I recently purchased two MT3329 modules for use on an APRS tracker, which I'd like to be able to use for high altitude balloon tracking. I tested one of the modules on the GPS simulator today and found that it cut off serial data at just over 60k feet; indicating that the max altitude/velocity limit is an OR relation (stops working if either is exceeded). Furthermore, the fact that the UART stops sending data as opposed to loses lock is a bit worrying as well, I did not check to see if it came back on after dropping below 60k feet. This could cause issues for applications relying on the GPS as a real-time clock, as I've done in some of my projects. I am wondering if it would be possible for DIYDrones to request a firmware that allows continued use of the GPS over 60k feet (change restriction to AND relation, as it should be).
I'm hoping to hear an answer on this too. I'm wanting to use the APM to guide a balloon-dropped glider back to the launch point or to a remote touchdown site. Basically high-altitude balloon payload that navigates its way home. So I need an APM that will function at ~100k ft.
The Garmin 18x works above 60000 feet. We have flow it without issues on two occasions to over 100000 feet. The last flight was to over 126000. There are a few other units that have also been found to work. You will need to search online. There was an amateur radio HAB site that listed units that worked but I no longer have the address and I don't know if its still around or if its been updated.
Hope this helps
rstriemer AT pembinatrails.ca
Great info, Rob. Thanks. Also, congratulations on your altitude achievement!
Here's a site listing GPS modules that work above 60k feet: http://showcase.netins.net/web/wallio/GPSrcvrsvs60kft.htm
I've used and tested this GPS to work above 60k feet: https://www.argentdata.com/catalog/product_info.php?cPath=23&pr...
I would still very much like to see a high altitude firmware specifically for the MT3329, since it's so small and light (weight is certainly an issue for HAB flights, unless balloon size/money isn't an issue).
- Justin, KJ6KST
See this post here (at the end)
The UKHAS regularly fly uBLOX and Lassen modules in excess of 40km.