Help me figure out why the M2P crashed ?
- Thread starter Dakrisht
- Start date
It's very simple - if the aircraft direction indicator is correct at takeoff then there will not be any magnetic problems during the flight - unless you subsequently fly the aircraft too close to a large magnetized steel or iron structure, such as a bridge, ship, tank etc.
Local government or private developers. No difference. No metal fabric used in this area for sidewalks. Floors for homes and commercial work is totally different. They use it all the time.
My P3 went crazy for about a minute after something like 10 min in flight, over 100' up, clear air. Launched from grass. Got compass error a few seconds after going crazy, went into atti. It cleared up though.
I've often thought (and said once or twice) that DJI could handle mid-flight compass issues better when GPS is OK. If compass, IMU and GPS disagree, disregard compass. GPS delta will provide reasonably accurate heading. From that it can offset the compass error and resume using it.
I've often thought (and said once or twice) that DJI could handle mid-flight compass issues better when GPS is OK. If compass, IMU and GPS disagree, disregard compass. GPS delta will provide reasonably accurate heading. From that it can offset the compass error and resume using it.
GPS gives no heading information. If by heading you mean track, then that's no use to the aircraft in determining which direction it is facing. It needs both for positional control.
A better choice would be to use the compass data instead. In almost all of these incidents bad compass data was the initial cause but it's correct by the time the FC figures out there is a problem. The FC can't know which is correct though. IMHO the best strategy is to switch to ATTI mode and let the pilot do the navigating.
And also continue to show GPS position on the map and recorded in the log - since that is almost never incorrect.
So, here is what I learned from this thread. Please correct me if I am wrong:
1. If you get a magnetic interference message/warning, always move to a different location and see if it goes away. Only perform a compass calibration if the message persists after moving to a new location (preferably, one where you are reasonably confident that there are no causes for a magnetic interference)
2. The Go4 app may not always warn you about possible magnetic interference. Always check the orientation of the aircraft in the map matches its physical orientation on the ground. If the two don't match it means there is a magnetic interference issue but the app is not telling you about it. If this happens, follow step one above.
3. When uncertain about the makeup of the ground beneath your feet, a hand launch will be the safer option.
4. In the unlikely event that you did all these and your aircraft suffered a catastrophic magnetic interference error and spins out of control, there is really not much you can do to contain or overcome this catastrophe. Just watch it as it unfolds.
1. If you get a magnetic interference message/warning, always move to a different location and see if it goes away. Only perform a compass calibration if the message persists after moving to a new location (preferably, one where you are reasonably confident that there are no causes for a magnetic interference)
2. The Go4 app may not always warn you about possible magnetic interference. Always check the orientation of the aircraft in the map matches its physical orientation on the ground. If the two don't match it means there is a magnetic interference issue but the app is not telling you about it. If this happens, follow step one above.
3. When uncertain about the makeup of the ground beneath your feet, a hand launch will be the safer option.
4. In the unlikely event that you did all these and your aircraft suffered a catastrophic magnetic interference error and spins out of control, there is really not much you can do to contain or overcome this catastrophe. Just watch it as it unfolds.
Texbow
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I think we are saying the same thing. Your not suggesting that if I have a notice to calibrate in addition to the magnetic interference that I ignore that message?
In the event of (4) - immediately switch to ATTI mode, if you have enabled it.
I’d correct with:
1. You don’t need to calibrate ever accept for the first time out of the box or if you travel long distances such as 200-300 miles away. Although from the video above, newer DJI drones have lookup tables so they actually know you’ve traveled and can correct for compass variation.
As others have said, calibration isn’t necessary at all, just moving away from the mag interference is what it takes.
The Mavic 2 prompts for calibration if you move more than 50 km from the last flight or if it is more than 30 days from the previous calibration. And it's nothing to do with the aircraft needing to know the variation - all the current DJI aircraft have built-in global magnetic field models, and calculate variation and inclination as soon as they acquire a position.
I don't know about that. I have had the Mavic Air throw up a magnetic interferance error while trying to take off in the middle of farms. No nearby power lines, nothing I could put my finger on as the source of the interference. I moved several meters, still same error. Moved again and restarted everyithing, same error. Took off my watch and put it far far away, same error. I even emptied my pockets of any change and keys and tried again. It won't go away. After several attempts, I failed to understand what it wanted and gave in. I calibrated the compass and it flew fine.
That may be a case where the magnetization of something on the aircraft had changed, and it really did need recalibration. Or maybe the MA now requests periodic or distance-based recalibration. The DAT file would show the reason in the event stream.
It definitely was not distance related in my case. But it could have been a periodic thing. But all in all, I think the MA is a bit temperamental when it comes to its compass. In the four months I have had it, it has asked me to re-calibrate the compass three times already (not counting the first out of the box calibration).
A notice to calibrate and a magnetic interference warning?
I think you are confusing one message and thinking of two.
Here's a screenshot of the warning message when I put my drone on the car roof with the compass right on top of steel.
It scrolls across the message box as it's too long to display.
It says: Magnetic Field Interference Move aircraft or calibrate compass.
99% of the time you see that message, the correct action is to move the drone away from the steel it's warning you about.
Texbow
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I understand what your saying now. I was thinking about the calibrate compass message on initial start up of the remote and drone. The one I get when I travel between inspection locations.A notice to calibrate and a magnetic interference warning?
I think you are confusing one message and thinking of two.
Here's a screenshot of the warning message when I put my drone on the car roof with the compass right on top of steel.
It scrolls across the message box as it's too long to display.
It says: Magnetic Field Interference Move aircraft or calibrate compass.
99% of the time you see that message, the correct action is to move the drone away from the steel it's warning you about.
I assume it would be better if the message didn’t have ‘or calibrate ‘.
Agreed - the messages could certainly be clearer on what is triggering the request.
Magnetic interference should trigger a pop up similar to a high wind warning. Someone at DJI needs to hear this feedback.
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