Re: [ntp:questions] Problems with Sure OEM pps gps
> Le 18 nov. 2017 à 22:55, William Unruh a écrit : > > I am having sudden problems on my system with a Sure GPS with PPS. > I am running chrony, using a serial port to bring in the PPS signal. > Everything was working well-- the rms timing on the pulse was about 1usec. > Suddenly on Nov 18 at very close to 00:00:00UTC the timing went to hell, and > the > rpms is now at 20us-- the individual pulses have an offset that fluctuates > between about 50us, and -50us. I can just report that I didn’t see any issues with my Sure board at that time. I am getting 1-5us offset reported by NTP pretty much stable all day. > Is there any hint as to what I could do to track down the problem. Could it be > the sattelites (ie the timing has suddenly gone from ns to tens of usec for > some reason? But if this were true I would have expected to hear many many > loud screams here.) Or the gps receiver? (again, unlikely I would think). Or > the serial card? or chrony? Or the computer clock? (the computer was not > rebooted anywhere around that date). Have you checked the antenna. I had one of mine fall off the window ledge which didn’t help. Have you power cycled the receiver? That may kill it, but at least you will know. If you have another computer, connect it to that to see if the problem follows. You could configure it as « noselect » (if possible in chrony) and see if the clock drift is erratic. Borrow an oscilloscope and check the raw PPS signal. If you have a second PPS source, check your config with that in place of the Sure board. > : > By the way, what in the world has happened to this newsgroup? I am getting > about 1 valid message to over 100 Case Solutions? Its very low traffic . Maybe we are considered dummies. > > ___ > questions mailing list > questions@lists.ntp.org > http://lists.ntp.org/listinfo/questions "The power of accurate observation is commonly called cynicism by those who have not got it. » George Bernard Shaw ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Problems with Sure OEM pps gps
On 18/11/2017 21:55, William Unruh wrote: I am having sudden problems on my system with a Sure GPS with PPS. I am running chrony, using a serial port to bring in the PPS signal. Everything was working well-- the rms timing on the pulse was about 1usec. Suddenly on Nov 18 at very close to 00:00:00UTC the timing went to hell, and the rpms is now at 20us-- the individual pulses have an offset that fluctuates between about 50us, and -50us. Is there any hint as to what I could do to track down the problem. Could it be the sattelites (ie the timing has suddenly gone from ns to tens of usec for some reason? But if this were true I would have expected to hear many many loud screams here.) Or the gps receiver? (again, unlikely I would think). Or the serial card? or chrony? Or the computer clock? (the computer was not rebooted anywhere around that date). : By the way, what in the world has happened to this newsgroup? I am getting about 1 valid message to over 100 Case Solutions? Bill, You need to add a filter to your news feed to remove the unwanted postings. Can you check other devices in the same location? I've seen something similar happen when a GPS jamming device was (I guess) parked nearby. You might also check that the serial feed is still OK. -- Cheers, David Web: http://www.satsignal.eu ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Problems with Sure OEM pps gps
On 2017-11-19, David Taylor wrote: > On 18/11/2017 21:55, William Unruh wrote: >> I am having sudden problems on my system with a Sure GPS with PPS. >> I am running chrony, using a serial port to bring in the PPS signal. >> Everything was working well-- the rms timing on the pulse was about 1usec. >> Suddenly on Nov 18 at very close to 00:00:00UTC the timing went to hell, and >> the >> rpms is now at 20us-- the individual pulses have an offset that fluctuates >> between about 50us, and -50us. >> Is there any hint as to what I could do to track down the problem. Could it >> be >> the sattelites (ie the timing has suddenly gone from ns to tens of usec for >> some reason? But if this were true I would have expected to hear many many >> loud screams here.) Or the gps receiver? (again, unlikely I would think). Or >> the serial card? or chrony? Or the computer clock? (the computer was not >> rebooted anywhere around that date). >> : >> By the way, what in the world has happened to this newsgroup? I am getting >> about 1 valid message to over 100 Case Solutions? > > Bill, > > You need to add a filter to your news feed to remove the unwanted postings. t but it is annoying to keep seeing 8 or more postings only to have all of them killed. It is bizzare, and wonder if there is some way of getting google to kill that account. > > Can you check other devices in the same location? I've seen something > similar happen when a GPS jamming device was (I guess) parked nearby. > You might also check that the serial feed is still OK. I have no other devices in the area. All I use is the PPS on that gps receiver, not the nmea. But yes, I do believe it is OK. It is hard to see what could happen in an empty office at 4PM. I will see if I can find another gps receiver. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Problems with Sure OEM pps gps
On 19/11/2017 06:29, William Unruh wrote: []> t but it is annoying to keep seeing 8 or more postings only to have all of them killed. It is bizzare, and wonder if there is some way of getting google to kill that account. Can you check other devices in the same location? I've seen something similar happen when a GPS jamming device was (I guess) parked nearby. You might also check that the serial feed is still OK. I have no other devices in the area. All I use is the PPS on that gps receiver, not the nmea. But yes, I do believe it is OK. It is hard to see what could happen in an empty office at 4PM. I will see if I can find another gps receiver. I have just two e-mail addresses set to filter and delete. I was thinking of a mobile phone as the "test" GPS receiver. If you have an Android phone it will be able to see the individual signal strengths. -- Cheers, David Web: http://www.satsignal.eu ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Problems with Sure OEM pps gps
On 2017-11-19, David Taylor wrote: > On 19/11/2017 06:29, William Unruh wrote: > []> t but it is annoying to keep seeing 8 or more postings >> only to have all of them killed. It is bizzare, and wonder if there is some >> way of getting google to kill that account. >> >>> >>> Can you check other devices in the same location? I've seen something >>> similar happen when a GPS jamming device was (I guess) parked nearby. >>> You might also check that the serial feed is still OK. >> >> I have no other devices in the area. All I use is the PPS on that gps >> receiver, not the nmea. But yes, I do believe it is OK. It is hard to see >> what >> could happen in an empty office at 4PM. >> >> I will see if I can find another gps receiver. > > I have just two e-mail addresses set to filter and delete. > > I was thinking of a mobile phone as the "test" GPS receiver. If you > have an Android phone it will be able to see the individual signal > strengths. > If it cannot see the sattelites, then I would not expect the pps to suddenly pick up a 20usec scatter in the pulse timing. The average seems to track the the time reasonably well (as indicated by the tracking of two external ntp sources-- I am not getting a drift away from their time of the system). Unfortunately, the other Ssure GPS board I have is a different one, based on the Skylark chipset, and the PPS does not seem to be working on it (the pps light does not blink at all) Perhaps it is not switched on, but the Skylark GPS manual does not indicate any way of switching on the PPS, or of sending any NMEA signal to the device-- just proprietary ones which only change the baud rate or do various temperatures of reboot. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
