[time-nuts] Galileo service currently degraded

[Kevin Croissant]

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 at 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