[time-nuts] GPS week rollover grounds airplanes

[Mark Sims]

Apparently  the rollover grounded some airplanes... oops...

https://arstechnica.com/information-technology/2019/04/gps-rollover-apparently-cause-of-multiple-flight-delays-groundings/
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[time-nuts] GPS week rollover

[Gary Myers]

I thought for sure my Motorola Oncore receiver in my older Tom Clark's
Tac2 would rollover today at 23:59:42 UTC. Using CNS's tac32 software it
took me in to gps week 2048 without a hitch. 

>From the log: 

-> @@Bo - UTC offset = 18 seconds
-> @@Ea,04/07/2019, 00:00:21.000117714, 1.71986531e+008, 

@@Cj

COPYRIGHT 1991-1997 MOTOROLA INC.
SFTW P/N # 98-P36848P 
SOFTWARE VER # 3  
SOFTWARE REV # 1  
SOFTWARE DATE  May 28 1999
MODEL #R5222U1114 
HWDR P/N # 5  
SERIAL #   R0AZUG 
MANUFACTUR DATE 1A30  

Cheers! 

Gary
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Re: [time-nuts] GPS week rollover

[Steve Olney]

Hi Jeff,

On 6/04/2019 3:30 pm, Jeff Zambory wrote:

Yes Steve, you are correct.

https://www.gps.gov/

Scroll down a bit and you can find a count down to the roll over. And it states 
the time when it will roll over. Just what you have said.


Thanks !!!

I'll watch that and watch my receivers.

It seems, from posts here, that different receivers exhibit different 
WNRO behaviour - with effects noted *before* the RO epoch.


I am curious about this and set my Garmin 16x to output as per a 
snapshot below...


$PGRMF,1023,590391,060419,195933,18

...which is GPS week, GPS seconds, UTC date, UTC time and leap second count

As GPS seconds wraps around at 604799 (and GPS is incremented at that 
moment) then there is 604799 + 1 - 590391 = 14409 seconds to go from 
19:59:33.


14408 seconds = 4 h 9 seconds.   19:59:33 + 4:00:09 = 23:59:42.

This agrees with the www.gps.gov data.

So why are people reporting effects already ? My *guess* as to why some 
receivers have reacted before the RO epoch is that attempts to address 
the issue have been different depending on the vintage of the GPS receivers.


 * Receivers manufactured just a few years before the first rollover
   data would need to cross the 1023 - 0 week boundary a short-ish time
   after manufacture.   So some kind of offset would need to be added
   to the week number.  These units which have not had firmware updates
   would presumably react early to the second rollover depending on the
   date of manufacture.
 * Receivers manufactured after the first rollover would presumably
   react late to the second RO by the same logic.
 * Receivers of any manufacture date which has had its firmware updated
   regularly would presumably not be affected as the updates would keep
   pushing the internal wrap around epoch further into the future.
 * Old receivers (like my GPS 35 with no updates) already have gone
   through one rollover (currently showing 21 August 1999) and will
   presumably go back to 1980 dates with this rollover.

So - my bottom-line note to myself about this is that just because a 
receiver looks fine tomorrow doesn't mean it won't fall over next week, 
or next month, or next year, etc.


Cheers

Steve

P.S. for some reason time-nut posts arrive in my inbox uncorrelated to 
their time stamps.  So I find myself replying to later posts before 
earlier ones.  Gets a bit confusing for this Senior Citizen... LOL...


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Re: [time-nuts] GPS week rollover

[Mike Cook]

> Le 6 avr. 2019 à 17:53, jimlux  a écrit :
> 
> On 4/6/19 12:53 AM, Mike Cook wrote:
>> The OP doesn’t state where he got the  « quote » from, but IMHO it is wrong. 
>> As I understand it.
>> The GPS epoch started at 0h 1st June 1980
> 
> 6 Jan 1980 00:00:00 UTC

Just so… 01/06  tripped me

> 
> 
> 
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Benjimin Franklin


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Re: [time-nuts] GPS week rollover

[jimlux]

On 4/6/19 12:53 AM, Mike Cook wrote:

The OP doesn’t state where he got the  « quote » from, but IMHO it is wrong. As 
I understand it.
The GPS epoch started at 0h 1st June 1980


6 Jan 1980 00:00:00 UTC



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Re: [time-nuts] GPS week rollover

[Martin Burnicki]

Steve Olney wrote:
> Just curious - WNRO is not an issue for me even if my GPS receivers are
> affected - but I note that the time of rollover is being quoted as
> 23:59:59 UTC 6th April.
> 
> Wouldn't the time actually be 18 seconds earlier ? - i.e., 23:59:42 -
> due to leap seconds ?
> 
> BTW - I'm not clear about GPS time vs UTC (which is probably relevant to
> the above).  Any pointers to a clear explanation ?

The explanation is simple, IMO.

When the GPS system was put into operation in 1980 then the GPS time
matched UTC.

However, a number of leap seconds have been inserted into the UTC time
scale since, and each leap second delayed UTC by 1 s.

Yet 18 leap seconds have been inserted, so UTC is 18 s behind GPS time,
or the other way round, GPS time is 18 s ahead of UTC, so the WNRO
occurs 18 s before UTC midnight.

BTW, the effects of the rollover have already begun. For example, the
reference times of the almanac and clock correction parameters in the
the navigation messages received from the satellites refer to a time a
in the near future, so the week number of those time stamps has already
rolled over.

Martin

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Re: [time-nuts] GPS week rollover

[Steve Olney]

Hi Martin,

On 6/04/2019 6:44 pm, Martin Burnicki wrote:

Steve Olney wrote:

Wouldn't the time actually be 18 seconds earlier ? - i.e., 23:59:42 -
due to leap seconds ?


Martin Burnicki wrote:

so the WNRO
occurs 18 s before UTC midnight.


So - yes.

Thanks for the clarification.

Cheers

Steve


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Re: [time-nuts] GPS week rollover

[Mike Cook]

The OP doesn’t state where he got the  « quote » from, but IMHO it is wrong. As 
I understand it.
The GPS epoch started at 0h 1st June 1980 and the week number roles at 1024 
week intervals at 0h GPS time. When a leap second is added its as if the clock 
stops for a second so GPS time will be in advance of UTC buy the number of leap 
seconds added.  18 leap seconds have been added to date, so 0h GPS 07 april 
2019 will be crossed at 23:59:42 UTC on April 6 as you indicated.


> Le 6 avr. 2019 à 00:40, Steve Olney  a écrit :
> 
> Just curious - WNRO is not an issue for me even if my GPS receivers are 
> affected - but I note that the time of rollover is being quoted as 23:59:59 
> UTC 6th April.
> 
> Wouldn't the time actually be 18 seconds earlier ? - i.e., 23:59:42 - due to 
> leap seconds ?
> 
> BTW - I'm not clear about GPS time vs UTC (which is probably relevant to the 
> above).  Any pointers to a clear explanation ?
> 
> Cheers
> 
> Steve
> 
> 
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"Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une 
petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
Benjimin Franklin


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Re: [time-nuts] GPS week rollover

[Mike Cook]

I checked my Garmin Emap, 1999 vintage IIRC. That is telling me that it is 
20/05/2014. 

I found this for Trimble which shows a number of devices affected by this which 
are commonly used bt timenuts.



Have a nice day

> Le 28 mars 2019 à 20:21, Steve - Home  a écrit :
> 
> I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 18 
> seconds ahead of a Motorola 12 channel (and my iPhone). I haven’t had time to 
> look into it as I’m adjusting to “voluntary” retirement and trying to clear 
> out some excess stuff. 
> 
> Steve
> 
> 
> 
> 
>> On Mar 28, 2019, at 1:30 PM,   wrote:
>> 
>> Are we expecting any week rollover problems with the receivers we time
>> nuts like to play with???
>> 
>> Cheers,
>> 
>> Corby
>> 
>> 
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"Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une 
petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
Benjimin Franklin


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Re: [time-nuts] GPS week rollover

[Jeff Zambory]

Yes Steve, you are correct. 

https://www.gps.gov/

Scroll down a bit and you can find a count down to the roll over. And it states 
the time when it will roll over. Just what you have said. 

Jeff Z. 

Sent from my iPhone

> On Apr 5, 2019, at 4:40 PM, Steve Olney  wrote:
> 
> Just curious - WNRO is not an issue for me even if my GPS receivers are 
> affected - but I note that the time of rollover is being quoted as 23:59:59 
> UTC 6th April.
> 
> Wouldn't the time actually be 18 seconds earlier ? - i.e., 23:59:42 - due to 
> leap seconds ?
> 
> BTW - I'm not clear about GPS time vs UTC (which is probably relevant to the 
> above).  Any pointers to a clear explanation ?
> 
> Cheers
> 
> Steve
> 
> 
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Re: [time-nuts] GPS week rollover

[Steve Olney]

Just curious - WNRO is not an issue for me even if my GPS receivers are 
affected - but I note that the time of rollover is being quoted as 
23:59:59 UTC 6th April.


Wouldn't the time actually be 18 seconds earlier ? - i.e., 23:59:42 - 
due to leap seconds ?


BTW - I'm not clear about GPS time vs UTC (which is probably relevant to 
the above).  Any pointers to a clear explanation ?


Cheers

Steve


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Re: [time-nuts] GPS week rollover

[EB4APL]

I received the same invitation. And they states that the WNRO problem is 
an "external" problem.  I did it and now all the maps are signaled as 
invalid!


Fortunately I was able to copy my  main map from a backup copy.

Regards,

Ignacio EB4APL


El 04/04/2019 a las 12:29, Mike Cook escribió:

Hi,
   I just got a heads up fro TomTom, saying my Go Live 825 bought 2012 « may » 
have WNRO problems after the April 6 rollover and invited me to update the 
firmware. I wouldn’t think it would affect the navigation, but it might brick 
the device. Unfortunately I can’t test it as it went to recycle 3 month ago . 
This could be an interesting week.
Mike



---
El software de antivirus Avast ha analizado este correo electrónico en busca de 
virus.
https://www.avast.com/antivirus


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Re: [time-nuts] GPS week rollover

[Dr Geophysics]

Potentially everything using the week 10 bits.   Check your manufacturer.   
Trimble is all over this. 

Sent from my iPhone

> On Apr 4, 2019, at 06:29, Mike Cook  wrote:
> 
> Hi,
>  I just got a heads up fro TomTom, saying my Go Live 825 bought 2012 « may » 
> have WNRO problems after the April 6 rollover and invited me to update the 
> firmware. I wouldn’t think it would affect the navigation, but it might brick 
> the device. Unfortunately I can’t test it as it went to recycle 3 month ago . 
> This could be an interesting week.
> Mike
> 
>> Le 28 mars 2019 à 20:21, Steve - Home  a écrit :
>> 
>> I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 
>> 18 seconds ahead of a Motorola 12 channel (and my iPhone). I haven’t had 
>> time to look into it as I’m adjusting to “voluntary” retirement and trying 
>> to clear out some excess stuff. 
>> 
>> Steve
>> 
>> 
>> 
>> 
>>> On Mar 28, 2019, at 1:30 PM,   wrote:
>>> 
>>> Are we expecting any week rollover problems with the receivers we time
>>> nuts like to play with???
>>> 
>>> Cheers,
>>> 
>>> Corby
>>> 
>>> 
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>> 
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> 
> "Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une 
> petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
> Benjimin Franklin
> 
> 
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Re: [time-nuts] GPS week rollover

[Mike Cook]

Hi,
  I just got a heads up fro TomTom, saying my Go Live 825 bought 2012 « may » 
have WNRO problems after the April 6 rollover and invited me to update the 
firmware. I wouldn’t think it would affect the navigation, but it might brick 
the device. Unfortunately I can’t test it as it went to recycle 3 month ago . 
This could be an interesting week.
Mike

> Le 28 mars 2019 à 20:21, Steve - Home  a écrit :
> 
> I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 18 
> seconds ahead of a Motorola 12 channel (and my iPhone). I haven’t had time to 
> look into it as I’m adjusting to “voluntary” retirement and trying to clear 
> out some excess stuff. 
> 
> Steve
> 
> 
> 
> 
>> On Mar 28, 2019, at 1:30 PM,   wrote:
>> 
>> Are we expecting any week rollover problems with the receivers we time
>> nuts like to play with???
>> 
>> Cheers,
>> 
>> Corby
>> 
>> 
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> 
> 
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"Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une 
petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
Benjimin Franklin


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Re: [time-nuts] GPS week rollover

[Bob kb8tq]

Hi

If you want it to behave like a signal generator ( variable output level) that 
also is
another rabbit hole to run down. Since the signals are well below the noise 
after
full spreading (and not all that strong before spreading) it takes some care to 
get
that right. On a production basis, testing sensitivity *might* be something you 
would
want to do…..

There *is* the good old “hook up an antenna and see if it works” approach. In 
an era 
where not all systems are visible from all parts of the world (or are not yet 
launched) 
that has some limits ….

Bob

> On Mar 29, 2019, at 9:46 PM, jimlux  wrote:
> 
> On 3/29/19 12:22 PM, John C. Westmoreland, P.E. wrote:
>> To All:
>> I have a related question; hope it's OK:
>> What are these companies using for their "GPS Simulation/Simulators?".
>> Is it actually simulating the RF downlink or is a direct data stream
>> injection into a tap into the receiver??
> 
> RF.
> GPS simulators, recorders, players are a standard thing.
> 
> They range in complexity - some generate the entire sequence "offline" and 
> store it in a big memory, then just play it back. Others can run it in real 
> time and take dynamic inputs (e.g. from a simulated airplane flight).  Some 
> have variable levels.
> 
> The tricky parts are:
> you have to do Doppler too, so it's not just hooking up 1 Mchip/sec PN codes 
> to a mixer and a 1575.42 MHz oscillator.   That said, because many receivers 
> use 1 or 2 bit digitizers, you can make some shortcuts.
> 
> The recorder/playback ones are the simplest - they are literally a 1 bit 
> thresholder running at a suitable rate hooked up to a LNA and the playback 
> plays back the 1 bit through the same filter, and trusts in the harmonics 
> coming through.
> 
> The fancy ones (Spirent is one mfr) are very nice - they're basically a real 
> time waveform generator with a bunch of software, implemented in an FPGA - 
> they can do hundreds of satellites on multiple frequencies, with multipath, 
> relativistic effects, etc.  (Like many software defined widgets, you pay to 
> "unlock" various features).
> 
> 
> 
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Re: [time-nuts] GPS week rollover

[jimlux]

On 3/29/19 12:22 PM, John C. Westmoreland, P.E. wrote:

To All:

I have a related question; hope it's OK:

What are these companies using for their "GPS Simulation/Simulators?".

Is it actually simulating the RF downlink or is a direct data stream
injection into a tap into the receiver??



RF.
GPS simulators, recorders, players are a standard thing.

They range in complexity - some generate the entire sequence "offline" 
and store it in a big memory, then just play it back. Others can run it 
in real time and take dynamic inputs (e.g. from a simulated airplane 
flight).  Some have variable levels.


The tricky parts are:
you have to do Doppler too, so it's not just hooking up 1 Mchip/sec PN 
codes to a mixer and a 1575.42 MHz oscillator.   That said, because many 
receivers use 1 or 2 bit digitizers, you can make some shortcuts.


The recorder/playback ones are the simplest - they are literally a 1 bit 
thresholder running at a suitable rate hooked up to a LNA and the 
playback plays back the 1 bit through the same filter, and trusts in the 
harmonics coming through.


The fancy ones (Spirent is one mfr) are very nice - they're basically a 
real time waveform generator with a bunch of software, implemented in an 
FPGA - they can do hundreds of satellites on multiple frequencies, with 
multipath, relativistic effects, etc.  (Like many software defined 
widgets, you pay to "unlock" various features).




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Re: [time-nuts] GPS week rollover

[Michael Wouters]

A multichannel, L1 GPS-only simulator/recorder costs about US5k. We have
one of these that we used to test for rollover problems with some older
receivers that we use (none found). The software with this lower cost
device is not very sophisticated. As Bob hints though, a top of the line
simulator is very expensive, about us200k, the last time I asked.


On Sat, 30 Mar 2019 at 8:00 am, Bob kb8tq  wrote:

> Hi
>
> Obviously the real answer is going to be “that depends”.
>
> Back when I worked for a living, we had an HP generator that would “play
> back” a recorded ~ 30 minute
> set of GPS “full sky” observations. It was strictly a playback with no
> real way to tweak this or that. We also
> had a single channel device that could be set to do just about anything
> (but only a single channel / sat). The
> “full sky” gizmo is fine for things like sensitivity. The single channel
> device is of more use for poking at rollover
> issues.
>
> Indeed if you have the budget, you can get a setup that will let you run
> multiple sat systems with a dozen sats
> on each system at any simulated location,  time, signal level, errors …...
> Last time I priced one … .yikes ….. I don’t
> know of anybody doing timing with that sort of setup.
>
> Bob
>
> > On Mar 29, 2019, at 3:22 PM, John C. Westmoreland, P.E. <
> j...@westmorelandengineering.com> wrote:
> >
> > To All:
> >
> > I have a related question; hope it's OK:
> >
> > What are these companies using for their "GPS Simulation/Simulators?".
> >
> > Is it actually simulating the RF downlink or is a direct data stream
> > injection into a tap into the receiver??
> >
> > Thanks In Advance,
> > John W.
> >
> >
> > On Fri, Mar 29, 2019 at 11:00 AM Michael Shields via time-nuts <
> > time-nuts@lists.febo.com> wrote:
> >
> >> Avidyne avionics are known to be affected by the rollover, causing the
> >> loss of some displayed data.
> >>
> >> https://www.avidyne.com/files/downloads/606-00182-019.pdf
> >>
> >>
> >> On Thu, Mar 28, 2019 at 3:04 PM Mark Sims  wrote:
> >>>
> >>> I doubt that any GPS receivers will be newly affected on April 6.
>  Some
> >> very early receivers were hit on the first GPS rollover, but those made
> >> since then usually have a 1024 week compensation built in based upon the
> >> firmware creation date.  Those rollover 1024 weeks from that date and
> start
> >> sending incorrect dates at other places in the 1024 week cycle.  Some
> >> receivers even let you force the rollover week.
> >>>
>  I have a Z3816A that’s showing a yellow “ro” next to the date in LH
> >> and is 18 seconds ahead of a Motorola 12 channel
> >>>
> >>> If Lady Heather sees a date earlier than a set year (currently 2017),
> it
> >> assumes the GPS device has rollover issues and adds 1024 weeks to
> correct
> >> the date and shows the "ro" flag.
> >>>
> >>> As far as the 18 second time difference, one of the devices is
> >> configured to show GPS time and the other is set for UTC time.  At the
> top
> >> right corner of the screen it should say either "UTC time OK" or "GPS
> time
> >> OK" (as long as the device has a valid time).  The TG and TU commands
> can
> >> switch between GPS and UTC time displays.  Some receivers have firmware
> >> commands to switch between the two.  For the others, Heather does the
> >> conversion in software using the "UTC offset" (i.e. leapsecond count)
> >> value.  Many receivers send this offset.   If it does not, the user can
> set
> >> the value.  And if no value is available Heather makes a best guess as
> to
> >> what the value might be (and shows it in RED).  The guessed value is
> rather
> >> prone to errors, but is better than nothing.
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Re: [time-nuts] GPS week rollover

[Bob kb8tq]

Hi

Obviously the real answer is going to be “that depends”. 

Back when I worked for a living, we had an HP generator that would “play back” 
a recorded ~ 30 minute 
set of GPS “full sky” observations. It was strictly a playback with no real way 
to tweak this or that. We also 
had a single channel device that could be set to do just about anything (but 
only a single channel / sat). The 
“full sky” gizmo is fine for things like sensitivity. The single channel device 
is of more use for poking at rollover 
issues. 

Indeed if you have the budget, you can get a setup that will let you run 
multiple sat systems with a dozen sats 
on each system at any simulated location,  time, signal level, errors …... Last 
time I priced one … .yikes ….. I don’t 
know of anybody doing timing with that sort of setup. 

Bob 

> On Mar 29, 2019, at 3:22 PM, John C. Westmoreland, P.E. 
>  wrote:
> 
> To All:
> 
> I have a related question; hope it's OK:
> 
> What are these companies using for their "GPS Simulation/Simulators?".
> 
> Is it actually simulating the RF downlink or is a direct data stream
> injection into a tap into the receiver??
> 
> Thanks In Advance,
> John W.
> 
> 
> On Fri, Mar 29, 2019 at 11:00 AM Michael Shields via time-nuts <
> time-nuts@lists.febo.com> wrote:
> 
>> Avidyne avionics are known to be affected by the rollover, causing the
>> loss of some displayed data.
>> 
>> https://www.avidyne.com/files/downloads/606-00182-019.pdf
>> 
>> 
>> On Thu, Mar 28, 2019 at 3:04 PM Mark Sims  wrote:
>>> 
>>> I doubt that any GPS receivers will be newly affected on April 6.   Some
>> very early receivers were hit on the first GPS rollover, but those made
>> since then usually have a 1024 week compensation built in based upon the
>> firmware creation date.  Those rollover 1024 weeks from that date and start
>> sending incorrect dates at other places in the 1024 week cycle.  Some
>> receivers even let you force the rollover week.
>>> 
 I have a Z3816A that’s showing a yellow “ro” next to the date in LH
>> and is 18 seconds ahead of a Motorola 12 channel
>>> 
>>> If Lady Heather sees a date earlier than a set year (currently 2017), it
>> assumes the GPS device has rollover issues and adds 1024 weeks to correct
>> the date and shows the "ro" flag.
>>> 
>>> As far as the 18 second time difference, one of the devices is
>> configured to show GPS time and the other is set for UTC time.  At the top
>> right corner of the screen it should say either "UTC time OK" or "GPS time
>> OK" (as long as the device has a valid time).  The TG and TU commands can
>> switch between GPS and UTC time displays.  Some receivers have firmware
>> commands to switch between the two.  For the others, Heather does the
>> conversion in software using the "UTC offset" (i.e. leapsecond count)
>> value.  Many receivers send this offset.   If it does not, the user can set
>> the value.  And if no value is available Heather makes a best guess as to
>> what the value might be (and shows it in RED).  The guessed value is rather
>> prone to errors, but is better than nothing.
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Re: [time-nuts] GPS week rollover

[John C. Westmoreland, P.E.]

To All:

I have a related question; hope it's OK:

What are these companies using for their "GPS Simulation/Simulators?".

Is it actually simulating the RF downlink or is a direct data stream
injection into a tap into the receiver??

Thanks In Advance,
John W.


On Fri, Mar 29, 2019 at 11:00 AM Michael Shields via time-nuts <
time-nuts@lists.febo.com> wrote:

> Avidyne avionics are known to be affected by the rollover, causing the
> loss of some displayed data.
>
> https://www.avidyne.com/files/downloads/606-00182-019.pdf
>
>
> On Thu, Mar 28, 2019 at 3:04 PM Mark Sims  wrote:
> >
> > I doubt that any GPS receivers will be newly affected on April 6.   Some
> very early receivers were hit on the first GPS rollover, but those made
> since then usually have a 1024 week compensation built in based upon the
> firmware creation date.  Those rollover 1024 weeks from that date and start
> sending incorrect dates at other places in the 1024 week cycle.  Some
> receivers even let you force the rollover week.
> >
> > > I have a Z3816A that’s showing a yellow “ro” next to the date in LH
> and is 18 seconds ahead of a Motorola 12 channel
> >
> > If Lady Heather sees a date earlier than a set year (currently 2017), it
> assumes the GPS device has rollover issues and adds 1024 weeks to correct
> the date and shows the "ro" flag.
> >
> > As far as the 18 second time difference, one of the devices is
> configured to show GPS time and the other is set for UTC time.  At the top
> right corner of the screen it should say either "UTC time OK" or "GPS time
> OK" (as long as the device has a valid time).  The TG and TU commands can
> switch between GPS and UTC time displays.  Some receivers have firmware
> commands to switch between the two.  For the others, Heather does the
> conversion in software using the "UTC offset" (i.e. leapsecond count)
> value.  Many receivers send this offset.   If it does not, the user can set
> the value.  And if no value is available Heather makes a best guess as to
> what the value might be (and shows it in RED).  The guessed value is rather
> prone to errors, but is better than nothing.
> > ___
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> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
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Re: [time-nuts] GPS week rollover

[Michael Shields via time-nuts]

Avidyne avionics are known to be affected by the rollover, causing the
loss of some displayed data.

https://www.avidyne.com/files/downloads/606-00182-019.pdf


On Thu, Mar 28, 2019 at 3:04 PM Mark Sims  wrote:
>
> I doubt that any GPS receivers will be newly affected on April 6.   Some very 
> early receivers were hit on the first GPS rollover, but those made since then 
> usually have a 1024 week compensation built in based upon the firmware 
> creation date.  Those rollover 1024 weeks from that date and start sending 
> incorrect dates at other places in the 1024 week cycle.  Some receivers even 
> let you force the rollover week.
>
> > I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 
> > 18 seconds ahead of a Motorola 12 channel
>
> If Lady Heather sees a date earlier than a set year (currently 2017), it 
> assumes the GPS device has rollover issues and adds 1024 weeks to correct the 
> date and shows the "ro" flag.
>
> As far as the 18 second time difference, one of the devices is configured to 
> show GPS time and the other is set for UTC time.  At the top right corner of 
> the screen it should say either "UTC time OK" or "GPS time OK" (as long as 
> the device has a valid time).  The TG and TU commands can switch between GPS 
> and UTC time displays.  Some receivers have firmware commands to switch 
> between the two.  For the others, Heather does the conversion in software 
> using the "UTC offset" (i.e. leapsecond count) value.  Many receivers send 
> this offset.   If it does not, the user can set the value.  And if no value 
> is available Heather makes a best guess as to what the value might be (and 
> shows it in RED).  The guessed value is rather prone to errors, but is better 
> than nothing.
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> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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Re: [time-nuts] GPS week rollover

[Martin Burnicki]

Martin Burnicki wrote:
> Gary E. Miller wrote:
>> Telit has already issued an App note on this.  They tested their
>> GPS with a GPS simulator.  One of their common models will fail on
>> April 6. Two more will fail in November.
>>
>> Sorry, I can't find it online.
> 
> I found an overview here:
> https://rutronik-tec.com/gps-week-rollover-2019/telit-cellular-gps-combo-solutions/

Oops, that should have been
https://rutronik-tec.com/gps-week-rollover-2019/

> which contains links to related PDFs, e.g.:
> https://rutronik-tec.com/wp-content/uploads/2019/02/Telit-Cellular-GPS-Combo-Solutions.pdf

Martin

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Re: [time-nuts] GPS week rollover

[Martin Burnicki]

Gary E. Miller wrote:
> Yo Mark!
> 
> On Thu, 28 Mar 2019 20:38:42 + Mark Sims 
> wrote:
> 
>> I doubt that any GPS receivers will be newly affected on April
>> 6.
> 
> Telit has already issued an App note on this.  They tested their
> GPS with a GPS simulator.  One of their common models will fail on
> April 6. Two more will fail in November.
> 
> Sorry, I can't find it online.

I found an overview here:
https://rutronik-tec.com/gps-week-rollover-2019/telit-cellular-gps-combo-solutions/

which contains links to related PDFs, e.g.:
https://rutronik-tec.com/wp-content/uploads/2019/02/Telit-Cellular-GPS-Combo-Solutions.pdf

Martin

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Re: [time-nuts] GPS week rollover

[Björn]

Sent from my iPhone

> On 28 Mar 2019, at 23:45, Gary E. Miller  wrote:
> 
> Yo Mark!
> 
> On Thu, 28 Mar 2019 20:38:42 +
> Mark Sims  wrote:
> 
>> I doubt that any GPS receivers will be newly affected on April 6.
> 
> Telit has already issued an App note on this.  They tested their GPS
> with a GPS simulator.  One of their common models will fail on April 6.
> Two more will fail in November.
> 
> Sorry, I can't find it online.
> 
> I know because a well known self driving car company contacted me after
> they discovered a large number of their cars are affected.

Thats a bit strange considering the timeframes involved. Would have imagined 
that the self driving company bought units within say the last five years... 
why would the GPS vendor sell receivers that will fail for this reason so soon 
after purchase?

/Björn 

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Re: [time-nuts] GPS week rollover

[Gary E. Miller]

Yo Mark!

On Thu, 28 Mar 2019 20:38:42 +
Mark Sims  wrote:

> I doubt that any GPS receivers will be newly affected on April 6.

Telit has already issued an App note on this.  They tested their GPS
with a GPS simulator.  One of their common models will fail on April 6.
Two more will fail in November.

Sorry, I can't find it online.

I know because a well known self driving car company contacted me after
they discovered a large number of their cars are affected.

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

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


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[time-nuts] GPS week rollover

[Mark Sims]

I doubt that any GPS receivers will be newly affected on April 6.   Some very 
early receivers were hit on the first GPS rollover, but those made since then 
usually have a 1024 week compensation built in based upon the firmware creation 
date.  Those rollover 1024 weeks from that date and start sending incorrect 
dates at other places in the 1024 week cycle.  Some receivers even let you 
force the rollover week.

> I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 18 
> seconds ahead of a Motorola 12 channel

If Lady Heather sees a date earlier than a set year (currently 2017), it 
assumes the GPS device has rollover issues and adds 1024 weeks to correct the 
date and shows the "ro" flag.

As far as the 18 second time difference, one of the devices is configured to 
show GPS time and the other is set for UTC time.  At the top right corner of 
the screen it should say either "UTC time OK" or "GPS time OK" (as long as the 
device has a valid time).  The TG and TU commands can switch between GPS and 
UTC time displays.  Some receivers have firmware commands to switch between the 
two.  For the others, Heather does the conversion in software using the "UTC 
offset" (i.e. leapsecond count) value.  Many receivers send this offset.   If 
it does not, the user can set the value.  And if no value is available Heather 
makes a best guess as to what the value might be (and shows it in RED).  The 
guessed value is rather prone to errors, but is better than nothing.
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Re: [time-nuts] GPS week rollover

[Steve - Home]

I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 18 
seconds ahead of a Motorola 12 channel (and my iPhone). I haven’t had time to 
look into it as I’m adjusting to “voluntary” retirement and trying to clear out 
some excess stuff. 

Steve




> On Mar 28, 2019, at 1:30 PM,   wrote:
> 
> Are we expecting any week rollover problems with the receivers we time
> nuts like to play with???
> 
> Cheers,
> 
> Corby
> 
> 
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[time-nuts] GPS week rollover

[cdelect]

Are we expecting any week rollover problems with the receivers we time
nuts like to play with???

Cheers,

Corby


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