > * Well not quite true but the point remains. > ** Having all your primary clocks running identical hardware is > probably a misconfiguration too. > ___ > 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.
[time-nuts] Warped back to 1993 vs. ntp
I don't* number my seconds with my PPS devices so as long as the PPS tracks the GPS system the reported date is irrelevant. If this problem effects an ntp controlled clock group I think it means you're misconfigured** e.g. misusing the TRUE option. * Well not quite true but the point remains. ** Having all your primary clocks running identical hardware is probably a misconfiguration too. ___ 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.
Re: [time-nuts] Warped back to 1993
Hi On Aug 11, 2013, at 6:07 PM, Magnus Danielson wrote: > On 08/11/2013 11:32 PM, Hal Murray wrote: >> li...@rtty.us said: >>> The issue with the fudge option is that you need to engage it at exactly the >>> right point. Put another way, there's a period between it failing and your >>> entering a fudge that the NTP server is down. >> Yup. But if you are running along and suddenly your GPS breaks, you might >> be >> able to fix it by editing a config file and not needing to install any new >> software or wait for the bug to get fixed. >> >>> With a couple lines of auto correct code in there, it would (essentially) >>> never fail. If you are running a GPS, you enable the auto-correction and >>> forget about it. My guess is that many GPS devices will eventually suffer >>> from the wrap around >> Agreed. >> >> >>> The only way they could avoid it would be some sort of external correction >>> (like continuous firmware updates) or a "no reverse" on the year. Both >>> approaches have their drawbacks….. >> There is another option that may be good-enough for some/many of us. That >> is >> a way to tell the GPS unit the date. >> >> If a GPS device knows the rough date, it can get the right answer. >> >> Most GPS units have a battery and 32KHz clock to keep track of the time so >> they can get started (much) quicker on power up: warm start vs cold start. >> This isn't quite "no reverse", but it's pretty close. >> >> 1024 weeks is 20 years, so the batteries are probably old by the time this >> gets interesting. But even an old tired battery might keep a clock ticking >> for a few minutes/hours. That might cover rearranging cables or a >> not-too-long power outage. >> >> But after the unit has been powered off too long (relative to the battery) >> or >> after you replace the battery, you need some way to set the date. >> >> My Z3801A has been happy since I told it the date. I don't know if it has >> been powered off since then. I should probably try the experiment. >> >> >> > The problem is not that it is hard to encode a solution such that with > some user-setting you can get the right date. It is what we hope is in > there. The problem is that so many recievers use the wrapped time > quick-fix as it was sufficient for the expected life-time of the > product. Most of the things it do does not really depend on it, other > than cranking out a date which looks OKish. If we care, we can > compensate accurately for it, if we have an rough idea of the date... > that is, code around the internal limit and achieve what should have > been in there from the start. Not ideal, but will work. > All we really would need to know is the date to within a decade. Past that it's pretty easy. It's more like an error correcting code than anything else. A fully automated solution would be vulnerable to a multi decade glitch, so I'd allow both a fully automated solution and a "tell me the decade" solution. If I want to supply the config file with a date once a year, I'm good for quite a while….. In some ways this is a bit like the leap second debate. With enough warning (10 years) it's not a big issue. Bob > Cheers, > Magnus > ___ > 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.
Re: [time-nuts] Warped back to 1993
On 08/11/2013 11:32 PM, Hal Murray wrote: > li...@rtty.us said: >> The issue with the fudge option is that you need to engage it at exactly the >> right point. Put another way, there's a period between it failing and your >> entering a fudge that the NTP server is down. > Yup. But if you are running along and suddenly your GPS breaks, you might be > able to fix it by editing a config file and not needing to install any new > software or wait for the bug to get fixed. > >> With a couple lines of auto correct code in there, it would (essentially) >> never fail. If you are running a GPS, you enable the auto-correction and >> forget about it. My guess is that many GPS devices will eventually suffer >> from the wrap around > Agreed. > > >> The only way they could avoid it would be some sort of external correction >> (like continuous firmware updates) or a "no reverse" on the year. Both >> approaches have their drawbacks….. > There is another option that may be good-enough for some/many of us. That is > a way to tell the GPS unit the date. > > If a GPS device knows the rough date, it can get the right answer. > > Most GPS units have a battery and 32KHz clock to keep track of the time so > they can get started (much) quicker on power up: warm start vs cold start. > This isn't quite "no reverse", but it's pretty close. > > 1024 weeks is 20 years, so the batteries are probably old by the time this > gets interesting. But even an old tired battery might keep a clock ticking > for a few minutes/hours. That might cover rearranging cables or a > not-too-long power outage. > > But after the unit has been powered off too long (relative to the battery) or > after you replace the battery, you need some way to set the date. > > My Z3801A has been happy since I told it the date. I don't know if it has > been powered off since then. I should probably try the experiment. > > > The problem is not that it is hard to encode a solution such that with some user-setting you can get the right date. It is what we hope is in there. The problem is that so many recievers use the wrapped time quick-fix as it was sufficient for the expected life-time of the product. Most of the things it do does not really depend on it, other than cranking out a date which looks OKish. If we care, we can compensate accurately for it, if we have an rough idea of the date... that is, code around the internal limit and achieve what should have been in there from the start. Not ideal, but will work. Cheers, Magnus ___ 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.
Re: [time-nuts] Warped back to 1993
Hi On Aug 11, 2013, at 5:32 PM, Hal Murray wrote: > > li...@rtty.us said: >> The issue with the fudge option is that you need to engage it at exactly the >> right point. Put another way, there's a period between it failing and your >> entering a fudge that the NTP server is down. > > Yup. But if you are running along and suddenly your GPS breaks, you might be > able to fix it by editing a config file and not needing to install any new > software or wait for the bug to get fixed. If you only "fix" it modulo 1024 when instructed, there isn't the same downside as a "change it all over the place" sort of solution. > >> With a couple lines of auto correct code in there, it would (essentially) >> never fail. If you are running a GPS, you enable the auto-correction and >> forget about it. My guess is that many GPS devices will eventually suffer >> from the wrap around > > Agreed. > > >> The only way they could avoid it would be some sort of external correction >> (like continuous firmware updates) or a "no reverse" on the year. Both >> approaches have their drawbacks….. > > There is another option that may be good-enough for some/many of us. That is > a way to tell the GPS unit the date. That *assumes* that the GPS firmware will accept a date as an input. The firmware would need to be able to do this. > > If a GPS device knows the rough date, it can get the right answer. > > Most GPS units have a battery and 32KHz clock to keep track of the time so > they can get started (much) quicker on power up: warm start vs cold start. > This isn't quite "no reverse", but it's pretty close. > > 1024 weeks is 20 years, so the batteries are probably old by the time this > gets interesting. But even an old tired battery might keep a clock ticking > for a few minutes/hours. That might cover rearranging cables or a > not-too-long power outage. > > But after the unit has been powered off too long (relative to the battery) or > after you replace the battery, you need some way to set the date. > > My Z3801A has been happy since I told it the date. I don't know if it has > been powered off since then. I should probably try the experiment. Z3805's and later have multiple receivers in them. Different firmware will / may fail at different times. Bob > > > > -- > These are my opinions. I hate spam. > > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
li...@rtty.us said: > The issue with the fudge option is that you need to engage it at exactly the > right point. Put another way, there's a period between it failing and your > entering a fudge that the NTP server is down. Yup. But if you are running along and suddenly your GPS breaks, you might be able to fix it by editing a config file and not needing to install any new software or wait for the bug to get fixed. > With a couple lines of auto correct code in there, it would (essentially) > never fail. If you are running a GPS, you enable the auto-correction and > forget about it. My guess is that many GPS devices will eventually suffer > from the wrap around Agreed. > The only way they could avoid it would be some sort of external correction > (like continuous firmware updates) or a "no reverse" on the year. Both > approaches have their drawbacks .. There is another option that may be good-enough for some/many of us. That is a way to tell the GPS unit the date. If a GPS device knows the rough date, it can get the right answer. Most GPS units have a battery and 32KHz clock to keep track of the time so they can get started (much) quicker on power up: warm start vs cold start. This isn't quite "no reverse", but it's pretty close. 1024 weeks is 20 years, so the batteries are probably old by the time this gets interesting. But even an old tired battery might keep a clock ticking for a few minutes/hours. That might cover rearranging cables or a not-too-long power outage. But after the unit has been powered off too long (relative to the battery) or after you replace the battery, you need some way to set the date. My Z3801A has been happy since I told it the date. I don't know if it has been powered off since then. I should probably try the experiment. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Warped back to 1993
Hi If we are keeping this stuff running for decades (think of the WWII stuff we still try to use) then we need a long term / across the board fix. Making all the vendors open source their firmware is one way, I doubt it will work. Reverse engineering all the firmware is also unlikely to be an across the board solution. The only real way I see is to adapt to it. Bob On Aug 11, 2013, at 4:01 PM, Hal Murray wrote: > > als...@nc.rr.com said: >> Is the change cumulative? In other words is one tries 2^n times, could you >> get there? > > I don't think so. Even if it did a += rather than an =, you still have the > problem of a float not being big enough to hold 1024 weeks plus a few ms. > > >> Turns out guys have hacked the 2072 to turn it into a 2202 bandwidth et al. > > Is that a soldering iron change or just firmware? > > > > > -- > These are my opinions. I hate spam. > > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
als...@nc.rr.com said: > Is the change cumulative? In other words is one tries 2^n times, could you > get there? I don't think so. Even if it did a += rather than an =, you still have the problem of a float not being big enough to hold 1024 weeks plus a few ms. > Turns out guys have hacked the 2072 to turn it into a 2202 bandwidth et al. Is that a soldering iron change or just firmware? -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Warped back to 1993
Hi I'd claim that the modulo 1024 wrap is a "known issue" with GPS. I would not force the correction on all users. I'd just make it an optional item. This obviously also applies to things like LH and other TimeNut stuff. As we try to keep the gear going much longer than the original designers anticipated, and as manufacturers drop firmware support, we're going to need a generic solution for the issue. "Forcing" manufacturers to fix stuff long after it's gone obsolete isn't the answer…. Bob On Aug 11, 2013, at 3:45 PM, Martin Burnicki wrote: > Bob Camp wrote: >> Hi >> >> The issue with the fudge option is that you need to engage it at >> exactly the right point. Put another way, there's a period between it >> failing and your entering a fudge that the NTP server is down. > > The question is whether you know in advance *when* the problem will occur. > > If you observe that your GPS sends a wrong date you are already after the > point where the bug started to occur, so you can safely add a fudge value to > get this working for the next 1024 weeks. > >> With a >> couple lines of auto correct code in there, it would (essentially) >> never fail. If you are running a GPS, you enable the auto-correction >> and forget about it. My guess is that many GPS devices will >> eventually suffer from the wrap around. The only way they could >> avoid it would be some sort of external correction (like continuous >> firmware updates) or a "no reverse" on the year. Both approaches have >> their drawbacks….. > > Unless you know the source code of the firmware you can only assume what is > the reason for the wrong date being sent. I'm not sure whether a piece of > software like ntpd should try to work around all possible kinds of firmware > bugs in all possible types of GPS receivers. > > Martin > > ___ > 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.
Re: [time-nuts] Warped back to 1993
Bob Camp wrote: Hi The issue with the fudge option is that you need to engage it at exactly the right point. Put another way, there's a period between it failing and your entering a fudge that the NTP server is down. The question is whether you know in advance *when* the problem will occur. If you observe that your GPS sends a wrong date you are already after the point where the bug started to occur, so you can safely add a fudge value to get this working for the next 1024 weeks. With a couple lines of auto correct code in there, it would (essentially) never fail. If you are running a GPS, you enable the auto-correction and forget about it. My guess is that many GPS devices will eventually suffer from the wrap around. The only way they could avoid it would be some sort of external correction (like continuous firmware updates) or a "no reverse" on the year. Both approaches have their drawbacks….. Unless you know the source code of the firmware you can only assume what is the reason for the wrong date being sent. I'm not sure whether a piece of software like ntpd should try to work around all possible kinds of firmware bugs in all possible types of GPS receivers. Martin ___ 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.
Re: [time-nuts] Warped back to 1993
Hi The issue with the fudge option is that you need to engage it at exactly the right point. Put another way, there's a period between it failing and your entering a fudge that the NTP server is down. With a couple lines of auto correct code in there, it would (essentially) never fail. If you are running a GPS, you enable the auto-correction and forget about it. My guess is that many GPS devices will eventually suffer from the wrap around. The only way they could avoid it would be some sort of external correction (like continuous firmware updates) or a "no reverse" on the year. Both approaches have their drawbacks….. Bob On Aug 11, 2013, at 1:51 PM, Hal Murray wrote: > > mag...@rubidium.dyndns.org said: >> I'm sure that the NTP drivers can be hacked to make necessary adjustments >> without too much code. > > The code is already in there. It's got a fudge option in the config file. > That was intended to fixup small offsets. I think it will work with big > offsets too. > > 1024 weeks is 1024*7*86400 seconds. That's 0x24EA, 30 bits. It won't > fit in a float if you also need to correct for a few ms, but it should work > if you changed enough stuff from floats to doubles. They are likely to be > doubles already. > > It would be fun to try. > > > -- > These are my opinions. I hate spam. > > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
Hal, Is the change cumulative? In other words is one tries 2^n times, could you get there? BTW. Thanks for your advice on scopes. I finally ordered a DS1102. I had ordered a DS2072 but it would have been 4-6 weeks till arrival, if then. In the interim, I convinced myself a 2072 would have been a like trying to hold a tiger by the tail. Play with the cheaper version for learning purposes. I was also turned off by the metal heat sink holddowns popping off inside the unit. While a repair would be easy, one would void the warranty. Turns out guys have hacked the 2072 to turn it into a 2202 bandwidth et al. 73 de Brian/K3KO On 8/11/2013 17:51, Hal Murray wrote: mag...@rubidium.dyndns.org said: I'm sure that the NTP drivers can be hacked to make necessary adjustments without too much code. The code is already in there. It's got a fudge option in the config file. That was intended to fixup small offsets. I think it will work with big offsets too. 1024 weeks is 1024*7*86400 seconds. That's 0x24EA, 30 bits. It won't fit in a float if you also need to correct for a few ms, but it should work if you changed enough stuff from floats to doubles. They are likely to be doubles already. It would be fun to try. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3211/6069 - Release Date: 08/11/13 ___ 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.
Re: [time-nuts] Warped back to 1993
On 08/11/2013 07:39 PM, Mark Sims wrote: > According to the Thunderbolt manual on July 30, 2017 Tbolts will experience a > rollover error. > In version 4 of Lady Heather (being developed), I have added a rollover > compensation mechanism. If the GPS year is less than the OS year, 1024 > weeks is added to the GPS time until the year catches up. Or you can > manually specify a rollover offset or disable the feature. 2017 07 30 = 1960 0 That means that it uses GPS week 936 as base for it's wrap around limit. Makes sense. Should we ask Trimble for FW upgrade already now? Cheers, Magnus ___ 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.
Re: [time-nuts] Warped back to 1993
mag...@rubidium.dyndns.org said: > I'm sure that the NTP drivers can be hacked to make necessary adjustments > without too much code. The code is already in there. It's got a fudge option in the config file. That was intended to fixup small offsets. I think it will work with big offsets too. 1024 weeks is 1024*7*86400 seconds. That's 0x24EA, 30 bits. It won't fit in a float if you also need to correct for a few ms, but it should work if you changed enough stuff from floats to doubles. They are likely to be doubles already. It would be fun to try. -- These are my opinions. I hate spam. ___ 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] Warped back to 1993
According to the Thunderbolt manual on July 30, 2017 Tbolts will experience a rollover error. In version 4 of Lady Heather (being developed), I have added a rollover compensation mechanism. If the GPS year is less than the OS year, 1024 weeks is added to the GPS time until the year catches up. Or you can manually specify a rollover offset or disable the feature. ___ 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.
Re: [time-nuts] Warped back to 1993
Hi I think that without much risk, you could put in a "gps epoch" setting in the ntp configuration file. More or less make it a "check and correct if needed" sort of thing. No setting in the file would mean disable the check and correct code. Bob On Aug 11, 2013, at 12:58 PM, Martin Burnicki wrote: > Bob Camp wrote: >> Hi >> >> … and since NTP is open source, doing the hack is not dependent on getting a >> new firmware image for the GPS. > > Hacking ntpd is one possibility, with the risk that a workaround for some > broken GPS receiver also affects GPS receivers which are working correctly. > > At least in some of ntpd's refclock drivers you can configure a fixed offset > using a "fudge time1 ..." command., e.g. for the parse driver > > fudge 127.127.8.0 time1 7200 > > would add a 7200 s offset to the time from the refclock. As far as I know > this also works for larger offsets, at least with the parse driver, and this > possibly can also be used to fix a constant offset for broken GPS receivers, > depending of the refclock driver used. > > Anyway, I think it's worth a try, and it would not require any code change in > ntpd or the firmware. > > Martin > > ___ > 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.
Re: [time-nuts] Warped back to 1993
Hi Well, if it works fine as a GPSDO, and NTP can be fixed to work with it, that covers ninety something percent of what most people do with this sort of stuff. Bob On Aug 11, 2013, at 9:43 AM, Magnus Danielson wrote: > Hi Bob, > > On 08/11/2013 03:37 PM, Bob Camp wrote: >> Hi >> >> … and since NTP is open source, doing the hack is not dependent on getting a >> new firmware image for the GPS. > Yes, but it only helps the NTP side of things. > > Made a point about the wrap-around-compensation on one of the NTP lists > just now, they happen to get things a bit confused for a moment. > > Still, it would be good if they could keep FW updates available. > Naturally, if they could drop the sources my way I would enjoy that even > more. > > Cheers, > Magnus > ___ > 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.
Re: [time-nuts] Warped back to 1993
Bob Camp wrote: Hi … and since NTP is open source, doing the hack is not dependent on getting a new firmware image for the GPS. Hacking ntpd is one possibility, with the risk that a workaround for some broken GPS receiver also affects GPS receivers which are working correctly. At least in some of ntpd's refclock drivers you can configure a fixed offset using a "fudge time1 ..." command., e.g. for the parse driver fudge 127.127.8.0 time1 7200 would add a 7200 s offset to the time from the refclock. As far as I know this also works for larger offsets, at least with the parse driver, and this possibly can also be used to fix a constant offset for broken GPS receivers, depending of the refclock driver used. Anyway, I think it's worth a try, and it would not require any code change in ntpd or the firmware. Martin ___ 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.
Re: [time-nuts] Warped back to 1993
Furuno will not give you the time of day :-) :-) Don Magnus Danielson > Hi Bob, > > On 08/11/2013 03:37 PM, Bob Camp wrote: >> Hi >> >> and since NTP is open source, doing the hack is not dependent on >> getting a new firmware image for the GPS. > Yes, but it only helps the NTP side of things. > > Made a point about the wrap-around-compensation on one of the NTP lists > just now, they happen to get things a bit confused for a moment. > > Still, it would be good if they could keep FW updates available. > Naturally, if they could drop the sources my way I would enjoy that even > more. > > Cheers, > Magnus > ___ > 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. > > -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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.
Re: [time-nuts] Warped back to 1993
At least one my Z3805's is also showing a date from 1993. ___ 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.
Re: [time-nuts] Warped back to 1993
Hi Bob, On 08/11/2013 03:37 PM, Bob Camp wrote: > Hi > > … and since NTP is open source, doing the hack is not dependent on getting a > new firmware image for the GPS. Yes, but it only helps the NTP side of things. Made a point about the wrap-around-compensation on one of the NTP lists just now, they happen to get things a bit confused for a moment. Still, it would be good if they could keep FW updates available. Naturally, if they could drop the sources my way I would enjoy that even more. Cheers, Magnus ___ 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.
Re: [time-nuts] Warped back to 1993
Hi … and since NTP is open source, doing the hack is not dependent on getting a new firmware image for the GPS. Bob On Aug 11, 2013, at 9:12 AM, Magnus Danielson wrote: > On 08/11/2013 03:08 PM, Bob Camp wrote: >> Hi >> >> One point worth mentioning - the device will still be quite happy acting as >> a GPSDO. It simply will not be of much use for NTP (or any other date >> dependent system). > I'm sure that the NTP drivers can be hacked to make necessary > adjustments without too much code. > > It is after all very likely that a GPS clock has wrapped a multiple of > 1024 weeks. > > Cheers, > Magnus > ___ > 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.
Re: [time-nuts] Warped back to 1993
On 08/11/2013 03:08 PM, Bob Camp wrote: > Hi > > One point worth mentioning - the device will still be quite happy acting as a > GPSDO. It simply will not be of much use for NTP (or any other date dependent > system). I'm sure that the NTP drivers can be hacked to make necessary adjustments without too much code. It is after all very likely that a GPS clock has wrapped a multiple of 1024 weeks. Cheers, Magnus ___ 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.
Re: [time-nuts] Warped back to 1993
If Furuno can supply the FW to update with, we would be more than happy. A slight alteration of the code would suffice... if (week < 729) week += 2048; else week += 1024; Which would keep them floating for another 1024 weeks. If they then let us know where the two constats is located so we could modify it again ourselves we be very happy. Cheers, Magnus On 08/11/2013 01:29 PM, Azelio Boriani wrote: > OK, good, found the bug. Now, iwe wish it were possible to download > the firmware, make the correction and then upload... > > On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson > wrote: >> On 08/11/2013 05:18 AM, Mark C. Stephens wrote: >>> Okay this is what worked for me: >>> >>> 1. Removed power and antenna. >>> 2. apply power with no antenna. >>> 3. send :GPS:INIT:DATE 2007,08,11 >>> 4. plug antenna back in. >>> >>> For some reason if I used the correct date, the Z3815A warped back to 1993. >>> >>> But I am curious why did this happen today? >> GPS weeks begin on sundays. Today is first day of week 1753: >> >> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 >> >> Going back 1024 days gives you week 729 day 0, which occurs on 1993 12 26: >> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 >> >> A simple way to compensate for the lack of bits is to assume wrapping >> occurs, so week numbers lower than som value actually lacks 1024 weeks. >> A trivial code like this fixes this: >> >> if (week < 729) >> week += 1024; >> >> Brilliant until you reach week 1753. >> >> I've seen this happen at 500 and 512. >> >> Cheers, >> Magnus >> >>> >>> --marki >>> >>> -Original Message- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >>> Behalf Of Mark C. Stephens >>> Sent: Sunday, 11 August 2013 1:06 PM >>> To: Discussion of precise time and frequency measurement >>> Subject: Re: [time-nuts] Warped back to 1993 >>> >>> Hal, I can't get it to take, I keep getting E-350 and the time does not >>> change. >>> Did you unplug the antenna or anything while you changed date? >>> >>> >>> >>> >>> >>> -Original Message- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >>> Behalf Of Hal Murray >>> Sent: Sunday, 11 August 2013 12:54 PM >>> To: Discussion of precise time and frequency measurement >>> Subject: Re: [time-nuts] Warped back to 1993 >>> >>> >>> ma...@non-stop.com.au said: >>>> A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's >>>> 26 Dec 1993. >>>> What happened?! ___ >>> Is that off by 1024 weeks? (Looks close, but I haven't checked the >>> details.) >>> >>> There is a week field in the GPS data stream. It's only 10 bits. >>> >>> I had that problem on a Z3801A. It did the right thing after I told it the >>> date. >>> :GPS:INIT:DATE 2011,12,26 >>> >>> >>> >> ___ >> 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. ___ 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.
Re: [time-nuts] Warped back to 1993
Hi One point worth mentioning - the device will still be quite happy acting as a GPSDO. It simply will not be of much use for NTP (or any other date dependent system). Bob On Aug 11, 2013, at 7:44 AM, Mark C. Stephens wrote: > Azelio, is your Furuno playing up? > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Azelio Boriani > Sent: Sunday, 11 August 2013 9:30 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Warped back to 1993 > > OK, good, found the bug. Now, iwe wish it were possible to download the > firmware, make the correction and then upload... > > On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson > wrote: >> On 08/11/2013 05:18 AM, Mark C. Stephens wrote: >>> Okay this is what worked for me: >>> >>> 1. Removed power and antenna. >>> 2. apply power with no antenna. >>> 3. send :GPS:INIT:DATE 2007,08,11 >>> 4. plug antenna back in. >>> >>> For some reason if I used the correct date, the Z3815A warped back to 1993. >>> >>> But I am curious why did this happen today? >> GPS weeks begin on sundays. Today is first day of week 1753: >> >> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 >> >> Going back 1024 days gives you week 729 day 0, which occurs on 1993 12 26: >> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 >> >> A simple way to compensate for the lack of bits is to assume wrapping >> occurs, so week numbers lower than som value actually lacks 1024 weeks. >> A trivial code like this fixes this: >> >> if (week < 729) >>week += 1024; >> >> Brilliant until you reach week 1753. >> >> I've seen this happen at 500 and 512. >> >> Cheers, >> Magnus >> >>> >>> >>> --marki >>> >>> -Original Message- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] >>> On Behalf Of Mark C. Stephens >>> Sent: Sunday, 11 August 2013 1:06 PM >>> To: Discussion of precise time and frequency measurement >>> Subject: Re: [time-nuts] Warped back to 1993 >>> >>> Hal, I can't get it to take, I keep getting E-350 and the time does not >>> change. >>> Did you unplug the antenna or anything while you changed date? >>> >>> >>> >>> >>> >>> -Original Message- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] >>> On Behalf Of Hal Murray >>> Sent: Sunday, 11 August 2013 12:54 PM >>> To: Discussion of precise time and frequency measurement >>> Subject: Re: [time-nuts] Warped back to 1993 >>> >>> >>> ma...@non-stop.com.au said: >>>> A Z3805A, a Z3815A and 58534A integrated timing antenna all think >>>> it's >>>> 26 Dec 1993. >>>> What happened?! ___ >>> Is that off by 1024 weeks? (Looks close, but I haven't checked the >>> details.) >>> >>> There is a week field in the GPS data stream. It's only 10 bits. >>> >>> I had that problem on a Z3801A. It did the right thing after I told it the >>> date. >>> :GPS:INIT:DATE 2011,12,26 >>> >>> >>> >> >> ___ >> 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. > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
Azelio, is your Furuno playing up? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 11 August 2013 9:30 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 OK, good, found the bug. Now, iwe wish it were possible to download the firmware, make the correction and then upload... On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson wrote: > On 08/11/2013 05:18 AM, Mark C. Stephens wrote: >> Okay this is what worked for me: >> >> 1. Removed power and antenna. >> 2. apply power with no antenna. >> 3. send :GPS:INIT:DATE 2007,08,11 >> 4. plug antenna back in. >> >> For some reason if I used the correct date, the Z3815A warped back to 1993. >> >> But I am curious why did this happen today? > GPS weeks begin on sundays. Today is first day of week 1753: > > http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 > > Going back 1024 days gives you week 729 day 0, which occurs on 1993 12 26: > http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 > > A simple way to compensate for the lack of bits is to assume wrapping > occurs, so week numbers lower than som value actually lacks 1024 weeks. > A trivial code like this fixes this: > > if (week < 729) > week += 1024; > > Brilliant until you reach week 1753. > > I've seen this happen at 500 and 512. > > Cheers, > Magnus > >> >> >> --marki >> >> -Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] >> On Behalf Of Mark C. Stephens >> Sent: Sunday, 11 August 2013 1:06 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Warped back to 1993 >> >> Hal, I can't get it to take, I keep getting E-350 and the time does not >> change. >> Did you unplug the antenna or anything while you changed date? >> >> >> >> >> >> -----Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] >> On Behalf Of Hal Murray >> Sent: Sunday, 11 August 2013 12:54 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Warped back to 1993 >> >> >> ma...@non-stop.com.au said: >>> A Z3805A, a Z3815A and 58534A integrated timing antenna all think >>> it's >>> 26 Dec 1993. >>> What happened?! ___ >> Is that off by 1024 weeks? (Looks close, but I haven't checked the >> details.) >> >> There is a week field in the GPS data stream. It's only 10 bits. >> >> I had that problem on a Z3801A. It did the right thing after I told it the >> date. >> :GPS:INIT:DATE 2011,12,26 >> >> >> > > ___ > 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. ___ 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.
Re: [time-nuts] Warped back to 1993
OK, good, found the bug. Now, iwe wish it were possible to download the firmware, make the correction and then upload... On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson wrote: > On 08/11/2013 05:18 AM, Mark C. Stephens wrote: >> Okay this is what worked for me: >> >> 1. Removed power and antenna. >> 2. apply power with no antenna. >> 3. send :GPS:INIT:DATE 2007,08,11 >> 4. plug antenna back in. >> >> For some reason if I used the correct date, the Z3815A warped back to 1993. >> >> But I am curious why did this happen today? > GPS weeks begin on sundays. Today is first day of week 1753: > > http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 > > Going back 1024 days gives you week 729 day 0, which occurs on 1993 12 26: > http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 > > A simple way to compensate for the lack of bits is to assume wrapping > occurs, so week numbers lower than som value actually lacks 1024 weeks. > A trivial code like this fixes this: > > if (week < 729) > week += 1024; > > Brilliant until you reach week 1753. > > I've seen this happen at 500 and 512. > > Cheers, > Magnus > >> >> >> --marki >> >> -Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Mark C. Stephens >> Sent: Sunday, 11 August 2013 1:06 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Warped back to 1993 >> >> Hal, I can't get it to take, I keep getting E-350 and the time does not >> change. >> Did you unplug the antenna or anything while you changed date? >> >> >> >> >> >> -----Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Hal Murray >> Sent: Sunday, 11 August 2013 12:54 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Warped back to 1993 >> >> >> ma...@non-stop.com.au said: >>> A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's >>> 26 Dec 1993. >>> What happened?! ___ >> Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) >> >> There is a week field in the GPS data stream. It's only 10 bits. >> >> I had that problem on a Z3801A. It did the right thing after I told it the >> date. >> :GPS:INIT:DATE 2011,12,26 >> >> >> > > ___ > 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.
Re: [time-nuts] Warped back to 1993
On 08/11/2013 07:07 AM, Hal Murray wrote:
>> With the wrong date and time, the GPS should not find almanac data, so will
>> not lock.
> I don't think that's the right way of describing the problem.
>
> The satellites broadcast on a known frequency, but that gets shifted all over
> the place by Doppler. ("All over" means a big shift relative to the
> bandwidth of the signal.)
>
> If you have a recent almanac and you know the date/time and location, then
> you can compute the Doppler and look in the right frequency and find the
> satellites quickly. In this context, "find" means hearing a signal at an
> expected frequency. If you don't hear anything where you expect it, then you
> get to check nearby frequencies. If you don't find anything nearby, you get
> to give up and start searching the whole Doppler range. It's the difference
> between warm start and cold start.
>
> Once you do find several satellites, you can figure out the date/time and
> location and after a while get a new almanac.
You only need to find a single satellite to get rough GPS time and the
full almanac.
You don't need the almanac, time or position to search the full doppler
and code bins for all 32 codes, it just takes time. Once you got the
first bird, you start to get the almanac, if the user supplies a rough
guess of position (or it has been stored) you can speed up the process,
if you have a recent enough almanac you can also speed things up using a
rough position, as you stop wasting time on birds you likely won't see.
But really, with completely wiped memory, you can get lock, it's more an
issue of start-up time.
Cheers,
Magnus
___
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.
Re: [time-nuts] Warped back to 1993
On 08/11/2013 05:18 AM, Mark C. Stephens wrote: > Okay this is what worked for me: > > 1. Removed power and antenna. > 2. apply power with no antenna. > 3. send :GPS:INIT:DATE 2007,08,11 > 4. plug antenna back in. > > For some reason if I used the correct date, the Z3815A warped back to 1993. > > But I am curious why did this happen today? GPS weeks begin on sundays. Today is first day of week 1753: http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 Going back 1024 days gives you week 729 day 0, which occurs on 1993 12 26: http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 A simple way to compensate for the lack of bits is to assume wrapping occurs, so week numbers lower than som value actually lacks 1024 weeks. A trivial code like this fixes this: if (week < 729) week += 1024; Brilliant until you reach week 1753. I've seen this happen at 500 and 512. Cheers, Magnus > > > --marki > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Mark C. Stephens > Sent: Sunday, 11 August 2013 1:06 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Warped back to 1993 > > Hal, I can't get it to take, I keep getting E-350 and the time does not > change. > Did you unplug the antenna or anything while you changed date? > > > > > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Hal Murray > Sent: Sunday, 11 August 2013 12:54 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Warped back to 1993 > > > ma...@non-stop.com.au said: >> A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's >> 26 Dec 1993. >> What happened?! ___ > Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) > > There is a week field in the GPS data stream. It's only 10 bits. > > I had that problem on a Z3801A. It did the right thing after I told it the > date. > :GPS:INIT:DATE 2011,12,26 > > > ___ 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.
Re: [time-nuts] Warped back to 1993
bg wrote: As has been discussed here before. The GPS firmware programmer finalizing his stuff at GPS week X (approaching 1024) will make sure his receiver will survive until X weeks into the next era. What X is is hard for the end user to know. 1024 weeks is long time beyond normal warranties. Right, this is one possible reason. I have seen era predictions based on # of leap seconds. But that particular implementation did not fare well with long leapsecondless periods we had. I remember a discussion about this way to guess the epoch. Depending on the implementation and the intervals between leap seconds about 15 years ago, and looking at the large intervals between the last leap seconds, this may also fail. A much simpler way to handle this is to provide a way where the user can enter the current date, and the firmware determines the correct epoch and week number. This also had to be done only once if a receiver was powered up from scratch. If the receiver knows it has already been operating at a date after one or more rollovers it can easily get the right epoch. Martin ___ 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.
Re: [time-nuts] Warped back to 1993
As has been discussed here before. The GPS firmware programmer finalizing his stuff at GPS week X (approaching 1024) will make sure his receiver will survive until X weeks into the next era. What X is is hard for the end user to know. 1024 weeks is long time beyond normal warranties. I have seen era predictions based on # of leap seconds. But that particular implementation did not fare well with long leapsecondless periods we had. /Björn Skickat från min Mobil Originalmeddelande Från: "Mark C. Stephens" Datum: 2013-08-11 11:04 (GMT+01:00) Till: Discussion of precise time and frequency measurement Rubrik: Re: [time-nuts] Warped back to 1993 Yep Sorry, I see what you mean, can't be the GPS week rollover bug then. I am at a loss to explain this one then. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 6:33 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Please explain what happened today then? Also, the 2 module that I cannot set to the correct date are both Furino GT-77's. Over on the NTP list they are claiming it's the start of the new GPS 1024 week epoch. If you have a look at the rest of the days here: http://adn.agi.com/GNSSWeb/ Today was special. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 11 August 2013 6:17 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Yes. This week is not the start of a new epoch. On Sun, Aug 11, 2013 at 10:10 AM, Hal Murray wrote: > ma...@non-stop.com.au said: >> Today is start of new epoch. >> As per: http://adn.agi.com/GNSSWeb/ >> 1753:0 Full GPS week since 1st epoch : day of week number >> 729:0 GPS Week since latest epoch : seconds of week at midnight for >> that day > > I don't think so. If this was a new epoch, that 729 would be 0 and > the 1753 would be 2048. > > The 0s above are the day of week and seconds of week, nothing to do > with the epoch. > > > -- > These are my opinions. I hate spam. > > > > ___ > 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. ___ 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. ___ 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.
Re: [time-nuts] Warped back to 1993
But according to Furuno it is a problem: http://www.furuno.com.cy/important-notice.html Important notice to our customers who use FURUNO GPS receivers for marine use that are affected by GPS week number rollover. [eRideOPUS GPS & GNSS receivers are not affected by this matter.] We thank you very much for your trust and continued support. It is regretful to announce that there is a possibility that some of our GPS receivers and GPS-incorporated equipment (please see the list below) may face GPS positioning errors after 11th of August 2013, due to the problem of GPS week number roll-over. Huh?! -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 7:05 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Yep Sorry, I see what you mean, can't be the GPS week rollover bug then. I am at a loss to explain this one then. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 6:33 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Please explain what happened today then? Also, the 2 module that I cannot set to the correct date are both Furino GT-77's. Over on the NTP list they are claiming it's the start of the new GPS 1024 week epoch. If you have a look at the rest of the days here: http://adn.agi.com/GNSSWeb/ Today was special. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 11 August 2013 6:17 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Yes. This week is not the start of a new epoch. On Sun, Aug 11, 2013 at 10:10 AM, Hal Murray wrote: > ma...@non-stop.com.au said: >> Today is start of new epoch. >> As per: http://adn.agi.com/GNSSWeb/ >> 1753:0 Full GPS week since 1st epoch : day of week number >> 729:0 GPS Week since latest epoch : seconds of week at midnight for >> that day > > I don't think so. If this was a new epoch, that 729 would be 0 and > the 1753 would be 2048. > > The 0s above are the day of week and seconds of week, nothing to do > with the epoch. > > > -- > These are my opinions. I hate spam. > > > > ___ > 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. ___ 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. ___ 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.
Re: [time-nuts] Warped back to 1993
Yep Sorry, I see what you mean, can't be the GPS week rollover bug then. I am at a loss to explain this one then. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 6:33 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Please explain what happened today then? Also, the 2 module that I cannot set to the correct date are both Furino GT-77's. Over on the NTP list they are claiming it's the start of the new GPS 1024 week epoch. If you have a look at the rest of the days here: http://adn.agi.com/GNSSWeb/ Today was special. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 11 August 2013 6:17 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Yes. This week is not the start of a new epoch. On Sun, Aug 11, 2013 at 10:10 AM, Hal Murray wrote: > ma...@non-stop.com.au said: >> Today is start of new epoch. >> As per: http://adn.agi.com/GNSSWeb/ >> 1753:0 Full GPS week since 1st epoch : day of week number >> 729:0 GPS Week since latest epoch : seconds of week at midnight for >> that day > > I don't think so. If this was a new epoch, that 729 would be 0 and > the 1753 would be 2048. > > The 0s above are the day of week and seconds of week, nothing to do > with the epoch. > > > -- > These are my opinions. I hate spam. > > > > ___ > 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. ___ 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.
Re: [time-nuts] Warped back to 1993
marki wrote: Today is start of new epoch. I think the next epoch is April 7, 2019 (1024 weeks after the last epoch, August 22, 1999). (Strictly speaking, the epoch is a point in time -- the 1024-week period is an era. Eras begin and end at epochs.) Best regards, Charles ___ 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.
Re: [time-nuts] Warped back to 1993
Please explain what happened today then? Also, the 2 module that I cannot set to the correct date are both Furino GT-77's. Over on the NTP list they are claiming it's the start of the new GPS 1024 week epoch. If you have a look at the rest of the days here: http://adn.agi.com/GNSSWeb/ Today was special. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 11 August 2013 6:17 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Yes. This week is not the start of a new epoch. On Sun, Aug 11, 2013 at 10:10 AM, Hal Murray wrote: > ma...@non-stop.com.au said: >> Today is start of new epoch. >> As per: http://adn.agi.com/GNSSWeb/ >> 1753:0 Full GPS week since 1st epoch : day of week number >> 729:0 GPS Week since latest epoch : seconds of week at midnight for >> that day > > I don't think so. If this was a new epoch, that 729 would be 0 and > the 1753 would be 2048. > > The 0s above are the day of week and seconds of week, nothing to do > with the epoch. > > > -- > These are my opinions. I hate spam. > > > > ___ > 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. ___ 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.
Re: [time-nuts] Warped back to 1993
Yes. This week is not the start of a new epoch. On Sun, Aug 11, 2013 at 10:10 AM, Hal Murray wrote: > ma...@non-stop.com.au said: >> Today is start of new epoch. >> As per: http://adn.agi.com/GNSSWeb/ >> 1753:0 Full GPS week since 1st epoch : day of week number >> 729:0 GPS Week since latest epoch : seconds of week at midnight for >> that day > > I don't think so. If this was a new epoch, that 729 would be 0 and the 1753 > would be 2048. > > The 0s above are the day of week and seconds of week, nothing to do with the > epoch. > > > -- > These are my opinions. I hate spam. > > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
ma...@non-stop.com.au said: > Today is start of new epoch. > As per: http://adn.agi.com/GNSSWeb/ > 1753:0 Full GPS week since 1st epoch : day of week number > 729:0 GPS Week since latest epoch : seconds of week at midnight for > that day I don't think so. If this was a new epoch, that 729 would be 0 and the 1753 would be 2048. The 0s above are the day of week and seconds of week, nothing to do with the epoch. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Warped back to 1993
Today is start of new epoch. As per: http://adn.agi.com/GNSSWeb/ 1753:0 Full GPS week since 1st epoch : day of week number 729:0 GPS Week since latest epoch : seconds of week at midnight for that day So that explains what happened. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 1:19 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Okay this is what worked for me: 1. Removed power and antenna. 2. apply power with no antenna. 3. send :GPS:INIT:DATE 2007,08,11 4. plug antenna back in. For some reason if I used the correct date, the Z3815A warped back to 1993. But I am curious why did this happen today? --marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 1:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Hal, I can't get it to take, I keep getting E-350 and the time does not change. Did you unplug the antenna or anything while you changed date? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 ma...@non-stop.com.au said: > A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's > 26 Dec 1993. > What happened?! ___ Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) There is a week field in the GPS data stream. It's only 10 bits. I had that problem on a Z3801A. It did the right thing after I told it the date. :GPS:INIT:DATE 2011,12,26 -- These are my opinions. I hate spam. ___ 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. ___ 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.
Re: [time-nuts] Warped back to 1993
Nope, I tried all the resets I could find, I can set the date right but as soon as the Z3815A sees a bird, it jumps back to 1993. How annoying, Anyone else with a Z3815A having problems? --marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 2:40 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 I have 5 Z3805A and only one had the wrong date. They all have identical GPS modules and firmware so I don't know why just one decided to warp back to 1993. The Z3815A is still stuck at 1993, I can't even set it to 11 Aug 2007. (-1024) even with antenna unplugged and power cycle. I mean, Can set it to 11 Aug 2007, but after the 1st bird it sees it goes back to 1993. I might try a factory default and see how we go. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joseph Gray Sent: Sunday, 11 August 2013 1:16 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 I just checked by Z3801A which is being monitored by SatStat on an old laptop. Mine is showing the correct date and time. Joe Gray W5JG On Sat, Aug 10, 2013 at 8:53 PM, Hal Murray wrote: > > ma...@non-stop.com.au said: > > A Z3805A, a Z3815A and 58534A integrated timing antenna all think > > it's 26 Dec 1993. > > What happened?! ___ > > Is that off by 1024 weeks? (Looks close, but I haven't checked the > details.) > > There is a week field in the GPS data stream. It's only 10 bits. > > I had that problem on a Z3801A. It did the right thing after I told > it the date. > :GPS:INIT:DATE 2011,12,26 > > > > -- > These are my opinions. I hate spam. > > > > ___ > 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. ___ 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.
Re: [time-nuts] Warped back to 1993
> With the wrong date and time, the GPS should not find almanac data, so will
> not lock.
I don't think that's the right way of describing the problem.
The satellites broadcast on a known frequency, but that gets shifted all over
the place by Doppler. ("All over" means a big shift relative to the
bandwidth of the signal.)
If you have a recent almanac and you know the date/time and location, then
you can compute the Doppler and look in the right frequency and find the
satellites quickly. In this context, "find" means hearing a signal at an
expected frequency. If you don't hear anything where you expect it, then you
get to check nearby frequencies. If you don't find anything nearby, you get
to give up and start searching the whole Doppler range. It's the difference
between warm start and cold start.
Once you do find several satellites, you can figure out the date/time and
location and after a while get a new almanac.
Assume you have done all that. You still don't really know the date. It's
like looking at a clock on the wall. It tells you the time but not the date.
(Or looking at a digital display that tells you the month and day but not
the year.) The GPS signal tells you the date within a 1024 week epoch, but
it doesn't tell you which epoch you are in. Telling it the date has the side
effect of telling it the epoch.
Real early GPS gear punted this problem. There is no way to tell them the
epoch. I don't remember any details, but there have been various discussions
about gear that is now useless. (With some simple post processing, you could
fix that. That's assuming you have a serial interface rather than a
7-segment display.)
--
These are my opinions. I hate spam.
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Re: [time-nuts] Warped back to 1993
I have 5 Z3805A and only one had the wrong date. They all have identical GPS modules and firmware so I don't know why just one decided to warp back to 1993. The Z3815A is still stuck at 1993, I can't even set it to 11 Aug 2007. (-1024) even with antenna unplugged and power cycle. I mean, Can set it to 11 Aug 2007, but after the 1st bird it sees it goes back to 1993. I might try a factory default and see how we go. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joseph Gray Sent: Sunday, 11 August 2013 1:16 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 I just checked by Z3801A which is being monitored by SatStat on an old laptop. Mine is showing the correct date and time. Joe Gray W5JG On Sat, Aug 10, 2013 at 8:53 PM, Hal Murray wrote: > > ma...@non-stop.com.au said: > > A Z3805A, a Z3815A and 58534A integrated timing antenna all think > > it's 26 Dec 1993. > > What happened?! ___ > > Is that off by 1024 weeks? (Looks close, but I haven't checked the > details.) > > There is a week field in the GPS data stream. It's only 10 bits. > > I had that problem on a Z3801A. It did the right thing after I told > it the date. > :GPS:INIT:DATE 2011,12,26 > > > > -- > These are my opinions. I hate spam. > > > > ___ > 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. ___ 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.
Re: [time-nuts] Warped back to 1993
I just checked by Z3801A which is being monitored by SatStat on an old laptop. Mine is showing the correct date and time. Joe Gray W5JG On Sat, Aug 10, 2013 at 8:53 PM, Hal Murray wrote: > > ma...@non-stop.com.au said: > > A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's 26 > > Dec 1993. > > What happened?! ___ > > Is that off by 1024 weeks? (Looks close, but I haven't checked the > details.) > > There is a week field in the GPS data stream. It's only 10 bits. > > I had that problem on a Z3801A. It did the right thing after I told it the > date. > :GPS:INIT:DATE 2011,12,26 > > > > -- > These are my opinions. I hate spam. > > > > ___ > 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.
Re: [time-nuts] Warped back to 1993
With the wrong date and time, the GPS should not find almanac data, so will not lock. This was the problem caused by the 1024 week roll over problem. Are we possibly at week 2048?? 73 Glenn WB4UIV At 11:28 PM 8/10/2013, you wrote: ma...@non-stop.com.au said: > Hal, I can't get it to take, I keep getting E-350 and the time does not > change. Did you unplug the antenna or anything while you changed date? I don't remember doing anything like that, but it was a long time ago. I may have told it the date while it was doing a survey. The text in the Z3801A manual doesn't say anything about the 1024 week problem. It does say "first satellite", so I'd unplug the antenna and power cycle the box and see if that would let you set the date. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Warped back to 1993
ma...@non-stop.com.au said: > Hal, I can't get it to take, I keep getting E-350 and the time does not > change. Did you unplug the antenna or anything while you changed date? I don't remember doing anything like that, but it was a long time ago. I may have told it the date while it was doing a survey. The text in the Z3801A manual doesn't say anything about the 1024 week problem. It does say "first satellite", so I'd unplug the antenna and power cycle the box and see if that would let you set the date. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Warped back to 1993
Okay this is what worked for me: 1. Removed power and antenna. 2. apply power with no antenna. 3. send :GPS:INIT:DATE 2007,08,11 4. plug antenna back in. For some reason if I used the correct date, the Z3815A warped back to 1993. But I am curious why did this happen today? --marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 1:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Hal, I can't get it to take, I keep getting E-350 and the time does not change. Did you unplug the antenna or anything while you changed date? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 ma...@non-stop.com.au said: > A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's > 26 Dec 1993. > What happened?! ___ Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) There is a week field in the GPS data stream. It's only 10 bits. I had that problem on a Z3801A. It did the right thing after I told it the date. :GPS:INIT:DATE 2011,12,26 -- These are my opinions. I hate spam. ___ 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. ___ 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.
Re: [time-nuts] Warped back to 1993
Hal, I can't get it to take, I keep getting E-350 and the time does not change. Did you unplug the antenna or anything while you changed date? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 ma...@non-stop.com.au said: > A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's > 26 Dec 1993. > What happened?! ___ Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) There is a week field in the GPS data stream. It's only 10 bits. I had that problem on a Z3801A. It did the right thing after I told it the date. :GPS:INIT:DATE 2011,12,26 -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Warped back to 1993
ma...@non-stop.com.au said: > A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's 26 > Dec 1993. > What happened?! ___ Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) There is a week field in the GPS data stream. It's only 10 bits. I had that problem on a Z3801A. It did the right thing after I told it the date. :GPS:INIT:DATE 2011,12,26 -- These are my opinions. I hate spam. ___ 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] Warped back to 1993
Some of the GPS clocks think its 26 Dec 1993. A Z3805A, a Z3815A and 58534A integrated timing antenna all think it's 26 Dec 1993. What happened?! ___ 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.
