Hi all,
I’m new in this forum and found it because of the first issue with my two weeks old Mavic Pro. I already did several flights without any problems.
Yesterday I first was flying a bit from one position. Then before changing to the next battery, I did a compass calibration because I was receiving errors in the area I was taking off (moving did improve, but one compass was nearly constant at above 900). I did the calibration in an open area with no concrete or metal close by, then moved back to the previous take-off location, changed the battery and took off. Right after I was in the air the drone was starting to hover to the right (probably with the wind) and was hard to steer back. In my panic, I was not really checking for warning signs but more focusing on getting it safely back to ground (the place was really shitty for such a problem).
I was reading a bit about this behavior and believe that either the place for the calibration was bad or I did something wrong during calibration, but I wanted someone else more experienced probably to review it to be sure. I uploaded the flight log to Phantom-Help: LINK
If you need the Dat file as well I can provide a dropbox link. The confusing thing for me is, that it was all the time in P-GPS mode and still hovered away. Most of the other issues I was reading about were where the drone was switching to ATTI mode.
Most importantly what should be the next steps before the next flight. Generally a new compass calibration in a place really free from magnetic distractions. Should I recalibrate the IMU as well? I’m kinda scared because I’m living close to the beach and probably flying pretty much above water.
Before taking off again (or from any new location), do these checks to make sure the compass is not being negatively affected by some type of external magnetic force. If you see any of those issues, you should take off from a different location.
It would be very hard (likely impossible) to calibrate the compass when it’s being negatively affected by some type of external magnetic force. So, if the compass calibration ever fails, you should move to a different location and calibrate again. Also, be sure that you don’t have any type of magnetic metal objects on your person (like on your wrists) while calibrating the compass. Anything within about 5 feet of the drone could interfere with the compass.
As for calibrating the compass in general, check out the DJI Mavic Compass Calibration Guide. It contains everything you need to know about calibrating the compass on the Mavic.
No. A bad IMU calibration will not cause compass errors like those in your flight log above.
Maybe take a test flight in a wide open location (that’s not near the water) so you have enough space to ensure all is in working order.
Thank you msinger for the useful tips and recommendations for the next flight. Do you have any idea about it staying in P-GPS mode and still behaving so strange or is this already explained because of the Compass error referring to the log?
DJI drones don’t use the GPS data when the compass is not functioning properly. They’ll drift with the wind instead of holding their horizontal position.
I’m not sure why the name of the current flight mode doesn’t instantly switch as soon as the GPS data is no longer being used.
I’ve had similar behavior with a P2. Plenty of satellites and yet it was drifting - A LOT - in one direction - not TBE. Calibrating the compass didn’t help. Calibrating the IMU didn’t help. Turned out it was a bad flight controller (master controller). Replacing it solved the problem. Disclaimer: I don’t own a Mavic.