I notice and and time again that project documentation can be either outdated or the components one uses are just ever so slightly different to work out of the box. There are always some issues that require additional googling - especially on the second build where everything should just work, right? I mean, you built it already, so it must be easy! It's not. URL are lost, commands have been forgotten and many of the important steps are missed. I document, to help myself :) But I'm also happy if someone else finds this information somewhat useful, too.
According to this, a build script can be used to set up fresh Raspberry Pi OS Lite 64bit to become a fresh, compiled from source, Stratux. That is appealing for many reasons, one of which is that I might be able to add functionality like supporting different GPS baudrates and modules. One can have dreams!
The first hurdle is to find the Raspberry Pi OS Lite 64 Bit version of the older Buster. It's here. Download the file called:
Unfortunately, the documentation is currently already confusing. At the top of the page it simply states "fresh 64bit RasPiOS Lite Image", further down then "latest 64bit RasPiOS Lite Image" and then a little later: "please use these scripts with caution and only on a fresh Raspbian Buster Image"
¯\(°_o)/¯
It is things like these... ༼つಠ益ಠ༽つ ─=≡ΣO))
Following the rest of the instructions yields a running script. It's currently installing all the dependencies. Let's see how this goes.
Either choose EU version or US version for your location. I chose US but I don't know what other than the wifi frequencies are actually different. The SDR Radios I purchased have tuned antennas. Maybe the EU ADSB runs different frequencies? I doubt it.
2
Enable persistent logging to SD card (and with that unlocking write access to the SD card)
One thing I find really strange is the way the SD card is being setup. For a device like this, it's good to have the SD card mounted as ReadOnly. However, this should be pointed out in huge letters on on the front page because not everyone is a Linux expert and knows why something like apt install fails.
By default, the SD card only offers about 200MB of storage for installing software. That maxed out during my very first attempt to get GPS running. Searching lots of github issues and reddit, I finally had the steps together to get this to work:
Go to the main page
(sorry for the washed out screenshot [it's an issue with HDR in Windows or Chrome and taking screenshots]) and click on the build number in the center at the top a bunch of times in rapid fire until something pops up indicating "Developer Mode" was enabled.
Then, go to the Settings tab and be amazed about all the new settings that showed up.
At the bottom right, there is Diagnostics. At the very bottom, check Persistent Logging:
Now reboot. The file system will now be mounted as Read/Write. This is way less safe in terms if SD card data corruption but it will allow you to install mandatory software to get the system to work. I suppose it's a good idea to turn this back off after you're done. I have yet to confirm that this will, in fact, reset the SD card to read-only.
3
GPS via 3.3V UART on the Raspberry Pi 3 40-pin header
Follow the instructions for GPS on the Pi 3 from here for any UBLOX GPS receiver. The two I have are NEO-M6 based and both work on 3.3V. Do not connect the power pin on the GPS module to 5V as it makes its GPIOs also 5V which in turn will damage the raspberry pi.