Friday, October 30, 2015

Tria GPS Success in the REF-0

I made some good progress yesterday on the Tria GPS firmware. I have been finding and fixing little bugs over the past few days, and finally got to the point where I could test my Oncore message formatting routine. This is an entirely new chunk of code that creates Oncore message strings in real-time using data sent from the U-blox GPS. That is a very different approach from my previous REF-0 standalone techniques, which used canned strings to make a REF-0 lock up. I am now sending real data in all of the messages, including SV info, position, date/time, and configuration settings.

I dropped the Tria GPS into a REF-0 and launched SatStat to view the status screen. To my slight surprise, nearly everything was populated correctly. I had to make some minor adjustments, but the new Oncore message formatting routine is a success. Here's a screen capture of SatStat for the REF-0 with the Tria GPS:

Status Screen for a REF-0 with the Tria GPS

The SV info is little wonky. Partly that is because I have to adapt satellite info for a 16 channel receiver to 8- and 12-channel messages. I plan to do some more sorting to ensure that the top 12 SVs that the U-blox has acquired appear in the status screen of the GPSDO.

With my message formatting routine working, I am closer to the end goal of full Oncore compatibility. I now need to write some code to allow the GPSDO to send commands to the Tria GPS and configure it. Once that is done, I will be able to make a REF-1 lock up using the new GPS. That will be exciting.

Thanks for reading!

- Dan W.


  1. Dan,
    Nice progress. The uBlox module is a nice technology upgrade (faster tracking) as well as supporting the future European and Chinese constellations, for global users.

  2. WoW, Dan, Well done. I really like the "real" messages rather than the canned ones. This is going to be a great addition to the REF-0. I'm looking forward to your continued optimization. Thanks for sharing.

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  4. Suggestion, for the "sort to narrow 16 to 8-12".
    1. You can adjust the elevation mask (10 degree), as a satellite filter.
    2. You can "filter out" satellites that are descending (toward local horizon) below a specific elevation.

    1. I did consider a system that complex, but I opted for a simple sorting routine. While you can view SV info in SatStat or some other similar program, you also have u-center as a new option. It gives you far more information about GPS status in a much more modern interface. And you literally just plug in a USB cable, no RS-422 to worry about.

  5. Hi Dan, any progress updates on Tria & Denuo?