Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
This agrees with what Kasper Pedersen wrote earlier: 3.10 starts transmitting 350ms .. 480ms after PPS 3.30 starts transmitting 920ms .. 1220ms (!) after PPS 3.50 starts transmitting 700ms .. 1220ms (!) after PPS Folks, With some help from Hal Murray who knows more of NTP than I do, we have worked round this problem as described here: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm#gps-18x The basic steps were: - make the GPX18x LVC noselect so that NTP would not use it - enable the peerstats to measure where NTP thought the 18x end of message occurred - analyse the peerstats file to determine the apparent offset (which was -1.000 seconds, as it happened) - add that offset (as +1.000 seconds) to the fudge time2 value for the 18x in the ntp.conf - restart NTP I hope that helps someone. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Kevin, Geoff, Joseph, and anyone else who has this problem Thanks to Geoff for those measurements. I had an e-mail response from Garmin which suggested turning off the position averaging introduced as a new option in 3.50 firmware. Whilst that may have helped a little, I still saw (at 19200 baud) sentences starting during the PPS signal, i.e. more than one second delayed. This using a single GPS sentence. The Garmin rep who wrote to me suggested that Garmin were unaware of the problem, but would investigate it. Could I urge you all to report this problem to Garmin, please, so that we have a greater chance of getting a fix in the next firmware upgrade? Thanks, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
On Jan 5, 2011, at 1:15 AM, David J Taylor wrote: [...] The Garmin rep who wrote to me suggested that Garmin were unaware of the problem, but would investigate it. Could I urge you all to report this problem to Garmin, please, so that we have a greater chance of getting a fix in the next firmware upgrade? David, that's a fine idea. Do you have an email address (or other contact info) where our reports of this issue have a greater chance of getting to the firmware group compared to being forwarded to a write-once, read-never file? Kevin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
David, that's a fine idea. Do you have an email address (or other
contact info)
where our reports of this issue have a greater chance of getting to the
firmware
group compared to being forwarded to a write-once, read-never file?
Kevin
Kevin,
I only have a generic e-mail address:
product [period] support {at-sign} garmin [dot] com
but perhaps by putting the case number in the subject and body of the text
it might get added to the case: KMM19596806I15977L0KM I have written to
the Garmin Europe person that I am happy to talk directly to the
developers and to try beta firmware, but I don't hold out much hope of
direct contact!
Cheers,
David
--
SatSignal software - quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
david-tay...@blueyonder.co.uk said: I had an e-mail response from Garmin which suggested turning off the position averaging introduced as a new option in 3.50 firmware. Whilst that may have helped a little, I still saw (at 19200 baud) sentences starting during the PPS signal, i.e. more than one second delayed. This using a single GPS sentence. I think you will have a much better chance of getting Garmin to fix something if we can come up with a clear description of what is broken and/or a simple recipe for a setup that demonstrates the problem. What do you mean by more than one second delayed? That sounds like you are looking at the wrong PPS signal. Could you describe your test setup? I don't see a problem with a delay as long as it's reasonably stable. ntpd has fudge time1 to correct for that. (Even the old working firmware had a horrible delay.) Jitter would be a problem. What sort of range of delays are you seeing? Kiwi Geoff reported about 150 ms of jitter. That's ugly, but I think we can live with it. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
I think you will have a much better chance of getting Garmin to fix something if we can come up with a clear description of what is broken and/or a simple recipe for a setup that demonstrates the problem. What do you mean by more than one second delayed? That sounds like you are looking at the wrong PPS signal. Could you describe your test setup? I don't see a problem with a delay as long as it's reasonably stable. ntpd has fudge time1 to correct for that. (Even the old working firmware had a horrible delay.) Jitter would be a problem. What sort of range of delays are you seeing? Kiwi Geoff reported about 150 ms of jitter. That's ugly, but I think we can live with it. Hal, If the delay were always less than one second, and reasonably stable, it would indeed be something we could live with, and something which could be compensated for in ntpd, for example. With earlier versions of the firmware, the serial output started some hundreds of milliseconds after the leading edge of the PPS signal, and there was no ambiguity as to which second the serial data referred. However, with later versions of the firmware that delay has now reached almost one second, and sometimes is more than one second, leading to an ambiguity about which to PPS second the serial data refers. Test setup is an oscilloscope connected to the serial and PPS outputs of the GPS, with the two channels displays set to chop mode for simultaneous display (i.e. not alternate display). When triggering from the PPS leading edge, the serial output can be seen drifting across the PPS signal, with the serial output sometimes starting after the leading edge. When triggering from the start of the serial output, the PPS signal starts mostly after the serial output, but sometimes the PPS has already started when the serial output starts. So what started as a few hundred milliseconds delay with earlier firmware has now stretched to a delay of around one second, resulting in an ambiguity as to which leading PPS edge the serial output refers. Is that clear enough? Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Hal Murray wrote: It would be really neat if you could run similar experiments on 3.3 and/or 3.5. I have run some more tests Hal, with V3.5, averaging ON and OFF. I include V3.2 for comparison. I measured the time of the START character ($) of the $GPRMC sentence and the LAST 0x10 (Linefeed) character, relative to the leading transition of the 1PPS, GPS 18x set to 4800 Baud. Version 3.20 firmware for Garmin 18x START Min = 370 START Avg = 433 (N = 7200) START Max = 518 LAST Min = 519 LAST Avg = 582 (N = 7200) LAST Max = 667 Version 3.50 firmware for Garmin 18x with Averaging ON START Min = 768 START Avg = 813 (N = 4194) START Max = 871 LAST Min = 917 LAST Avg = 962 (N = 4194) LAST Max = 1020 ( 7 sentences finished over 1,000 ms) Version 3.50 firmware for Garmin 18x with Averaging OFF START Min = 769 START Avg = 805 (N = 3563) START Max = 858 LAST Min = 918 LAST Avg = 954 (N = 3563) LAST Max = 1007 ( 4 sentences finished over 1,000 ms) This agrees with what Kasper Pedersen wrote earlier: 3.10 starts transmitting 350ms .. 480ms after PPS 3.30 starts transmitting 920ms .. 1220ms (!) after PPS 3.50 starts transmitting 700ms .. 1220ms (!) after PPS The averaging appears to have about an 8 ms penalty in delaying the NMEA data stream. We can see in the above, that V3.5 RMC is infrequently not finishing within the correct second ! For my application I need both RMC and GGA to finish within the current second - which the Garmin 18x does very comfortably with version 3.2 and under. Kevin Rosenberg wrote: Has anyone had trouble with reverting firmware upgrades on Garmin products? Of course, feedback on going back from 3.50 to 3.20 on an 18x would be most specific to my situation. I have reverted quite a number of times now Kevin - trying to understand why the 18x can be 1 second slow. I have never had an issue putting in an older version into the 18x, the updater software does know what your doing, it says: Your current software version is newer than the update version. Do you want to replace your current software version with an older version ? We click the YES box. To do the above timing tests I had v3.5 loaded into my 18x, I then reverted to v3.2 and everything worked fine Kevin (to answer your specific question). Regards, Kiwi Geoff (New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
On Jan 5, 2011, at 4:08 AM, Kiwi Geoff wrote: I have reverted quite a number of times now Kevin - trying to understand why the 18x can be 1 second slow. I have never had an issue putting in an older version into the 18x, the updater software does know what your doing, it says: Hi Geoff (of Kiwiland), Thanks for the information and testing. Having had my 3.50 18x and NTP report that NMEA time is -1.00 seconds compared to PPS time, I'll give 3.20 a whirl. I've certainly bricked my share of devices by attempting to reverse the timeline of firmware images. Manufacturer's have cavalierly deemed such attempts to install an older firmware image as being unsupported. I tend to think of it more of as programmers, for reasons as diverse as lack of time, talent, technology, or imagination, who create insufficiently robust installers. It's very nice of you to actually test going from 3.50 to 3.20 for the rest of us. Kevin (of New Mexicoland) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Joseph Gray wrote: If I am using the NMEA data (as in the Garmin is the only time source), what firmware is recommended by all those using a GPS18x-LVC? I thought I would run some tests for you Joe, using Version 3.0 and 3.2 Although I myself have run version 3.0 for a number of months (when it first came out in 2009) without issues, I take note of what Kasper Pedersen wrote about his experience - so I have now loaded version 3.2 into my 18x, rather than any newer version (until Garmin fix the NMEA latency issue). I ran my tests for 2 hours each (7,200 one second samples) with GPS sitting on an inside window sill with a very limited view of the sky, so my readings should be taken as perhaps worse case rather than from a perfect view of the sky. The GPS was using 9 - 10 satellites for the fix solution during the test. The RF sensitivity of the 18x is much better than the Garmin 18. I measured the time of the START character ($) of the $GPRMC sentence and the LAST 0x10 (Linefeed) character, GPS 18x set to 4800 Baud. Following times are in milliseconds from the leading edge of the 1PPS marker. Version 3.00 firmware for Garmin 18x START Min = 365 START Avg = 427 (N = 7200) START Max = 499 LAST Min = 513 LAST Avg = 576 (N = 7200) LAST Max = 648 Version 3.20 firmware for Garmin 18x START Min = 370 START Avg = 433 (N = 7200) START Max = 518 LAST Min = 519 LAST Avg = 582 (N = 7200) LAST Max= 667 So if you use Version 3.20 firmware for the 18x, at 4800 baud the NMEA RMC sentence will give the time of the current UTC second and will be received by an average of 582 ms after the leading edge of the 1PPS transition (with a maximum jitter of plus 85 ms / minus 63 ms). From what I have said earlier in the thread, and from tests that Kasper Pedersen has done, I think we can say that currently version 3.2 is the best version if you want to use the 18x NMEA timestamps to be given early in the second (rather than much later as per version 3.3 and 3.5). Joe, you can downloadGPS18xPC_LVC_320.exe from here: http://www.gawisp.com/perry/oem_sensor/ The above file is identical to the one I downloaded in 2009 from Garmin. Hope that helps. Regards, Geoff (Christchurch, New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Geoff, Thanks a lot for comparing firmwares. That hard information helps tremendously. Joe Gray W5JG On Tue, Jan 4, 2011 at 8:46 PM, Kiwi Geoff geof...@gmail.com wrote: Joseph Gray wrote: If I am using the NMEA data (as in the Garmin is the only time source), what firmware is recommended by all those using a GPS18x-LVC? I thought I would run some tests for you Joe, using Version 3.0 and 3.2 Although I myself have run version 3.0 for a number of months (when it first came out in 2009) without issues, I take note of what Kasper Pedersen wrote about his experience - so I have now loaded version 3.2 into my 18x, rather than any newer version (until Garmin fix the NMEA latency issue). I ran my tests for 2 hours each (7,200 one second samples) with GPS sitting on an inside window sill with a very limited view of the sky, so my readings should be taken as perhaps worse case rather than from a perfect view of the sky. The GPS was using 9 - 10 satellites for the fix solution during the test. The RF sensitivity of the 18x is much better than the Garmin 18. I measured the time of the START character ($) of the $GPRMC sentence and the LAST 0x10 (Linefeed) character, GPS 18x set to 4800 Baud. Following times are in milliseconds from the leading edge of the 1PPS marker. Version 3.00 firmware for Garmin 18x START Min = 365 START Avg = 427 (N = 7200) START Max = 499 LAST Min = 513 LAST Avg = 576 (N = 7200) LAST Max = 648 Version 3.20 firmware for Garmin 18x START Min = 370 START Avg = 433 (N = 7200) START Max = 518 LAST Min = 519 LAST Avg = 582 (N = 7200) LAST Max= 667 So if you use Version 3.20 firmware for the 18x, at 4800 baud the NMEA RMC sentence will give the time of the current UTC second and will be received by an average of 582 ms after the leading edge of the 1PPS transition (with a maximum jitter of plus 85 ms / minus 63 ms). From what I have said earlier in the thread, and from tests that Kasper Pedersen has done, I think we can say that currently version 3.2 is the best version if you want to use the 18x NMEA timestamps to be given early in the second (rather than much later as per version 3.3 and 3.5). Joe, you can download GPS18xPC_LVC_320.exe from here: http://www.gawisp.com/perry/oem_sensor/ The above file is identical to the one I downloaded in 2009 from Garmin. Hope that helps. Regards, Geoff (Christchurch, New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
I agree, very helpful, thanks Joseph! I recently got two 18x that I upgraded to 3.50. (I'm starting to work on integrating some M12+T modules to supplement/replace the 18x's). Has anyone had trouble with reverting firmware upgrades on Garmin products? Of course, feedback on going back from 3.50 to 3.20 on an 18x would be most specific to my situation. Thanks in advance! Kevin Rosenberg KR5F On Jan 4, 2011, at 9:29 PM, Joseph Gray wrote: Geoff, Thanks a lot for comparing firmwares. That hard information helps tremendously. Joe Gray W5JG On Tue, Jan 4, 2011 at 8:46 PM, Kiwi Geoff geof...@gmail.com wrote: Joseph Gray wrote: If I am using the NMEA data (as in the Garmin is the only time source), what firmware is recommended by all those using a GPS18x-LVC? I thought I would run some tests for you Joe, using Version 3.0 and 3.2 Although I myself have run version 3.0 for a number of months (when it first came out in 2009) without issues, I take note of what Kasper Pedersen wrote about his experience - so I have now loaded version 3.2 into my 18x, rather than any newer version (until Garmin fix the NMEA latency issue). I ran my tests for 2 hours each (7,200 one second samples) with GPS sitting on an inside window sill with a very limited view of the sky, so my readings should be taken as perhaps worse case rather than from a perfect view of the sky. The GPS was using 9 - 10 satellites for the fix solution during the test. The RF sensitivity of the 18x is much better than the Garmin 18. I measured the time of the START character ($) of the $GPRMC sentence and the LAST 0x10 (Linefeed) character, GPS 18x set to 4800 Baud. Following times are in milliseconds from the leading edge of the 1PPS marker. Version 3.00 firmware for Garmin 18x START Min = 365 START Avg = 427 (N = 7200) START Max = 499 LAST Min = 513 LAST Avg = 576 (N = 7200) LAST Max = 648 Version 3.20 firmware for Garmin 18x START Min = 370 START Avg = 433 (N = 7200) START Max = 518 LAST Min = 519 LAST Avg = 582 (N = 7200) LAST Max= 667 So if you use Version 3.20 firmware for the 18x, at 4800 baud the NMEA RMC sentence will give the time of the current UTC second and will be received by an average of 582 ms after the leading edge of the 1PPS transition (with a maximum jitter of plus 85 ms / minus 63 ms). From what I have said earlier in the thread, and from tests that Kasper Pedersen has done, I think we can say that currently version 3.2 is the best version if you want to use the 18x NMEA timestamps to be given early in the second (rather than much later as per version 3.3 and 3.5). Joe, you can downloadGPS18xPC_LVC_320.exe from here: http://www.gawisp.com/perry/oem_sensor/ The above file is identical to the one I downloaded in 2009 from Garmin. Hope that helps. Regards, Geoff (Christchurch, New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
So, what is the final consensus as to which is the best firmware version to use for NTP purposes? Joe Gray W5JG Any, providing you don't use the NMEA data to get the nearest second, but use a secondary reference source. Bit of a problem for a stand-alone system, though. I certainly would /not/ use 3.50. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
If I am using the NMEA data (as in the Garmin is the only time source), what firmware is recommended by all those using a GPS18x-LVC? Joe Gray W5JG On Fri, Dec 31, 2010 at 1:52 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: So, what is the final consensus as to which is the best firmware version to use for NTP purposes? Joe Gray W5JG Any, providing you don't use the NMEA data to get the nearest second, but use a secondary reference source. Bit of a problem for a stand-alone system, though. I certainly would /not/ use 3.50. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
If I am using the NMEA data (as in the Garmin is the only time source), what firmware is recommended by all those using a GPS18x-LVC? Joe Gray W5JG Kiwi Geoff recommended: __ http://www.gawisp.com/perry/oem_sensor/ From there I downloaded: GPS18xPC_LVC_300.exe __ I would go back to this version, were it not for the act that I had a GPS18x LVC which stopped working, and needed to be replaced by Garmin. There was a suggestion at the time that it was a firmware problem. Here's the list of firmware changes: http://www8.garmin.com/support/download_details.jsp?id=4055 I wonder about the 3.10 update Improved robustness of internal error handling. 73, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
On 12/31/2010 10:20 AM, Joseph Gray wrote: If I am using the NMEA data (as in the Garmin is the only time source), what firmware is recommended by all those using a GPS18x-LVC? Here are measurements on the bad versions: http://n1.taur.dk/permanent/gps18x-330-pps.jpg http://n1.taur.dk/permanent/gps18x-350-pps.jpg Note I am running 115200, not 4800 3.00 kills itself. I had 2 die simultaneously. 3.10 starts transmitting 350ms .. 480ms after PPS 3.30 starts transmitting 920ms .. 1220ms (!) after PPS 3.50 starts transmitting 700ms .. 1220ms (!) after PPS /Kasper Pedersen ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
David Taylor wrote: But which would you trust? I have only run extensive tests on Version 3.00 (for the 18x LVC) so I know I can trust that version with respect the NMEA completing within the second and stability of 1PPS. I admit I just assumed subsequent versions were OK (without testing myself) - so I got caught! When / if Garmin fix this issue with the 18x, I will run thorough tests next time before I commit to using a new version of firmware. Regards, Geoff (Christchurch, New Zealand) Thanks, Geoff. I have just look for that version on the Garmin Web site but could not find it, at least by using the URL: http://www8.garmin.com/software/GPS18xPC_LVC_300.exe http://www8.garmin.com/software/GPS18xPC_LVC_30.exe http://www8.garmin.com/software/GPS18xPC_LVC_3.exe instead of: http://www8.garmin.com/software/GPS18xPC_LVC_350.exe I have yet to hear back from Garmin UK. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
David Taylor wrote: Thanks, Geoff. I have just look for that version on the Garmin Web site but could not find it, David, a quick Google Search found this: http://www.gawisp.com/perry/oem_sensor/ From there I downloaded: GPS18xPC_LVC_300.exe and it is an exact file match for the file I downloaded from Garmin (Feb 2009). Regards, Geoff (Christchurch, New Zealand) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
David, a quick Google Search found this: http://www.gawisp.com/perry/oem_sensor/ From there I downloaded: GPS18xPC_LVC_300.exe and it is an exact file match for the file I downloaded from Garmin (Feb 2009). Regards, Geoff (Christchurch, New Zealand) Your Googling is better than mine! What a very helpful Mr. Geoff and Mr. Perry! I've bookmarked the site for the next time - I did already have something similar but the site had moved. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
So, what is the final consensus as to which is the best firmware version to use for NTP purposes? Joe Gray W5JG On Thu, Dec 30, 2010 at 7:11 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: David, a quick Google Search found this: http://www.gawisp.com/perry/oem_sensor/ From there I downloaded: GPS18xPC_LVC_300.exe and it is an exact file match for the file I downloaded from Garmin (Feb 2009). Regards, Geoff (Christchurch, New Zealand) Your Googling is better than mine! What a very helpful Mr. Geoff and Mr. Perry! I've bookmarked the site for the next time - I did already have something similar but the site had moved. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
So, what is the final consensus as to which is the best firmware version to use for NTP purposes? I don't know, but I trust y'all know about: http://support.ntp.org/bin/view/Support/ConfiguringGarminRefclocks H ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Ooops... 3.50 firmware is still available at garmin.. I had clicked the wrong link.. sorry Le 29/12/2010 09:55, Cook Mike a écrit : Le 29/12/2010 08:32, David J Taylor a écrit : Calling any Garmin 18x users, I noticed this morning that my Garmin 18x was giving the time 1 second slow to UTC - it has been running in sync with UTC for about 2 years now. [] So I wondered, any other folk out there with a Garmin 18x - is it 1 second slow to UTC ? Regards, Kiwi Geoff (Christchurch, New Zealand). Geoff, I see the same effect on my GPS 18x LVC with the 3.50 firmware. Have you reported this to Garmin? To me it's unacceptable that the NMEA output is delayed into the next PPS signal, making the unit much less useful. I measure the NMEA output and it's not even a consistent distance delayed from the PPS, varying quite a bit. It is possible that this has been reported as I do not see 3.50 available on garmin.com. 3.10 is the latest. Could not find anything in faq's or alerts though. It would certainly be useful to have a sentence transmission offset from UTC in the NMEA messages (or at least a new message heading/tailing the list with that in). The NTP driver has a fudge factor for time offset to end of NMEA stream which can be used if you can measure it. You could scope it, (I am checking a MG1613S at the moment) but that is not that easy if you are selecting just one of the many messages being output. An easier method might be to just have NTP tell you what it thinks the offset is when measured against other references, then use that as your fudge factor.(use noselect directive for the NMEA server or set its stratum high so it doesn't get selected). [New to this mailing list, so I had to fabricate this message as a reply to at least try and keep it on thread] Cheers, David ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
The reason it caught me out, is that I had changed to version 3.30 (where it also delays NMEA) on the 27th Sep 2010, and it took a couple of months to manifest as a problem. It was the rising of the sap in my trees combined with windy weather - which pushed the NMEA into the next second for my application. I also noticed a gradual deterioration, but that was going into Winter with fewer branches! Luckily I kept all the 18x firmware versions David, so I could simply reload the firmware that completed the NMEA sentences well before the next PPS. But which would you trust? Yes, that is why it got tricky for me David, because sometimes the GPS gave the correct UTC time, and sometimes the UTC time was one second slow - depending on how much the NMEA sentences were delayed from the PPS. Regards, Kiwi Geoff (NZ). With NTP which is my use of the puck, I could fix it so that /only/ the PPS signal is used, and the coarse nearest second is derived elsewhere, and that's how I'm running right now. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Hi Geoff, Did you and I run into the same issue with NMEA from old Jupiter receivers? (many years ago at the now dead forum at gpskit.nl) -- Björn To me it's unacceptable that the NMEA output is delayed into the next PPS signal, making the unit much less useful. I measure the NMEA output and it's not even a consistent distance delayed from the PPS, varying quite a bit. Yes, that is why it got tricky for me David, because sometimes the GPS gave the correct UTC time, and sometimes the UTC time was one second slow - depending on how much the NMEA sentences were delayed from the PPS. Regards, Kiwi Geoff (NZ). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Björn wrote: Did you and I run into the same issue with NMEA from old Jupiter receivers? (many years ago at the now dead forum at gpskit.nl) We may have Björn, I know we have communicated before, but I'm not sure on what topic(s). I have never owned or played with a Jupiter - so I have never made any tests on one myself. I have only run tests (NMEA w.r.t. PPS) on Trimble SV6, Motorola GT+, Garmin 18 and 18x , Ashtech (Thales) AC12. Geoff wrote: Luckily I kept all the 18x firmware versions David, so I could simply reload the firmware that completed the NMEA sentences well before the next PPS. David Taylor wrote: But which would you trust? I have only run extensive tests on Version 3.00 (for the 18x LVC) so I know I can trust that version with respect the NMEA completing within the second and stability of 1PPS. I admit I just assumed subsequent versions were OK (without testing myself) - so I got caught! When / if Garmin fix this issue with the 18x, I will run thorough tests next time before I commit to using a new version of firmware. Regards, Geoff (Christchurch, New Zealand) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Calling any Garmin 18x users, I noticed this morning that my Garmin 18x was giving the time 1 second slow to UTC - it has been running in sync with UTC for about 2 years now. [] So I wondered, any other folk out there with a Garmin 18x - is it 1 second slow to UTC ? Regards, Kiwi Geoff (Christchurch, New Zealand). Geoff, I see the same effect on my GPS 18x LVC with the 3.50 firmware. Have you reported this to Garmin? To me it's unacceptable that the NMEA output is delayed into the next PPS signal, making the unit much less useful. I measure the NMEA output and it's not even a consistent distance delayed from the PPS, varying quite a bit. [New to this mailing list, so I had to fabricate this message as a reply to at least try and keep it on thread] Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Hal Murray wrote: I assume it was working correctly previously. If not... At least one GPS receiver I've used is off by a second. There is an ambiguity as to whether the time applies to the previous or next PPS. You were correct Hal, the problem with the new firmware for the 18x, is the time relationship between the 1PPS transition and the serial data. My application required the RMC and GGA sentence at 4800 BAUD. So I measured the start and end times of the serial data (with respect the 1PPS). Using version 3.00 firmware on the Garmin 18x, the NMEA data starts 450 ms after the 1PPS transition, and finishes at 740 ms. However using the latest firmware version (3.50) for the 18x, the NMEA data starts at 750 ms and finishes 39 ms into the following second. That is why my software was loading the wrong time. These start and end times of the NMEA serial data change quite a bit as the workload of the GPS changes. There is no mention in all the update notes, that Garmin have changed the timing of the NMEA data with respect the 1PPS transition. Running the same test with my GPS 18, the NMEA starts about 50 ms and finishes 350 ms after the 1PPS transition - nice and reliable! I think the reason my 18x started (in the last few days) to show the wrong time, is that the trees around my house are at the peak of growing leaves (Summer in the Southern Hemisphere) and so this would have caused the GPS to work harder, and so must have delayed the NMEA data enough (with version 3.50) to give the wrong time on the serial data. So the moral of the story, don't expect that a device will be better if you upgrade to the latest version of software. Thanks Hal for your kind pointer - I now understand what is going on, and not to be so excited about new firmware updates. Kiwi Geoff (Christchurch, New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
In my various tinkering it always seems that I have to recreate a software clock that accounts for the behavior thats advanced by 1 second. Have done that on 2-3 projects the most recent being the GOES DC468 simulator. Regards On Thu, Dec 23, 2010 at 5:49 AM, Kiwi Geoff geof...@gmail.com wrote: Hal Murray wrote: I assume it was working correctly previously. If not... At least one GPS receiver I've used is off by a second. There is an ambiguity as to whether the time applies to the previous or next PPS. You were correct Hal, the problem with the new firmware for the 18x, is the time relationship between the 1PPS transition and the serial data. My application required the RMC and GGA sentence at 4800 BAUD. So I measured the start and end times of the serial data (with respect the 1PPS). Using version 3.00 firmware on the Garmin 18x, the NMEA data starts 450 ms after the 1PPS transition, and finishes at 740 ms. However using the latest firmware version (3.50) for the 18x, the NMEA data starts at 750 ms and finishes 39 ms into the following second. That is why my software was loading the wrong time. These start and end times of the NMEA serial data change quite a bit as the workload of the GPS changes. There is no mention in all the update notes, that Garmin have changed the timing of the NMEA data with respect the 1PPS transition. Running the same test with my GPS 18, the NMEA starts about 50 ms and finishes 350 ms after the 1PPS transition - nice and reliable! I think the reason my 18x started (in the last few days) to show the wrong time, is that the trees around my house are at the peak of growing leaves (Summer in the Southern Hemisphere) and so this would have caused the GPS to work harder, and so must have delayed the NMEA data enough (with version 3.50) to give the wrong time on the serial data. So the moral of the story, don't expect that a device will be better if you upgrade to the latest version of software. Thanks Hal for your kind pointer - I now understand what is going on, and not to be so excited about new firmware updates. Kiwi Geoff (Christchurch, New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
I have a similar issue with TAC32 receiving NEMA data from a Rockwell Jupiter based GPS. If any software developers are reading this adding some form of UTC off set functionality to account for this behaviour would be nice (: - Original Message From: paul swed paulsw...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, December 23, 2010 11:43:45 AM Subject: Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC In my various tinkering it always seems that I have to recreate a software clock that accounts for the behavior thats advanced by 1 second. Have done that on 2-3 projects the most recent being the GOES DC468 simulator. Regards ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Is tac32 free to amateurs? On Thu, Dec 23, 2010 at 3:05 PM, Mark Spencer mspencer12...@yahoo.cawrote: I have a similar issue with TAC32 receiving NEMA data from a Rockwell Jupiter based GPS. If any software developers are reading this adding some form of UTC off set functionality to account for this behaviour would be nice (: - Original Message From: paul swed paulsw...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, December 23, 2010 11:43:45 AM Subject: Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC In my various tinkering it always seems that I have to recreate a software clock that accounts for the behavior thats advanced by 1 second. Have done that on 2-3 projects the most recent being the GOES DC468 simulator. Regards ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
I don't believe so. I paid for my copy. - Original Message From: paul swed paulsw...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, December 23, 2010 12:07:07 PM Subject: Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC Is tac32 free to amateurs? On Thu, Dec 23, 2010 at 3:05 PM, Mark Spencer mspencer12...@yahoo.cawrote: I have a similar issue with TAC32 receiving NEMA data from a Rockwell Jupiter based GPS. If any software developers are reading this adding some form of UTC off set functionality to account for this behaviour would be nice (: - Original Message From: paul swed paulsw...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, December 23, 2010 11:43:45 AM Subject: Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC In my various tinkering it always seems that I have to recreate a software clock that accounts for the behavior thats advanced by 1 second. Have done that on 2-3 projects the most recent being the GOES DC468 simulator. Regards ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Calling any Garmin 18x users, I noticed this morning that my Garmin 18x was giving the time 1 second slow to UTC - it has been running in sync with UTC for about 2 years now. Garmin has recently ( 13th Dec 2010 ) changed the 18x firmware from 3.30 to 3.50, so I updated my GPS sensor just now to the new version 3.50 - and it is still 1 second slow to UTC. I tried two of my older Garmin 18 (no x) modules, and they are in sync with UTC. All three Garmins are showing (on the $PGRMF sentence) that the delta between GPS time and UTC is 15 seconds (which is correct). I guess it is that time of the year when pending leap seconds can apply (although Dec 31 2010 is NOT going to be a leap second year). So I wondered, any other folk out there with a Garmin 18x - is it 1 second slow to UTC ? Regards, Kiwi Geoff (Christchurch, New Zealand). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
I noticed this morning that my Garmin 18x was giving the time 1 second slow to UTC - it has been running in sync with UTC for about 2 years now. I assume it was working correctly previously. If not... At least one GPS receiver I've used is off by a second. There is an ambiguity as to whether the time applies to the previous or next PPS. I assume that's why they got it wrong, but maybe they are just off by one for some other reason. So I wondered, any other folk out there with a Garmin 18x - is it 1 second slow to UTC ? I've seen Garmin 18s (probably no x) be off by a second, but that was only for a transient. I haven't chased it. I assumed it was when recovering from not-enough satellites. (I'm running them inside, poor signal.) -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
