Re: Time question on GPS TIME and leap second.

[rodwall1...@gmail.com]

Thanks to all who replied to my questions about the time on GPS.
The reason I asked about the leap second. Is if the following analog clock GPS 
driver included the leap second correction.

Yes it would.

http://www.altronics.com.au/p/k1129-gps-synchronised-clock-kit/

It also corrects it for daylight saving.

Thanks all,

Roderick Wall.

- Reply message -
From: "Brooke Clarke" 
To: "sundial list" 
Subject: Time question on GPS TIME and leap second.
Date: Tue, Jan 31, 2017 7:29 AM

Hi Roderick:

GPS time is continuous, that's to say there are no leap seconds or other 
changes to it since it started.  It uses a 10 
bit binary week counter so the week number rolls over after 1024 weeks.  This 
causes problems for GPS receivers that are 
more than a few years old since they have no idea what year it is.
The total number of seconds offset from UTC is transmitted separately so that a 
GPS receiver can display either GPS time 
or UTC.
Note that the time and position are independent from the year.

http://www.prc68.com/I/Trimpack.shtml#WkRlvr

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 
> Hi all,
>
> Was just listening to the CrowdScience on time. Thanks to whoever posted the 
> link to it.
>
> CrowdScience indicated that a leap second was not added for the GPS. They 
> also indicated that the GPS gives us UTC time.
>
> Question:
> The UTC time that the GPS gives. Does that have the leap second added?
>
> Thanks,
>
> Regards,
>
> Roderick Wall.
>
> - Reply message -
> From: "Michael Ossipoff" 
> To: "Robert Kellogg" 
> Cc: "sundial list" 
> Subject: Why we should reform the Calendar
> Date: Mon, Jan 30, 2017 8:00 AM
>
> On Sun, Jan 29, 2017 at 2:41 PM, Robert Kellogg 
> wrote:
>
> > Michael goes off looking for the ideal tropical year
>
>
> There isn't an "ideal tropical year", but, as a choice for a
> leapyear-rule's mean-year, the length of the mean tropical year (MTY) is
> best for year-round reduction of longterm calendar-drift.  ...and the
> average of the lengths of the March & September Equinox tropical years
> (I'll call that the Average Equinox Year (AEY) ) is a compromise between
> the vernal equinoxes of the North & the South.
>
>
> > , perhaps ignoring effects of the earth's nutations.
> >
>
> Of course. The nutations are small in amplitude & period. They aren't part
> of calendar rules. The mean equinox (nutations averaged-out) is the one
> that is meant when the equinox is spoken of with regard to calendars.
>
>
>
> > I'll still take the one of 1900, most importantly because it defines the
> > SI second.
>
>
> The SI second was defined as 1/86,400 of a mean solar day, for some year in
> the early 19th century. I don't remember exactly what year that was. 1820?
> 1840? 1850?
>
> Evidently it isn't practical to update the length of the SI second, but
> that doesn't mean that calendars have to be based on the ephemeris day, or
> atomic day, consisting of 86,400 SI seconds, when that's known to be
> different from today's mean solar day.
>
> That's why I suggest 365.24217 instead of 365.24219 for the length of the
> mean tropical year (MTYI. It makes sense to base a calendar leap-year
> rule's mean-year on the actual length of a tropical-year (whichever one we
> want to use) on the length of that tropical year in* today's* mean days.
>
>
> >
> >
> > So, contemplating changing the year is non trivial.
>
>
> Evidently there must be some reason why it would be impractical to update
> the length of the SI second. But it isn't necessary to call a MTY 365.24219
> days, when it's really 365.24217 mean days long.   ...for the purposes of a
> calendar leapyear rule. There's inevitable inaccuracy due to rounding-off,
> and due to gradual change in the lengths of all the tropical years,
> including the MTY. But that doesn't mean we have to intentionally add
> avoidable error.
>
>
>
> > Contemplating decoupling UTC from the rotation of the earth (ie necessity
> > of being within .9 sec of UT1) likewise has significant consequences.
> > Let's let the IAU chart the future of time.
>
>
> Sure, but it isn't necessary to base a calendar on a day that isn't today's
> mean solar day.
>
> Michael Ossipoff
>
>
>
>
>
> > Dennis and Ken, if you're listening to this discussion, please chime in.
> >
> >
> > On 1/29/2017 12:27 PM, sundial-requ...@uni-koeln.de wrote:
> >
> >> Send sundial mailing list submissions to
> >> sundial@uni-koeln.de
> >>
> >> To subscribe or unsubscribe via the World Wide Web, visit
> >>https://lists.uni-koeln.de/mailman/listinfo/sundial
> >> or, via email, send a message with subject or body 'help' to
> >> sundial-requ...@uni-koeln.de
> >>
> >> You can reach the person managing the list at
> >> sundial-ow...@uni-koeln.de
> >>
> >> When 

Re: Time question on GPS TIME and leap second.

[rodwall1...@gmail.com]

A recent article on the GPS analog clock driver. A better description;
http://archive.siliconchip.com.au/cms/A_92/article.html

Roderick Wall.

- Reply message -
From: "Richard Langley" 
To: "Brooke Clarke" , "sundial list" 
Subject: Time question on GPS TIME and leap second.
Date: Tue, Jan 31, 2017 10:33 AM

"This causes problems for GPS receivers that are more than a few years old 
since they have no idea what year it is."


Not quite true. One of the continuously operating receivers at UNB is more than 
15 years old. Please see:

http://gauss2.gge.unb.ca/gpsworld/gpsworld.november98.pdf​


-- Richard Langley


-
| Richard B. LangleyE-mail: l...@unb.ca |
| Geodetic Research Laboratory  Web: 
http://gge.unb.ca  |
| Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142   |
| University of New Brunswick   Fax:  +1 506 453-4943   |
| Fredericton, N.B., Canada  E3B 5A3|
|Fredericton?  Where's that?  See: 
http://www.fredericton.ca/
   |
-

From: sundial  on behalf of Brooke Clarke 

Sent: Monday, January 30, 2017 4:29 PM
To: sundial list
Subject: Re: Time question on GPS TIME and leap second.

Hi Roderick:

GPS time is continuous, that's to say there are no leap seconds or other 
changes to it since it started.  It uses a 10 bit binary week counter so the 
week number rolls over after 1024 weeks.  This causes problems for GPS 
receivers that are more than a few years old since they have no idea what year 
it is.
The total number of seconds offset from UTC is transmitted separately so that a 
GPS receiver can display either GPS time or UTC.
Note that the time and position are independent from the year.

http://www.prc68.com/I/Trimpack.shtml#WkRlvr

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html


 Original Message 
Hi all,

Was just listening to the CrowdScience on time. Thanks to whoever posted the 
link to it.

CrowdScience indicated that a leap second was not added for the GPS. They also 
indicated that the GPS gives us UTC time.

Question:
The UTC time that the GPS gives. Does that have the leap second added?

Thanks,

Regards,

Roderick Wall.

- Reply message -
From: "Michael Ossipoff" 
To: "Robert Kellogg" 
Cc: "sundial list" 
Subject: Why we should reform the Calendar
Date: Mon, Jan 30, 2017 8:00 AM


On Sun, Jan 29, 2017 at 2:41 PM, Robert Kellogg 

wrote:

> Michael goes off looking for the ideal tropical year


There isn't an "ideal tropical year", but, as a choice for a
leapyear-rule's mean-year, the length of the mean tropical year (MTY) is
best for year-round reduction of longterm calendar-drift.  ...and the
average of the lengths of the March & September Equinox tropical years
(I'll call that the Average Equinox Year (AEY) ) is a compromise between
the vernal equinoxes of the North & the South.


> , perhaps ignoring effects of the earth's nutations.
>

Of course. The nutations are small in amplitude & period. They aren't part
of calendar rules. The mean equinox (nutations averaged-out) is the one
that is meant when the equinox is spoken of with regard to calendars.



> I'll still take the one of 1900, most importantly because it defines the
> SI second.


The SI second was defined as 1/86,400 of a mean solar day, for some year in
the early 19th century. I don't remember exactly what year that was. 1820?
1840? 1850?

Evidently it isn't practical to update the length of the SI second, but
that doesn't mean that calendars have to be based on the ephemeris day, or
atomic day, consisting of 86,400 SI seconds, when that's known to be
different from today's mean solar day.

That's why I suggest 365.24217 instead of 365.24219 for the length of the
mean tropical year (MTYI. It makes sense to base a calendar leap-year
rule's mean-year on the actual length of a tropical-year (whichever one we
want to use) on the length of that tropical year in* today's* mean days.


>
>
> So, contemplating changing the year is non trivial.


Evidently there must be some reason why it would be impractical to update
the length of the SI second. But it isn't necessary to call a MTY 365.24219
days, when it's really 365.24217 mean days