[time-nuts] GPS receivers and the Leap Second
Hi! In my network I have 2 Meinberg M200 clocks and 4 other GPS receivers (1 Sure GPS Evaluation board, 2 Garmin 18 LVC and a uBlox EVK-6N). I recorded the GPS timecode strings across 00:00 UTC to see how they would react to the leap second: Sure GPS timecode="$GPGGA,235955.000,4055.2138,N,00829.6016,W,2,7,1.11,267.3,M,51.2,M,,*4E", timecode="$GPGGA,235956.000,4055.2138,N,00829.6016,W,2,7,1.11,267.3,M,51.2,M,,*4D", timecode="$GPGGA,235957.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*4F", timecode="$GPGGA,235958.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*40", timecode="$GPGGA,235959.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*41", timecode="$GPGGA,235959.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*41", timecode="$GPGGA,00.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*40", timecode="$GPGGA,01.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*41", timecode="$GPGGA,02.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,,*42", timecode="$GPGGA,03.000,4055.2138,N,00829.6015,W,2,6,1.15,267.3,M,51.2,M,,*46", timecode="$GPGGA,04.000,4055.2138,N,00829.6015,W,2,6,1.15,267.3,M,51.2,M,,*41", timecode="$GPGGA,05.000,4055.2138,N,00829.6015,W,2,7,1.07,267.3,M,51.2,M,,*42", Meinberg #1 timecode="\x0231.12.16; 6; 23:59:55; +00:00; A ; 40.9204N 8.4936W 343m\x03", timecode="\x0231.12.16; 6; 23:59:56; +00:00; A ; 40.9204N 8.4936W 343m\x03", timecode="\x0231.12.16; 6; 23:59:57; +00:00; A ; 40.9204N 8.4936W 343m\x03", timecode="\x0231.12.16; 6; 23:59:58; +00:00; A ; 40.9204N 8.4936W 343m\x03", timecode="\x0231.12.16; 6; 23:59:59; +00:00; A ; 40.9204N 8.4936W 343m\x03", timecode="\x0231.12.16; 6; 23:59:60; +00:00; L; 40.9204N 8.4936W 343m\x03", timecode="\x0201.01.17; 7; 00:00:00; +00:00;; 40.9204N 8.4936W 343m\x03", timecode="\x0201.01.17; 7; 00:00:01; +00:00;; 40.9204N 8.4936W 343m\x03", timecode="\x0201.01.17; 7; 00:00:02; +00:00;; 40.9204N 8.4936W 343m\x03", timecode="\x0201.01.17; 7; 00:00:03; +00:00;; 40.9204N 8.4936W 343m\x03", timecode="\x0201.01.17; 7; 00:00:04; +00:00;; 40.9204N 8.4936W 343m\x03", timecode="\x0201.01.17; 7; 00:00:05; +00:00;; 40.9204N 8.4936W 343m\x03", Meinberg #2 timecode="\x0231.12.16; 6; 23:59:55; +00:00; A ; 40.9205N 8.4936W 337m\x03", timecode="\x0231.12.16; 6; 23:59:56; +00:00; A ; 40.9205N 8.4936W 337m\x03", timecode="\x0231.12.16; 6; 23:59:57; +00:00; A ; 40.9205N 8.4936W 337m\x03", timecode="\x0231.12.16; 6; 23:59:58; +00:00; A ; 40.9205N 8.4936W 337m\x03", timecode="\x0231.12.16; 6; 23:59:59; +00:00; A ; 40.9205N 8.4936W 337m\x03", timecode="\x0231.12.16; 6; 23:59:60; +00:00; L; 40.9205N 8.4936W 337m\x03", timecode="\x0201.01.17; 7; 00:00:00; +00:00;; 40.9205N 8.4936W 337m\x03", timecode="\x0201.01.17; 7; 00:00:01; +00:00;; 40.9205N 8.4936W 337m\x03", timecode="\x0201.01.17; 7; 00:00:02; +00:00;; 40.9205N 8.4936W 337m\x03", timecode="\x0201.01.17; 7; 00:00:03; +00:00;; 40.9205N 8.4936W 337m\x03", timecode="\x0201.01.17; 7; 00:00:04; +00:00;; 40.9205N 8.4936W 337m\x03", timecode="\x0201.01.17; 7; 00:00:05; +00:00;; 40.9205N 8.4936W 337m\x03", uBlox EVK-6N timecode="$GPGGA,235955.00,4055.21472,N,00829.59411,W,1,07,1.11,251.5,M,49.9,M,,*4F", timecode="$GPGGA,235956.00,4055.21472,N,00829.59416,W,1,07,1.11,251.7,M,49.9,M,,*49", timecode="$GPGGA,235957.00,4055.21472,N,00829.59420,W,1,07,1.11,251.8,M,49.9,M,,*42", timecode="$GPGGA,235958.00,4055.21474,N,00829.59424,W,1,08,1.11,252.1,M,49.9,M,,*4A", timecode="$GPGGA,235959.00,4055.21475,N,00829.59429,W,1,08,1.11,252.3,M,49.9,M,,*45", timecode="$GPGGA,235960.00,4055.21477,N,00829.59433,W,1,08,1.11,252.6,M,49.9,M,,*43", timecode="$GPGGA,235960.00,4055.21477,N,00829.59433,W,1,08,1.11,252.6,M,49.9,M,,*43", timecode="$GPGGA,01.00,4055.21479,N,00829.59440,W,1,08,1.11,253.0,M,49.9,M,,*44", timecode="$GPGGA,02.00,4055.21481,N,00829.59443,W,1,08,1.11,253.3,M,49.9,M,,*40", timecode="$GPGGA,03.00,4055.21482,N,00829.59447,W,1,08,1.11,253.6,M,49.9,M,,*43", timecode="$GPGGA,04.00,4055.21484,N,00829.59451,W,1,08,1.11,253.8,M,49.9,M,,*4B", timecode="$GPGGA,05.00,4055.21485,N,00829.59454,W,1,08,1.11,254.1,M,49.9,M,,*40", Garmin 18 LVC #1 timecode="$GPGGA,235955,4055.2362,N,00829.5576,W,2,07,1.2,248.8,M,51.7,M,,*5C", timecode="$GPGGA,235956,4055.2362,N,00829.5576,W,2,07,1.2,248.8,M,51.7,M,,*5F", timecode="$GPGGA,235957,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*53", timecode="$GPGGA,235958,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*5C", timecode="$GPGGA,235959,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*5D", timecode="$GPGGA,235959,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*5D",
Re: [time-nuts] Legal Time dissemination
Hi David! On 5 June 2013 06:58, David J Taylor david-tay...@blueyonder.co.uk wrote: Miguel, I notice a step in the blue (ntp02) graph in: http://www.flickr.com/photos/**miguelbarbosagoncalves/**8955346508/http://www.flickr.com/photos/miguelbarbosagoncalves/8955346508/ and I think in the red (ntp04) graph as well. This suggests some change in connectivity between your monitoring PC and both servers, so perhaps a network change. Unless your stratum-1 server took a 2 millisecond step, which seems unlikely. I believe something has happened but not on my side. The offset for ntp02 changed its sign but kept the absolute value. Their ntp02looks well behaved, but their ntp04 is clearly not well behaved, and disappointing for public service. In my own plotting program: Indeed! Very disappointing! And it is payed by my taxes!!! :-( http://www.satsignal.eu/**software/net.htm#NTPplotterhttp://www.satsignal.eu/software/net.htm#NTPplotter I find it useful to be able to plot the offset versus time of day, as regular temperature variations tend to stand out - at least in my environment where the heating switches on at the same time every morning. For comparison on a similar time scale, you might like to look at my Windows LAN-synced PCs here: http://www.satsignal.eu/mrtg/**performance_ntp.php?period=**week#windowshttp://www.satsignal.eu/mrtg/performance_ntp.php?period=week#windows so even if their servers were running Windows, they could be doing far better than that your graph suggests. Could you plot offset versus time of day? Will do that later today. I am also gathering the offset of my stratum 1 in the same location against ntp02 and ntp04 and another set of stratum 2 servers located in an University. The first 24 hours look rather interesting: ntp02 and these new servers are quite stable (around 1 ms offset in absolute value) and ntp04 keeps doing crazy things. Once I have enough data I will contact them. Cheers, Miguel ___ 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] Legal Time dissemination
Two mistakes that I spotted after clicking send... On 5 June 2013 01:57, Miguel Barbosa Gonçalves m...@mbg.pt wrote: Hi Chis! I meant Chris of course... sorry about that! I have a week's worth of data know... Take a look at the attached graphics. Not know but now of course... 2 am here :-) Cheers, Miguel ___ 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] Legal Time dissemination
Hi Chris! I have a week's worth of data now... Take a look at these graphics http://www.flickr.com/photos/miguelbarbosagoncalves/8955346508/ and http://www.flickr.com/photos/miguelbarbosagoncalves/8955346522/ One of them shows is the plot of the loopstats of my stratum 1 server. The other one shows the offset determined every minute of their servers compared to mine. On 28 May 2013 16:11, Chris Albertson albertson.ch...@gmail.com wrote: The stratum 2 servers are by definition not connected to GPS. They get their time from some other NTP server that is connected to an authoritative clock which may or may not be GPS.It looks like the red server has I know that but I would expect good stratum 2 servers if they are keeping their stratum 1 servers private and not available to the public. rather smooth swings over around a handful of milliseconds. This is to be excepted. It is within the normal range of what NTP does. Perhaps it is a Windows PC running in some room where the temperature changes and the network that connects it to the strum 1 server is loaded. I don't know but a handful of milliseconds is in the normal range. Yes it could be better. I don't believe it is a Windows server but I could be wrong... Also the curve is somewhat smooth. It does not look like noise from a busy network. It looks like their server really is moving around. I believe they are on the same network. It looks like a temperature problem really. Thanks for all the input! Kind regards, Miguel ___ 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] NTP Clock suggestions?
On 27 May 2013 18:11, David J Taylor david-tay...@blueyonder.co.uk wrote: From: Miguel Barbosa Gonçalves [] Just checked the Windows taskbar clock and it has a 1 second delay... At work I use Windows but use Mac OS X at home... but I am looking for a solution for the Windows platform. TIA, Miguel ==**= Both analogue and digital display, screen or taskbar (or both), UTC options, and should not have a 1-second delay: http://www.satsignal.eu/**software/disk.html#TinyBenhttp://www.satsignal.eu/software/disk.html#TinyBen Hi David! Many thanks! It really does not have the 1 second delay. Great piece of software! Cheers, Miguel ___ 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] Legal Time dissemination
Hi! Lately I've been using the two stratum 2 servers our national observatory provides to the public mainly as backup for my GPS based local NTP servers. I've always found odd that one of them exhibited an erratic behaviour when compared to the other one. I decided to use ntpdate on one of my stratum 1 machines (Trimble AcutimeGold in position hold mode; looking at my loopstats file my clock is always within 5 us of UTC) against these 2 servers every minute for a while and plotted the results. Offset is in seconds and time is UTC. I am on a fibre asymmetrical connection 100 Mbps/25 Mbps. The offsets for the best behaved server are expected but... the other server? After gathering enough data I'll contact them as ask what is the problem with the server... Opinions? Regards, Miguel National Observatory NTP Performance.pdf Description: Adobe PDF document ___ 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] Legal Time dissemination
On 28 May 2013 14:10, Gabs Ricalde gsrica...@gmail.com wrote: That looks like a server in an room with unstable temperature. Try graphing the server's frequency (ntpq rv or ntpdc loopinfo/kerninfo if enabled on the server), a rising frequency will correlate with a positive offset if that is the case. Hi! They've disabled the queries on both servers because I believe that don't want to see how badly they are configured... :-) Regards, Miguel ___ 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] Legal Time dissemination
Hi Jason! On 28 May 2013 13:56, Jason Rabel ja...@extremeoverclocking.com wrote: I would do a traceroute and see if the path is the same going to both servers, that can eliminate some variables. They are on the same network and the path is the same. Beyond that it would take some detective work on their side. It could be the hardware for each machine is different. Different poll lengths. Different server loads. Different NTP versions. Different antenna locations and one is getting some interference. You can try doing a: ntpq -c rv (remote ip) to see if you can query the stats of the remote machines, that might give you some clues as to what's going on. They've disabled the queries on their servers. These are stratum 2 servers asking time from other 4 stratum 1 servers which are in turn connected to GPS receivers and cesium clocks. This is what they've told me a while ago... Regards, Miguel ___ 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] NTP Clock suggestions?
Hi! I was wondering if anyone knows about a not so expensive wall digital clock that gets its time from an NTP server... TIA, Miguel ___ 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] NTP Clock suggestions?
Hi Bob! On 27 May 2013 14:56, Bob Camp li...@rtty.us wrote: Hi Correct answer: I don't think there is such a beast. Once you get away from the radio controlled (WWVB etc) clocks the cost goes up quickly. I don't understand why a microprocessor with an Ethernet controller and a 7 segment display would cost so much to manufacture... I think I'll build my own. Also correct, but a bit of a joke answer: Raspberry PI driving your television set. Alternatively make the Pi feed control signals to a hacked normal clock. Good joke :-) I imagine the electricity bill at the end of the month. I would like to have a clock sync with my super precise stratum 1 servers :-) what's the point in having them if I can see the time anywhere? :-) Cheers, Miguel ___ 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] NTP Clock suggestions?
On 27 May 2013 16:22, Chris Albertson albertson.ch...@gmail.com wrote: On Mon, May 27, 2013 at 7:56 AM, Miguel Barbosa Gonçalves m...@mbg.pt wrote: Good joke :-) I imagine the electricity bill at the end of the month. I would like to have a clock sync with my super precise stratum 1 servers :-) what's the point in having them if I can see the time anywhere? :-) Don't know about you but I'm always in from of a computer and the time is one the screen in the upper right corner. Just checked the Windows taskbar clock and it has a 1 second delay... At work I use Windows but use Mac OS X at home... but I am looking for a solution for the Windows platform. TIA, Miguel ___ 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] Trimble Acutime Gold PPS
Hi! I am struggling trying to convert my Acutime's PPS signal from RS422 to RS232 for NTP use. I am using this converter: http://www.dpieshop.com/quatech -sscvt500n-rs232-to-rs422485-serial-converter-p-282.html and I connected - Port A (T+) to R+ on the converter - Port A (T-) to R- on the converter - PPS+ to T+ on the converter - PPS- to T- on the converter On the RS232 part of the converter - TXD (pin 3) to computer pin 1 (DCD) - RXD (pin 2)to computer pin 2 (RXD) - GND (pin 5)to computer pin 5 (GND) all other pins are connected to the same pin on the computer except for the DCD on the converter which is not connected. I can see the serial time code on the computer yet the PPS (a long 400 ms one) doesn't seem to reach the computer. I've tried everything I could remember off and connecting the RS422 PPS+ pin directly to the computer makes the NTP daemon stop randomly and losing the PPS signal. I really think I need to convert the PPS signal (30 meters long cable). Without PPS and using this converter NTP works fine. The problem is the jitter I am getting. I think I've exhausted every option with this converter and found this converter: http://www.ko4bb.com/~bruce/GPS_RS232_RS422_Transceiver.html. I might try it. Anyone here tried it or has any input for this situation?? I also think that from a time nut perspective building my converter instead of using a black box will enable me to see what is the delay in the signal conversion. Any help would be highly appreciated. Kind regards, Miguel ___ 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] Trimble Acutime Gold PPS
No dia 19/05/2013, às 22:44, Mike S mi...@flatsurface.com escreveu: On 5/19/2013 5:03 PM, Miguel Barbosa Gonçalves wrote: - Port A (T+) to R+ on the converter - Port A (T-) to R- on the converter - PPS+ to T+ on the converter - PPS- to T- on the converter On the RS232 part of the converter - TXD (pin 3) to computer pin 1 (DCD) - RXD (pin 2)to computer pin 2 (RXD) - GND (pin 5)to computer pin 5 (GND) I can see the serial time code on the computer yet the PPS (a long 400 ms one) doesn't seem to reach the computer. You're trying to have two different signals sourced on the 422 side converted to 232 outputs. That converter is bidirectional, it converts one signal from 422 to 232, and another from 232 to 422. Your PPS signal is going into an output on the converter. Hi!! I suspected that this could be the case. I think I'll build the converter whose schematic I posted previously. I will be entertained for a few days for sure. Thanks for your help! Regards, Miguel ___ 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] Imagery position accuracy
On 07/05/2013, at 01:20, Chris Albertson albertson.ch...@gmail.com wrote: On Mon, May 6, 2013 at 3:38 PM, Miguel Barbosa Gonçalves m...@mbg.pt wrote: .. You'll have to make the driver talk to the configuration / monitoring port (port B) as the timing port (port A) does not accept commands. So this does not apply to the Thunderbolt? It only has one port. If it worked on all PALISADE type GPSes I'd do it. With this configuration I can stop using the PALISADE driver and configure the Acutime to send NMEA sentences and use the PPS for better accuracy. NEMA is only used to number the seconds. It is the PPS that does the timing. You don't gain accuracy with NEMA. Chris, I know NMEA is *usually* only used to number seconds. Usually, the manufacturers don't care with the accuracy of the NMEA sentences but in theory if they were output precisely they could be used with NTP. For I time nut I believe that would not be enough. But did you actually read what I wrote? ;) I said that with my configuration I can use the PALISADE or NMEA and PPS. Actually I am using PPS on both as the PALISADE only gives me too much jitter on my serial port. After several hours running some interesting data: acutime# uptime; ntpq -p; ntptime 6:32AM up 6:20, 1 user, load averages: 0.03, 0.04, 0.01 remote refid st t when poll reach delay offset jitter == -pfsense.localdo 193.62.22.90 2 u 27 64 3771.3420.089 0.259 *GPS_PALISADE(0) .GPS.0 l 13 16 3770.0001.057 0.053 oPPS(0) .PPS.0 l 12 16 3770.0000.009 0.004 +ntp02.oal.ul.pt 194.117.9.1382 u 23 64 377 10.4560.584 0.312 -ntp04.oal.ul.pt 194.117.9.1372 u5 64 377 10.545 -1.559 6.550 +gatekeeper1.ist 193.204.114.232 2 u 22 64 3779.4800.673 0.228 -gatekeeper2.ist 192.93.2.20 2 u 61 64 377 11.570 -0.353 2.329 ntp_gettime() returns code 0 (OK) time d5331e7c.79288cbc Tue, May 7 2013 6:32:28.473, (.473275743), maximum error 7000 us, estimated error 1 us, TAI offset 0 ntp_adjtime() returns code 0 (OK) modes 0x0 (), offset 9.366 us, frequency 144.542 ppm, interval 256 s, maximum error 7000 us, estimated error 1 us, status 0x2107 (PLL,PPSFREQ,PPSTIME,PPSSIGNAL,NANO), time constant 4, precision 0.001 us, tolerance 496 ppm, pps frequency 144.542 ppm, stability 0.004 ppm, jitter 2.774 us, intervals 111, jitter exceeded 535, stability exceeded 1, errors 1. I still need to calibrate the PPS in order to account for the 200 feet (60 m) of cable I have between the antenna and the server. Cheers, Miguel And interresting trick is to put two or more GPS units on the same computer. then use NTP to compare. You can test out what works best and measure the differences That is a good idea. I find that in my LAN I can get two stratum 1 servers (with different brands of receivers) 5 us of each other consistently. And for NTP I believe that is good enough. Cheers, Miguel ___ 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] Imagery position accuracy
On 6 May 2013 03:21, Chris Albertson albertson.ch...@gmail.com wrote: After you get the position, how does the OP (or anyone else) put the location data into the Trimble GPS receiver so that it can be used in the time solution. This is for NTP remember. Hi Chris! You can input the information through the Windows application and tell it to not self-survey. Assuming there is some way, will the Trimble GPS receiver remember the location over a power cycle? The position as all the configuration is stored in the EPROM when one issues a command on the Windows interface. In other words, is there a way to program a Trimble receiver to NOT do the self-survey on power up and instead to use some survey location you got by some other method, like possibly hiring a survey team. Sure! If there is a why to make that work, I might even modify the NTP driver to do it. You'll have to make the driver talk to the configuration / monitoring port (port B) as the timing port (port A) does not accept commands. I thought about sending the configuration commands to port B and get the time from port A. The problem with this is that you can't raise the RTS pin to request a time packet from the receiver (they call this event something... can't remember). What I did in the end was to use two RS422-to-RS232 converters so I can use the driver normally through port A and then set the receiver and see the birds it is following on port B. I've also used the PPS+ signal and connected it to the DCD pin. Just completed this project a few minutes ago. The machine has been running for a few minutes: acutime# uptime; ntpq -p; ntptime 10:34PM up 31 mins, 1 user, load averages: 0.00, 0.00, 0.00 remote refid st t when poll reach delay offset jitter == *GPS_PALISADE(0) .GPS.0 l 12 16 3770.0001.073 0.031 oPPS(0) .PPS.0 l 10 16 3770.0000.077 0.007 ntp_gettime() returns code 0 (OK) time d532ae7f.98b1edec Mon, May 6 2013 22:34:39.596, (.596465965), maximum error 6000 us, estimated error 1 us, TAI offset 0 ntp_adjtime() returns code 0 (OK) modes 0x0 (), offset 72.469 us, frequency 143.112 ppm, interval 256 s, maximum error 6000 us, estimated error 1 us, status 0x2107 (PLL,PPSFREQ,PPSTIME,PPSSIGNAL,NANO), time constant 4, precision 0.001 us, tolerance 496 ppm, pps frequency 143.112 ppm, stability 0.234 ppm, jitter 0.663 us, intervals 29, jitter exceeded 23, stability exceeded 0, errors 3. My configuration server 127.127.29.0 mode 3 minpoll 4 maxpoll 4 prefer # Event polling (flag2 0) fudge 127.127.29.0 flag2 0 # PPS driver capture on rising (flag2 0) and kernel PPS active (flag3 1) server 127.127.22.0 minpoll 4 maxpoll 4 fudge 127.127.22.0 flag2 0 flag3 1 statsdir /var/log/ntp/ filegen peerstats file peers type day link enable filegen loopstats file loop type day link enable filegen clockstats file clock type day link enable With this configuration I can stop using the PALISADE driver and configure the Acutime to send NMEA sentences and use the PPS for better accuracy. Regards, Miguel ___ 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] GPS position survey
Hi fellow time nuts! I've recently bought a Trimble Acutime gold that will be used as a reference clock for a NTP server. This receiver has the possibility of averaging it's position before entering what Trimble calls the overdetermined clock state. The default is to average the position with 2000 fixes. What do you believe is a good number of fixes for the survey in this case? Cheers, Miguel ___ 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] GPS position survey
On 5 May 2013 11:51, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 8311230247672528820@unknownmsgid, =?ISO-8859-1?Q?Miguel_Barbosa_Go n=E7alves?= writes: This receiver has the possibility of averaging it's position before entering what Trimble calls the overdetermined clock state. The default is to average the position with 2000 fixes. What do you believe is a good number of fixes for the survey in this case? It will be enough for error detection and it will stabilize your signal somewhat, but it is not even remotely close to giving you a precise position which will attenuate the 12h wiggles from the satellite orbits. Hi Poul! So you think a full day of position survey will be better? The receiver will still output time while surveying so doing it for a long time is not a problem. Appreciate your input. Cheers, Miguel ___ 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] GPS position survey
On 5 May 2013 20:18, Chuck Forsberg WA7KGX N2469R c...@omen.com wrote: When doing a position survey, does Lady Heather have to be running? Or does the Thunderbolt do it by itself? I don't know about Thunderbolt but on my Acutime Gold the Windows software sends the restart survey command to the antenna and the antenna does everything by itself. I can even turn off the Windows monitoring software. HTH, Miguel ___ 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] nanobsd conf
On 27 April 2013 14:17, Mark C. Stephens ma...@non-stop.com.au wrote: Hi All, I am trying to get my head around building a nanobsd for some HP thinclients to run as stratum 1 servers. If you have the time, please send me an example conf file for sh nanobsd.sh -c myconf.nano I am unsure of how to add my 2 refclocks, a 29 (trimble) and a 20 (nmea+pps) Also, where do I add PPS to the kernel options? I noticed no one responded to this. I am running two FreeBSD 8.3 boxes with nanoBSD. At the moment I have two NMEA clocks and will be adding a Trimble Acutime Gold (with driver 29 and 22) soon as I am testing it at the moment. Contact me over my private mail (m...@mbg.pt) and I will help you as I can. Cheers, Miguel ___ 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] GPS position survey
On 5 May 2013 12:28, Sarah White kuze...@gmail.com wrote: I myself did a sampling over a period of 1 million samples (actually, it was a value of 2^20, not exactly 1 million) quickest it could have completed such a survey is 12+ days ... However, I had masks set for elevation, signal, etc. (resulted in occasional periods when there was no lock) Thank you Sarah for your input! I might do that. For what I've read regarding timing applications the receiver should pick only satellites with high elevation but for position surveying a good geometry is better. Could you give your input regarding elevation masks and other parameters to do a good survey? Regards, Miguel ___ 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] GPS position survey
Hi Chris! On 06/05/2013, at 01:21, Chris Albertson albertson.ch...@gmail.com wrote: If you are talking about using this with NTP. I don't know if you have a choice. The Trimble receiver is going to do whatever it is going to do when you power it up.Software running on a PC can perform a 24 hour survey and report the location but the Type 29 driver in NTP has no way to tell the Trimble receiver what to do on power up. And there is no way to specify a location you have surveyed by some other means. What I am doing at the moment is connecting Trimble's port A (timing port) to NTP and configuring the receiver using a Windows laptop through port B. I can connect to port B occasionally to check the receivers health. The receiver has its configuration stored in an EPROM so it will just work anytime unless the configuration gets corrupted. After the survey ends the position can be optionally stored to the EPROM. Also, if the antenna changes its position more than 1000 meters a new self-survey will run automatically. Perhaps the Trimble GPS has some way to program it's FLASH Rom with changed parameters but NTP only reads the packets. It does not send any. Can LH download a surveyed location r change the length of the survey? NTP can't do any of that It does. It is available on the Trmble's FTP site. Other NTP drivers such as the Type 30 Motorola driver are more flexible. Those alow you to specify a lat, long that was surveyed or have the receiver do a survey. The type-30 Motorola driver is a lot more configurable. The Trimble software is very nice and allows one thing the Motorola NTP driver doesn't allow if I remember correctly. On the Trimble I can choose the number of fixes for the survey and can watch it run while NTP is receiving time. I can't do this on an Oncore because it only has one port. But as was said, light travels about 30cm/nanosecond and NTP works in microseconds. So your location can be off by 1000 times 30cm before NTP will care. So 3 or 4 meters of location error will not matter and the 2,000 point self survey will be good enough. When surveying accuracy of the PPS will be around 1 us. The accuracy will obviously increase when the survey ends. But if yo really so want nanosecond level timing, then you need to care about the survey Agree! Cheers, Miguel ___ 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] Trimble Resolution T
Hi! I'm looking at the Resolution T from Trimble (http://www.trimble.com/timing/resolution-t.aspx). Does anyone here connected it successfully to a computer? Are the voltages compatible with RS232 or do I need some converter? Thanks! Regards, Miguel ___ 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] GLONASS receiver
On 5 August 2012 22:45, Bob Camp li...@rtty.us wrote: Hi Hi Bob! What sort of accuracy do you need? If 1 ms is good enough, then indeed a GPSDO I was looking at http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm and apparently this might work. I could connect this to one of my servers and use the PPS signal on the serial port. Anyone has experience with this product? Thanks! Cheers, Miguel On Aug 5, 2012, at 5:36 PM, Miguel Gonçalves m...@mbg.pt wrote: Hi there! I currently have 2 embedded machines connected to a Garmin 18 LVC and a Sure GPS board. They are NTP servers for my company's LAN and I, at the moment, I get sub-ms accuracy over the LAN. Everything is fine but I am a bit worried about the GPS reliability because GPS is ruled by the USA. Would a GPS disciplined oscillator solve any potential problems? A receiver for GLONASS, even though I did not find any at a reasonable price, would be better? An iridium oscillator calibrated, regularly by GPS? Too many questions... but in the end I would like to know what is the best path that I could follow after these GPS receivers. Many thanks! Regards, Miguel ___ 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.
