Re: [Paparazzi-devel] Paparazzi-devel Digest, Vol 96, Issue 64

[Martin Mueller]

Hi Henri,

> UTC is 12:57:38.020  and GPS:itow is 305873250.

ITOW is milliseconds since Sunday 0:00

305873.250 / 86400 = 3.54 (3 = Wednesday)

0.54 * 24 = 12.96 (12:xx:yy)

0.96 * 60 = 57.88 (12:57:yy)

0.88 * 60 = 53 (12:57:53)

15 leap seconds from 1980 until today
http://en.wikipedia.org/wiki/Leap_second

53 - 15 = 38 (12:57:38.250)

the other way around (not using leap seconds)
https://github.com/paparazzi/paparazzi/blob/master/sw/airborne/subsystems/gps/gps_mtk.c#L92

Martin

On 26.03.2012 18:38, Henri Pierre wrote:
> Ok, thanks for your answer.
> So, where does this information UTC comes from ?
>
>
>
>
>     Message: 2
>     Date: Mon, 26 Mar 2012 17:45:32 +0200
>     From: "Marc Schwarzbach" <address@hidden
>     <mailto:address@hidden>>
>     To: address@hidden <mailto:address@hidden>
>     Subject: Re: [Paparazzi-devel] UTC and gps:itow in log files
>     Message-ID: <address@hidden
>     <mailto:address@hidden>>
>     Content-Type: text/plain; charset="utf-8"
>
>     Dear Henri,
>
>     thats an issue with the leap seconds reflected in UTC
>     http://en.wikipedia.org/wiki/Coordinated_Universal_Time
>
>     GPS overall time has started in the 80s and does not count for them.
>
>     Should be a searchable issue...
>
>     Cheers
>
>     Marc
>
>
>     -------- Original-Nachricht --------
>      > Datum: Mon, 26 Mar 2012 17:36:19 +0200
>      > Von: Henri Pierre <address@hidden
>     <mailto:address@hidden>>
>      > An: address@hidden <mailto:address@hidden>
>      > Betreff: [Paparazzi-devel] UTC and gps:itow in log files
>
>      > Hello
>      >
>      >
>      > I've just done an export of a flight session using the log
>     plotter and I'm
>      > facing an issue while trying to match
>      > UTC and gps:itow fields. For example on a row :
>      > UTC is 12:57:38.020  and GPS:itow is 305873250.
>      >
>      > According to my calculation, this itow refers to 12:27:53.25
>       which is
>      > different from UTC in the file.
>      >
>      > Do anybody has an explanation ? what does UTC stands for ?
>      >
>      > Regards
>      > Henri
>
>     --
>     NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone!
>     Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a
>
>
>
>     ------------------------------
>
>     _______________________________________________
>     Paparazzi-devel mailing list
>     address@hidden <mailto:address@hidden>
>     https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>
>
>     End of Paparazzi-devel Digest, Vol 96, Issue 64
>     ***********************************************
>
>
>
>
> _______________________________________________
> Paparazzi-devel mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel