Ok, that’s good. That means that mavlink-router is routing the telemetry from the serial port to over udp.
What commands? The apsync img file is preconfigured. No extra commands are required.
You don’t need to use the --baud option when using a udp source
Generally, you should only run as root when making system modifications that require it.
Looking at the Communicating with Raspberry Pi via MAVLink — Dev documentation, those instructions are quite old and probably don’t work anymore. They need updating (thanks for pointing that out!). Hopefully I’ll have some time over the Christmas break to update them.
Rpanion is a completely different software with a different img file to download and install. You can have Rpanion or Apsync running on your Pi, not both.
Oops, that was a typo. I meant the SERIAL1_PROTOCOL (set to 2)
APSync uses mavlink-router to distribute the telemetry, and is already set to auto-start in the imgfile. You don’t need to use MAVProxy for that.