I was able to use COMPASS_LEARN=3 for “In-Flight Learning” - here’s my report:
The process started almost immediately after taking off in Alt-Hold - and the Here-3 LED lights flashed blue and red during the process.
The MavLink messages reported by Yaapu telemetry were helpful and informative - reporting calibration progress 3 or 4 times as the learning process continued. Finally - after about 3 or 4 minutes - a MavLink message reported it had completed.
The process set one parameter out of range: COMPASS_OFS_Z. The MavExplorer MagFit utility has always been reporting that this parameter should be about 500 on this copter - and the range only goes up to 400. Mission Planner issues a severe caution about exceeding this parameter - but will allow it. I’ve never set it beyond the published range. I’m curious to see if it makes any different tomorrow on a test mission flight or loiters.
The only parameters that appeared to have been updated were the COMPASS_OFSxxxx parameters. There were no changes to COMPASS_DIAxxx, COMPASS_ODIxxx or COMPASS_MOTxxx.
I don’t know if these parameters were unchanged because their values (from MagFit) were already OK - or if the “In-Flight Learn” process does not include them. Until I can find out, I’ll still need to run MagFit to ensure all the compass calibration parameters are set properly.