Re: [time-nuts] Navsync CW25 undocumented messages
Hi Mark, The CW25 is the model number of the little circuit board, but the model number for the GPS module itself is CW12. So if you search google for , you'll find the user's manual for the CW12. At least, it's the version that emulates the Motorola M12. Ed ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] True position unlocking
I have a few Tru-Position boards. This is an older older GPSDO board for telecom industries. I am using this with LadyHeather. All hooked up, it locks and works; but, quite often Lady Heather shows the red line in graph, showing it is unlocked. I have several GPSDO board here, and for all others, antenna and signal strength are just fine. Ambient temperatures are "human comfortable". I am concerned with this frequent unlock. It happens few times a day and it will eventually RE-locks. Does anybody know what is happening? --- (Mr.) Taka Kamiya I'm stuck in a wormhole Hello, worms! ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Trimble 2101 Plus
Dear all I have just rescued a Trimble 2101 Plus aircraft GPS Can I rescue a descent frequency standard from it Regards Paul B ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS week rollover grounds airplanes
Apparently the rollover grounded some airplanes... oops... https://arstechnica.com/information-technology/2019/04/gps-rollover-apparently-cause-of-multiple-flight-delays-groundings/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Garmin GPS12XL V3.51
> There's another relatively simple clue in the old GPS signal: the leap > second count! A device manufacturer could teach it what the leap second > count was at manufacturing time, and how to predict a lower bound on the > leap second count in the future (with a suitable safety margin / fudge > factor) which should allow it to live a bit more than 20 years. The idea was proposed 20+ years ago, Trimble even has a patent on it. Details here: http://leapsecond.com/notes/gpswnro.htm But it turns out not to work. Earth rotation is too difficult to predict 20, 40, or 60 years into the future. There was talk that the GPS receiver failures in 2015 were related to this algorithm. Look for any threads with subjects like: TS2100, TymServe 2100, 1995 rollover, Trimble ACE, Heol Design in: http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-May/ http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-June/ /tvb - Original Message - From: "Tony Finch" To: "Discussion of precise time and frequency measurement" Sent: Tuesday, April 09, 2019 4:08 AM Subject: Re: [time-nuts] Garmin GPS12XL V3.51 > Leo Bodnar wrote: > >> Assume that the device does not have any reliable long term non-volatile >> memory that you can update. > >> In the absence of any clues your only reliable piece of knowledge is >> that the cold start date is somewhere after the date of manufacturing >> or, most often, firmware compilation date. > > There's another relatively simple clue in the old GPS signal: the leap > second count! A device manufacturer could teach it what the leap second > count was at manufacturing time, and how to predict a lower bound on the > leap second count in the future (with a suitable safety margin / fudge > factor) which should allow it to live a bit more than 20 years. > > Tony. > -- > f.anthony.n.finchhttp://dotat.at/ > Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7 in > south. Moderate. Showers at first in south. Good, occasionally moderate at > first. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Garmin GPS12XL V3.51
Leo Bodnar wrote: > Assume that the device does not have any reliable long term non-volatile > memory that you can update. > In the absence of any clues your only reliable piece of knowledge is > that the cold start date is somewhere after the date of manufacturing > or, most often, firmware compilation date. There's another relatively simple clue in the old GPS signal: the leap second count! A device manufacturer could teach it what the leap second count was at manufacturing time, and how to predict a lower bound on the leap second count in the future (with a suitable safety margin / fudge factor) which should allow it to live a bit more than 20 years. Tony. -- f.anthony.n.finchhttp://dotat.at/ Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7 in south. Moderate. Showers at first in south. Good, occasionally moderate at first. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
