Kevin, I am very interested in your GNSS monitoring website. I would consider building a system similar to yours, perhaps using dual frequency receivers. I am not exactly in 'another part of the world' (though it often seems another planet) in central Missouri at 38.947232, -92.303583. I would like to know more about your setup. Dave

Hi Dave, Great! We were hoping that more people would set up similar sites as well, so I am glad to see interest. The only outstanding issue with the website is the data collection. The library I used for the U-blox UBX protocol frankly sucks, and was a major source of issues. As such, messages are occasionally dropped and lost. I would highly recommend picking receivers that have well tested and supported libraries so you do not run into this issue. There's a diagram on the About Us page that shows how the system works, here's a direct link: https://gnssperformancemonitor.com/images/architecture.png There are 4 major subsystems: 1. Data Collection 2. Job Scheduler 3. Data Plotting 4. Website Data is collected and stored in a MySQL/MariaDB database (the database schema is virtually identical to what you get from the datadownload page). A job scheduler runs at multiple regular intervals and runs plotting scripts which fetch data from the database using SQL queries. The data plotter uses matplotlib as a backend to generate png images (and ffmpeg to generate the daily MP4 videos: https://gnssperformancemonitor.com/images/1Day/GPS/GPS_1Day.mp4), which are stored in a directory accessible by the web server. The website uses PHP as a templating language essentially to build the pages, since all that's really changing on each page is links to images (constellation name, timespan). I have uploaded a PDF of our Final Design Review that I presented to my class at the end of last semester, it has a lot of information on implementation and such. See here: https://gnssperformancemonitor.com/time-nuts/Final_Design_Review.pdf Additionally, a pic of the data collection system: https://gnssperformancemonitor.com/time-nuts/datacollection.png Fortunately/unfortunately, I am about to start my EE Masters program, so I am very short on time for more projects. I am currently just maintaining the website, and not adding new features. I don't currently have plans to open source my code but that may change in the future if there is significant interest. Best, Kevin On Sat, Jul 13, 2019 at 1:38 PM David Witten <wittend@wwrinc.com> wrote: > Kevin, > > I am very interested in your GNSS monitoring website. I would consider > building a system similar to yours, perhaps using dual frequency > receivers. I am not exactly in 'another part of the world' (though it > often seems another planet) in central Missouri at 38.947232, -92.303583. > I would like to know more about your setup. > > Dave > -- Kevin Croissant

-------- In message <CAJPH7-etp5zKcW7-sCNogv9o0=fatPHvd1eZR70OBtP9dv9pYA@mail.gmail.com> , Kevin Croissant writes: >Great! We were hoping that more people would set up similar sites as well, >so I am glad to see interest. >The only outstanding issue with the website is the data collection. The >library I used for the U-blox UBX protocol frankly sucks, and was a major >source of issues. The gpsd software has what looks like a moderately competent python library for UBX. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

We monitor GNSS timing in this way ie with common, single-frequency receivers configured to track a single GNSS system only, measured with respect to UTC(AUS). The plan was to make the data publicly available but that's still on the TODO. Currently we monitor GPS, GLONASS and BeiDou. Over the two years or so we've been doing this, I've noticed multiple problems with receiver loss of tracking, even when many SVs are visible and useable, and lockups when tracking non-GPS signals. I attribute this to bugs in the receiver firmware, rather than the GNSS. There is of course a vast amount of data available already through the many IGS stations reporting multi-GNSS data, just not in a convenient form. Cheers Michael