We use a Herelink air unit on a multirotor. The air unit connects to a Linux companion computer over
Ethernet and to the flight controller over SBUS.
We are chasing intermittent RC dropouts that we see somewhat regularly — varying durations, from a few seconds up to ~12 s. On the aircraft side all we can see is SBUS frame decode status going to zero (no valid frame decoded for 200 ms) and then recovering. Bench testing ruled out plain RF loss: forcing an RF interruption between ground unit and air unit produces a different signature than what we see in flight. power related issues were also ruled out.
So everything points at the air unit itself, and that is where our visibility ends. What we would like is a way to see what the air unit was doing during those windows.
Questions
- Is there any persistent logging on the air unit? We can get a shell via adb, but we have not
found a log that survives a reboot, or a reliable way to tell whether the unit restarted at all. - Is there a debug or verbose logging mode that can be enabled — for the radio stack, the SBUS output path, or the link manager?
- Which logcat tags are worth watching? Anything we can leave running and dump after a flight wouldalready help a lot.
Goal is simply to correlate an air unit event with the dropout we see on the aircraft. Any pointers
on how to instrument the air unit appreciated