[Ovmsdev] Time variable
Stephen Casner
casner at acm.org
Thu Nov 7 14:20:54 HKT 2019
Yes, just add 1024 * 7 * 86400 to the return value unconditionally.
-- Steve
On Thu, 7 Nov 2019, Mark Webb-Johnson wrote:
>
> The issue is that we don’t have week numbers from the GPS (and presumably week to date is non-trivial).
>
> We get the date/time from the NMEA RMC message, then pass it into this to convert to a julian date/time:
>
> /**
> * utc_to_timestamp:
> * convert GPS date & time (UTC) to timestamp
> * date: "ddmmyy"
> * time: "hhmmss"
> */
> static unsigned long utc_to_timestamp(const char* date, const char* time)
> {
> int day, month, year, hour, minute, second;
>
> day = (date[0]-'0')*10 + (date[1]-'0');
> month = (date[2]-'0')*10 + (date[3]-'0');
> year = (date[4]-'0')*10 + (date[5]-'0');
>
> hour = (time[0]-'0')*10 + (time[1]-'0');
> minute = (time[2]-'0')*10 + (time[3]-'0');
> second = (time[4]-'0')*10 + (time[5]-'0');
>
> return
> (JdFromYMD(2000+year, month, day) - JDEpoch) * (24L * 3600)
> + ((hour * 60L + minute) * 60) + second;
> }
>
> Perhaps sufficient to add 1024 * 7 * 86400 to that?
>
> Regards, Mark.
>
> > On 7 Nov 2019, at 1:44 PM, Stephen Casner <casner at acm.org> wrote:
> >
> > Mark,
> >
> > You don't need the condition "date <2019-11-03", just always add 1024
> > weeks to the current time value coming from the modem.
> >
> > -- Steve
> >
> > On Thu, 7 Nov 2019, Mark Webb-Johnson wrote:
> >
> >> Damn:
> >>
> >> https://www.cika.com/soporte/Information/GSMmodules/GPS-week-rollover_Simcom.pdf <https://www.cika.com/soporte/Information/GSMmodules/GPS-week-rollover_Simcom.pdf>
> >>
> >> I think we can do a fix in the SIMCOM module that if the date <2019-11-03 then offset it somehow? Any ideas?
> >>
> >> Regards, Mark.
> >>
> >>> On 7 Nov 2019, at 1:09 PM, Stephen Casner <casner at acm.org> wrote:
> >>>
> >>> This page mentions the problem:
> >>>
> >>> https://techship.com/news/gps-week-roll-over-issue-during-epoch-restart/
> >>>
> >>> Quoting there:
> >>>
> >>> For the Qualcomm MDM9x15 series (4G/LTE Cat 3) and MDM6200
> >>> (3G/HSPA+) series chipsets there is a offset used, so the GPS week
> >>> roll over will occur 1054+1023 weeks since launch of the GPS, and
> >>> more precisely in beginning of November 2019 (UTC 23:59:42
> >>> November 2, 2019)
> >>>
> >>> [snip]
> >>>
> >>> 3G/HSPA+ modules based on Qualcomm MDM6200 series chipsets:
> >>> Huawei EM820W / MU609 series
> >>> Telit DE910 series
> >>> Simcom SIM5320 series
> >>>
> >>> This sounds like the hardware/firmware won't be fixed. Perhaps the
> >>> solution for OVMS is just to put an offset as a workaroud. That will
> >>> work for the next 1024 weeks.
> >>>
> >>> -- Steve
> >>>
> >>> On Wed, 6 Nov 2019, Stephen Casner wrote:
> >>>
> >>>> Sorry, I did not read carefully. The item you mentioned is just an
> >>>> antenna. The GPS implementation is in the modem module, correct?
> >>>> That's where the correction is needed.
> >>>>
> >>>> -- Steve
> >>>>
> >>>> On Thu, 7 Nov 2019, Tamás Kovács wrote:
> >>>>
> >>>>> I use a universal gps connected to ovms, not the car own gps. (
> >>>>> https://www.fasttech.com/products/1020200)
> >>>>>
> >>>>> Stephen Casner <casner at acm.org> ezt írta (időpont: 2019. nov. 7., Cs, 0:42):
> >>>>>
> >>>>>> Tamás,
> >>>>>>
> >>>>>> This looks like the GPS sensor did not handle the rollover of the
> >>>>>> 10-bit week-number field in April, 2019. So the timestamps are off by
> >>>>>> 1024 * 7 * 24 * 60 * 60 seconds. Here is the US government alert about
> >>>>>> this problem:
> >>>>>>
> >>>>>>
> >>>>>> https://www.us-cert.gov/sites/default/files/documents/Memorandum_on_GPS_2019.pdf
> >>>>>>
> >>>>>> This problem was recently discovered for the Garmin GPS 18x LVC
> >>>>>> sensors in the Tesla Roadster 2.5 (but not in the earlier 1.5 version
> >>>>>> like I have, which has the older GPS 18 LVC sensor):
> >>>>>>
> >>>>>>
> >>>>>> https://teslamotorsclub.com/tmc/threads/caution-annual-service-car-power-down-gps-issue.163328/
> >>>>>>
> >>>>>> There is a firmware update to fix this for the GPS 18x LVC. Perhaps
> >>>>>> there is one for the GPS sensor in the Mitsubishi as well.
> >>>>>>
> >>>>>> -- Steve
> >>>>>>
> >>>>>> On Wed, 6 Nov 2019, Tamás Kovács wrote:
> >>>>>>
> >>>>>>> I have a problem with utc time, the time is correct but the date is not
> >>>>>>> valid. I use 3.2.005-99-g88cfeef9 version with modification of Mitsubishi
> >>>>>>> i-MiEV.
> >>>>>>>
> >>>>>>> OVMS# me li utc
> >>>>>>> m.time.utc 953756768Sec
> >>>>>>> I (900675) housekeeping: 2000-03-22 21:27:06 CET (RAM: 8b=82812-86452
> >>>>>> 32b=27308)
> >>>>>>> I (981115) webserver: HTTP POST /api/execute
> >>>>>>> I (981115) webcommand: HttpCommandStream[0x3fa32958]: 1984428 bytes
> >>>>>>> free, executing: time
> >>>>>>> OVMS# time
> >>>>>>> Time Zone: CET-1CEST,M3.5.0,M10.5.0/3
> >>>>>>> UTC Time: 2000-03-22 20:28:27 UTC
> >>>>>>> Local Time: 2000-03-22 21:28:27 CET
> >>>>>>> Provider: gsm-nmea
> >>>>>>>
> >>>>>>> PROVIDER STRATUM UPDATE TIME
> >>>>>>> *gsm-nmea 2 0 Wed Mar 22 20:28:27 2000
> >>>>>>>
> >>>>>>>
> >>>>>>> --
> >>>>>>> Üdvözlettel:
> >>>>>>> Kovács Tamás_______________________________________________
> >>>>>> OvmsDev mailing list
> >>>>>> OvmsDev at lists.openvehicles.com
> >>>>>> http://lists.openvehicles.com/mailman/listinfo/ovmsdev
> >>>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> Üdvözlettel:
> >>>>> Kovács Tamás
> >>> _______________________________________________
> >>> OvmsDev mailing list
> >>> OvmsDev at lists.openvehicles.com
> >>> http://lists.openvehicles.com/mailman/listinfo/ovmsdev
> >>
> > _______________________________________________
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