(This is for Adam and Andrew)
APM 2.0, 3DR quad, ~ 1300-1650grams (depending on payload and battery), 750kv motors, 11x4.7 SF props, 3s, v2.5.3
1) Log file of mag and yaw difference using tlog method of mag calibration
2) tlog file used for calibration
3) log file of flight with nominal mag and yaw difference (live data method for calibration
See the difference? Maybe just a bad tlog? Btw, how can I look at the tlog? Loading via mission planner and playing it back seems to do nothing.
Also, this may or may not be related, but I had a long flight today with the go pro. Looking at the log file, the mag seems to drop out completely randomly. It flew pretty well, and only a few times did yaw feel sloppy. I tried loiter (needs tuning) and alt hold (ch6 tuning attempt) but mostly flew stable and simple.
Another oddity of this flight happens about a third of the way in, my quad had a uncommanded roll which ended in a crash. Fortunately, I was about 3 ft above the ground and did not damage anything. I flew fine after this with no issues. Any thoughts as to what caused this?
Jonathan... I don't see any flying in that tlog. That is most likely the problem.
Hmm.. well that would be the a big red flag! I was sure that was a flight tlog.. hmm.
Are tlogs generated for each flight, like the .log files? I don't have wireless telemetry, so i have to download files after each flight.
tlogs require that telemetry is enabled. If you are feeling courageous you could pull the latest from git trunk and use the new in-flight compass calibration. People who have tested it thus far have had very good results.
Gotcha. That makes sense.
I was thinking about it. Maybe tomorrow :)
What do you think about that other log i posted (2.7 mb one)? The mag seems to drop out completely randomly. I haven't seen that before. Yaw didn't seem affected much though i did have an uncommanded roll. Not sure if that was related.
I didn't have time to take a look at the longer log, but with an uncalibrated compass as yours was, all sorts of strange things can happen. The heading and attitude solutions are intertwined so the uncommanded roll doesn't surprise me. Good luck!
Good point. I will look into a bit more.
About your in-flight compass cal, does it help with magnetic interference we are seeing form the motors? I know that with the 2.5+ firmwares, the DCM is more sensitive to magnetic interference when it comes to yawing (at least that's how i understand it). I am assuming that the in-flight cal takes looks at the motor induced offset as well, correct?
Thanks for all of the help!
The in-flight compass cal is thanks to Bill Premarlani and Andrew Tridgell... It attempts to model the offsets for the amount of motor noise that your frame has. So in a way, yes.