Hello Time-Nuts, Wishing all a very Happy New Year! Just wanted to make the list aware of a very nice tool that I have discovered. I have been playing around with common view GPS observations to compare my house reference to NIST. USNO and AMCT also produce their CGGTTS files, but their web page is down for reconstruction. Coming up the learning curve has soaked up waayy too many hours, but the results have been gratifying. CGGTTS files are in ASCII format and are produced for each station so that GNSS satellites that are in common view can be used to compare their clocks. NIST publishes their file daily, you can check out tf.nist.gov/NIST_GPS/NIST_.gps to see what the file looks like. Producing the CGGTTS file for your local site can be interesting. I drive a Trimble NetRS with my house reference, produce .T00 files, process them with Trimble convertToRinex, then use R2CGGTTS to generate my CGGTTS file. I have written a Python program that goes out and grabs all the data, does all the file processing, and prepares the NIST and local CGGTTS files for analysis. This is where the really neat tool comes in. BIPM and IEEE have written a tool that runs on a web browser to compare the CGGTTS files. The software is on github at - GitHub - TheBIPM/CCTF_CBKT_software <https://github.com/TheBIPM/CCTF_CBKT_software> . It will take one (or more) CGGTTS files for two stations and plot the individual station clocks as well as the differenced common view solution. It also produces csv files of the data (though they use tab instead of comma, so you have to rename it something besides csv to get it into Excel). One really nice feature of this is that you are comparing to UTC(nist) directly, instead of UTC(gps). I have attached a couple of screenshots of the (partial) output. Enjoy. I hope to publish some data in the relatively near future of this work and comparisons to three other GPS receivers. Regards, Skip Withrow

Hi At least according to this: http://www.openttp.org/downloads/MosaicT_IFCS-EFTF_2021_paper.pdf The Mosaic-T will also “play nice” with CGGTTS files as an output. Are there “tangles” in the generation process? I don’t (yet) know. It *appears* that the “stock” firmware and support software handles their generation. It appears that the modern uBlox stuff can do CGGTTS. A quick search suggests the generation process is a bit complex. It looks like a log the raw data and convert from there with this or that sofware sort of process. Bob > On Jan 7, 2026, at 6:28 PM, Skip Withrow via time-nuts <time-nuts@lists.febo.com> wrote: > > Hello Time-Nuts, > Wishing all a very Happy New Year! > > Just wanted to make the list aware of a very nice tool that I have > discovered. I have been playing around with common view GPS observations > to compare my house reference to NIST. USNO and AMCT also produce their > CGGTTS files, but their web page is down for reconstruction. Coming up the > learning curve has soaked up waayy too many hours, but the results have > been gratifying. > > CGGTTS files are in ASCII format and are produced for each station so that > GNSS satellites that are in common view can be used to compare their > clocks. NIST publishes their file daily, you can check out > tf.nist.gov/NIST_GPS/NIST_.gps to see what the file looks like. > > Producing the CGGTTS file for your local site can be interesting. I > drive a Trimble NetRS with my house reference, produce .T00 files, process > them with Trimble convertToRinex, then use R2CGGTTS to generate my CGGTTS > file. I have written a Python program that goes out and grabs all the > data, does all the file processing, and prepares the NIST and local CGGTTS > files for analysis. > > This is where the really neat tool comes in. BIPM and IEEE have written a > tool that runs on a web browser to compare the CGGTTS files. The software > is on github at - GitHub - TheBIPM/CCTF_CBKT_software > <https://github.com/TheBIPM/CCTF_CBKT_software> . It will take one (or > more) CGGTTS files for two stations and plot the individual station clocks > as well as the differenced common view solution. It also produces csv > files of the data (though they use tab instead of comma, so you have to > rename it something besides csv to get it into Excel). > > One really nice feature of this is that you are comparing to UTC(nist) > directly, instead of UTC(gps). I have attached a couple of screenshots of > the (partial) output. Enjoy. I hope to publish some data in the > relatively near future of this work and comparisons to three other GPS > receivers. > > Regards, > Skip Withrow > <CGGTTS_Analyser_1.png><CGGTTS_Analyser_2.png>_______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Yes, the Septentrio PolaRx5-T and Mosaic-T will both produce CGGTTS files natively. You can check out their manuals on how to set it up. The Mosaic-T does need an authorization code to enable external reference input (plus the hardware hooks in place). Anybody know how much it costs, and is it one time only or subscription? The PolaRx5-TR has an external clock input, but new from the factory I think they are in the $15k range. Otherwise, any receiver that will produce a RINEX format file (and preferably has external clock input) can be used. The RINEX files are processed with R2CGGTTS to produce the CGGTTS file. There are a few twists and turns in this process, but once figured out it is quite straightforward. I'm willing to share notes with those interested. You can even get CGGTTS files from a receiver that does not have an external clock reference IF you add an external time interval counter. There is a project on github called OpenTTP that does this - GitHub - openttp/openttp: A platform for traceable time and frequency <https://github.com/openttp/openttp> It can use several different receivers and counters, the Ublox F9T with TICC looks attractive. However, I have not attempted this project (some software assembly required). Skip Withrow On Thu, Jan 8, 2026 at 10:36 AM Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > At least according to this: > > http://www.openttp.org/downloads/MosaicT_IFCS-EFTF_2021_paper.pdf > > The Mosaic-T will also “play nice” with CGGTTS files as an output. Are > there “tangles” in the generation process? I don’t (yet) know. It *appears* > that the “stock” firmware and support software handles their generation. > > It appears that the modern uBlox stuff can do CGGTTS. A quick search > suggests the generation process is a bit complex. It looks like a log the > raw data and convert from there with this or that sofware sort of process. > > Bob > > On Jan 7, 2026, at 6:28 PM, Skip Withrow via time-nuts < > time-nuts@lists.febo.com> wrote: > > Hello Time-Nuts, > Wishing all a very Happy New Year! > > Just wanted to make the list aware of a very nice tool that I have > discovered. I have been playing around with common view GPS observations > to compare my house reference to NIST. USNO and AMCT also produce their > CGGTTS files, but their web page is down for reconstruction. Coming up the > learning curve has soaked up waayy too many hours, but the results have > been gratifying. > > CGGTTS files are in ASCII format and are produced for each station so that > GNSS satellites that are in common view can be used to compare their > clocks. NIST publishes their file daily, you can check out > tf.nist.gov/NIST_GPS/NIST_.gps to see what the file looks like. > > Producing the CGGTTS file for your local site can be interesting. I > drive a Trimble NetRS with my house reference, produce .T00 files, process > them with Trimble convertToRinex, then use R2CGGTTS to generate my CGGTTS > file. I have written a Python program that goes out and grabs all the > data, does all the file processing, and prepares the NIST and local CGGTTS > files for analysis. > > This is where the really neat tool comes in. BIPM and IEEE have written a > tool that runs on a web browser to compare the CGGTTS files. The software > is on github at - GitHub - TheBIPM/CCTF_CBKT_software > <https://github.com/TheBIPM/CCTF_CBKT_software> . It will take one (or > more) CGGTTS files for two stations and plot the individual station clocks > as well as the differenced common view solution. It also produces csv > files of the data (though they use tab instead of comma, so you have to > rename it something besides csv to get it into Excel). > > One really nice feature of this is that you are comparing to UTC(nist) > directly, instead of UTC(gps). I have attached a couple of screenshots of > the (partial) output. Enjoy. I hope to publish some data in the > relatively near future of this work and comparisons to three other GPS > receivers. > > Regards, > Skip Withrow > <CGGTTS_Analyser_1.png><CGGTTS_Analyser_2.png> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com > > >

Hi I can find very little about CGGTTS in the Mosaic-T manuals I have. Most of what I can find routes me to the Septentrio RX Tools software. It appears to simply be doing about the “same thing” as R2CGGTTS. Looking at the “Permitted Capabilities” list on a typical Mosaic-T: Frequency Sync is enabled Time Sync is enabled Event Tracking is enabled That and a lot of other stuff are all enabled by default. The main stuff that is disabled by default is pretty much all moving base / DGNSS / RTK related. My understanding is that the CPU isn’t up to doing full RTK on top of the fancy timing work. I could easily be wrong …. Any hints on docs for onboard CGGTTS for the Mosiac-T (as opposed to the PolaRx5)? Bob > On Jan 8, 2026, at 3:43 PM, Skip Withrow <skip.withrow@gmail.com> wrote: > > Yes, the Septentrio PolaRx5-T and Mosaic-T will both produce CGGTTS files natively. You can check out their manuals on how to set it up. The Mosaic-T does need an authorization code to enable external reference input (plus the hardware hooks in place). Anybody know how much it costs, and is it one time only or subscription? The PolaRx5-TR has an external clock input, but new from the factory I think they are in the $15k range. > > Otherwise, any receiver that will produce a RINEX format file (and preferably has external clock input) can be used. The RINEX files are processed with R2CGGTTS to produce the CGGTTS file. There are a few twists and turns in this process, but once figured out it is quite straightforward. I'm willing to share notes with those interested. > > You can even get CGGTTS files from a receiver that does not have an external clock reference IF you add an external time interval counter. There is a project on github called OpenTTP that does this - GitHub - openttp/openttp: A platform for traceable time and frequency <https://github.com/openttp/openttp> It can use several different receivers and counters, the Ublox F9T with TICC looks attractive. However, I have not attempted this project (some software assembly required). > > Skip Withrow > > On Thu, Jan 8, 2026 at 10:36 AM Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote: >> Hi >> >> At least according to this: >> >> http://www.openttp.org/downloads/MosaicT_IFCS-EFTF_2021_paper.pdf >> >> The Mosaic-T will also “play nice” with CGGTTS files as an output. Are there “tangles” in the generation process? I don’t (yet) know. It *appears* that the “stock” firmware and support software handles their generation. >> >> It appears that the modern uBlox stuff can do CGGTTS. A quick search suggests the generation process is a bit complex. It looks like a log the raw data and convert from there with this or that sofware sort of process. >> >> Bob >> >>> On Jan 7, 2026, at 6:28 PM, Skip Withrow via time-nuts <time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: >>> >>> Hello Time-Nuts, >>> Wishing all a very Happy New Year! >>> >>> Just wanted to make the list aware of a very nice tool that I have >>> discovered. I have been playing around with common view GPS observations >>> to compare my house reference to NIST. USNO and AMCT also produce their >>> CGGTTS files, but their web page is down for reconstruction. Coming up the >>> learning curve has soaked up waayy too many hours, but the results have >>> been gratifying. >>> >>> CGGTTS files are in ASCII format and are produced for each station so that >>> GNSS satellites that are in common view can be used to compare their >>> clocks. NIST publishes their file daily, you can check out >>> tf.nist.gov/NIST_GPS/NIST_.gps <http://tf.nist.gov/NIST_GPS/NIST_.gps> to see what the file looks like. >>> >>> Producing the CGGTTS file for your local site can be interesting. I >>> drive a Trimble NetRS with my house reference, produce .T00 files, process >>> them with Trimble convertToRinex, then use R2CGGTTS to generate my CGGTTS >>> file. I have written a Python program that goes out and grabs all the >>> data, does all the file processing, and prepares the NIST and local CGGTTS >>> files for analysis. >>> >>> This is where the really neat tool comes in. BIPM and IEEE have written a >>> tool that runs on a web browser to compare the CGGTTS files. The software >>> is on github at - GitHub - TheBIPM/CCTF_CBKT_software >>> <https://github.com/TheBIPM/CCTF_CBKT_software> . It will take one (or >>> more) CGGTTS files for two stations and plot the individual station clocks >>> as well as the differenced common view solution. It also produces csv >>> files of the data (though they use tab instead of comma, so you have to >>> rename it something besides csv to get it into Excel). >>> >>> One really nice feature of this is that you are comparing to UTC(nist) >>> directly, instead of UTC(gps). I have attached a couple of screenshots of >>> the (partial) output. Enjoy. I hope to publish some data in the >>> relatively near future of this work and comparisons to three other GPS >>> receivers. >>> >>> Regards, >>> Skip Withrow >>> <CGGTTS_Analyser_1.png><CGGTTS_Analyser_2.png>_______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com> >>> To unsubscribe send an email to time-nuts-leave@lists.febo.com <mailto:time-nuts-leave@lists.febo.com>