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Compass failure, mavic still in P-GPS and crash.

villasoftware

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Hello to everybody,
just came from a bad experience with mavic pro.

I've recalibrate the compass just before flight and after 2 seconds after take off the mavic has a compass error BUT still in P-GPS mode and became ungovernable and crash.

The question is WHY the mavic still in P-GPS mode with compass error and didn't switch to ATTI mode.

Any one has the same experience ?
 

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Flawless

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I'm not an expert, but from what I can tell it's likely a "bad" calibration that was in range of ferrous material or an E.M. field. As soon as it left the area of influence, compasses were no longer "calibrated".

From your location, it could have been something under the road like cables or piping/conduit or reinforcing material.

Compasses govern heading, GPS governs position. The drone cannot infer heading from GPS, only direction of travel. Barring any serious malfunction, GPS mode will not be lost as long as satellite lock remains.

(This is also why calibration should be done in a known "safe" space, and not performed in the field before every flight - you raise the chance exponentially of interference causing a "bad" calibration).
 
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villasoftware

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Seems exactly what happen to my pour mavic, he start to be ungovernable and crash.
There is any procedure that you can suggest to follow when the compass calibration or immu is needed, meant some manual that explain when and when not do any kind of calibration and where to learn this lesson.
Any handled instruments thath we can use to inspect the location before flight (kind of interference measurement tool).

Thank you really for your answare, i've bought a second mavic, it is fantastic, the experience of flight is so nice.

This time i've got also the dji care, but really wish to learn somethings more and don't use it

Best regards.
 

villasoftware

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Hello, some bad news about mavic product.
I reach to fix the leg of my crashed drone due compass error, reach a veri big green field (where also my new mavi flight witouth problem), i did the compass recalibrate, and try to flight......... i got again compass error and the mavic crash again.

I believe now is clear this mavic has a compass issue from beginning, the effect was the same of beginning, he start and after short time he keep rotare on hisself and crash.

Any othe one has the same problem with the compass ???

Best regards.
 

Cut.Aussie

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People really need to stop propagating this false idea that you have to constantly calibrate the compass before every days flying.
It’s simply not necessary EVER unless the app tells you.
The risk of a bad cal is not worth it
 

BudWalker

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Hello to everybody,
just came from a bad experience with mavic pro.

I've recalibrate the compass just before flight and after 2 seconds after take off the mavic has a compass error BUT still in P-GPS mode and became ungovernable and crash.

The question is WHY the mavic still in P-GPS mode with compass error and didn't switch to ATTI mode.

Any one has the same experience ?
I've not had this experience but have looked at several incidents where this has happened. The P3 does what you'd want; at the slightest hint of a compass error it switches to ATTI. The Mavic will often try to fix a compass error by remaining in GPS+ATTI and rotating the AC until magYaw (heading determined by the magnetometers) matches the Yaw value. It seems to work OK when the error is small enough.

If you want to know more about your incident you can retrieve the .DAT, Dropbox it, and post a link.
 

BudWalker

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I'm not an expert, but from what I can tell it's likely a "bad" calibration that was in range of ferrous material or an E.M. field. As soon as it left the area of influence, compasses were no longer "calibrated".

From your location, it could have been something under the road like cables or piping/conduit or reinforcing material.

Compasses govern heading, GPS governs position. The drone cannot infer heading from GPS, only direction of travel. Barring any serious malfunction, GPS mode will not be lost as long as satellite lock remains.

(This is also why calibration should be done in a known "safe" space, and not performed in the field before every flight - you raise the chance exponentially of interference causing a "bad" calibration).
A compass calibration can not detect and then compensate for magnetic effects external to the AC. It's mathematically impossible. It's a misconception that a calibration can be valid for one part of the flight but invalid for another part of the flight..

The possibility of obtaining a bad calibration is way, way overstated. Attempting to calibrate in a "bad" location will cause the calibration to be rejected with a "interference, move to a better spot" message.
 

CCDD

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I’ve said it before and I’ll say it again, most crashes are the fault of its owner and not the product. Too many just purchase, unbox and fly without taking the time to understand what they have, This forum is “overstocked” with helpful information, please take the time to read before blaming it on DJI.
 

kneeL

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I have these issues all the time and never lost control of my Mavic. When you get compass calibration and GPS issues that cannot be resolved by moving locations, you need to simply fly the drone back to safety. The crash was totally unrelated and likely due to the pilot panicking.

Also if you had one crash that you thought was a technical/mechanical error, you should have contacted DJI and sorted it out before attempting to "fix and fly again".
 

villasoftware

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People really need to stop propagating this false idea that you have to constantly calibrate the compass before every days flying.
It’s simply not necessary EVER unless the app tells you.
The risk of a bad cal is not worth it
Still complain compass error, and the calibration didn't solve this trouble !!!!!!!!

And if is not necessary to recalibrate why is explained on the mavic user manual ????????

The true is this is a engineering fails of mavic. So many people lost contro of his mavic due the compass, The mavic has 2 sensors why this happen if is so unnecessary ????

Best regards
 

kneeL

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The manual just tells you to do it, as its good to do it once right out of the box. However it is not necessary and I flew without calibrating.

I get the errors whenever there is too much metal or electronics nearby, you might be in a bad location...

You have tried in other locations far away from where this issue occurred?


Sounds to me like you calibrated it in a place with magnetic interference. This would explain your issues.

if you instead did not calibrate it, and moved to a different location alltogether, it likely would have been fine.

Last possibility is your sensor is bad and needs DJI to replace the hardware.

I have not heard many problems with this. Actually Mavic is one of the best flying machines out there on the market today
 

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They have the mavic gps\compass for sale brand new on Ebay..! Famous problem\issue with the Mavic i guarantee it..! Its drifting and spinning cause Gps\Compass is one module located in the rear...
 

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GPS/Compass... GPS = Tells drone where its on the map, where is home, find my drone, for keeping drone in one place... Compass = Tells drone which way its pointing so pilot can fly back & drone can fly in right direction... People are saying improper calibration but think about it doesn't the Mavic have super strong magnets in its 4 motors that's closer than the Mavic would be next to that would affect flight..? As far as GPS signal i find that highly unlikely that all satellites failed in the sky to çäüsë drone to drift... That's why some people can't find there drone cause last coordinates is not what drone transmitted when it failed mid flight... I can honestly say there's issues with the gps/compass modules in the Mavic/spark drones... Every flight is like a hit/miss... I'm worried that my drone might not come back home cause it doesn't know where home is...
 
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I've not had this experience but have looked at several incidents where this has happened. The P3 does what you'd want; at the slightest hint of a compass error it switches to ATTI. The Mavic will often try to fix a compass error by remaining in GPS+ATTI and rotating the AC until magYaw (heading determined by the magnetometers) matches the Yaw value. It seems to work OK when the error is small enough.

If you want to know more about your incident you can retrieve the .DAT, Dropbox it, and post a link.
Hi, I'm hoping to pick your informed brain for a minute or two: I just took a new Mavic Pro for a flight, first flight out of the box went well, tested the RTH function from 200 ft away, worked properly. Second flight I went higher and further, approx. 400 ft away and all went well. On return to my location the bird gave error message of compass failure followed by GPS failure. When off the sticks it should "park" in the sky and wait. Not this time, the Mav kept slewing sideways at a high rate of speed. All of this to ask if you'd be willing to look at the .DAT file. Where do I find it? On the microSD in the bird or does it have to be pulled using Assistant?
 

Tropdiver

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GPS/Compass... GPS = Tells drone where its on the map, where is home, find my drone, for keeping drone in one place... Compass = Tells drone which way its pointing so pilot can fly back & drone can fly in right direction... People are saying improper calibration but think about it doesn't the Mavic have super strong magnets in its 4 motors that's closer than the Mavic would be next to that would affect flight..? As far as GPS signal i find that highly unlikely that all satellites failed in the sky to çäüsë drone to drift... That's why some people can't find there drone cause last coordinates is not what drone transmitted when it failed mid flight... I can honestly say there's issues with the gps/compass modules in the Mavic/spark drones... Every flight is like a hit/miss... I'm worried that my drone might not come back home cause it doesn't know where home is...
Hey Spy808. I just got a MavPro and the second flight it did similar to what you described above. It had simultaneous failure of compass and GPS with red warnings on the screen and all. Bird was VERY hard to bring to land and if you let off the sticks it would just slew off in some random direction. My previous MavPros were rock solid. I haven't talked to DJI yet. I'm sure they'll just say "Send it in". Seems to be the standard answer. Is anyone else seeing this issue?
 

BudWalker

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Hi, I'm hoping to pick your informed brain for a minute or two: I just took a new Mavic Pro for a flight, first flight out of the box went well, tested the RTH function from 200 ft away, worked properly. Second flight I went higher and further, approx. 400 ft away and all went well. On return to my location the bird gave error message of compass failure followed by GPS failure. When off the sticks it should "park" in the sky and wait. Not this time, the Mav kept slewing sideways at a high rate of speed. All of this to ask if you'd be willing to look at the .DAT file. Where do I find it? On the microSD in the bird or does it have to be pulled using Assistant?
Sure. Look here to see how to retrieve the .DAT. from the Mavic. If you can't get that .DAT then try to get the .DAT off the tablet by looking here. You'll need to Dropbox it and post a link.
 

Tropdiver

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I don't have a Dropbox account, is there a chance I could email it to you?
I looked at the Dat file in CsvView, nice job building that. It's really easy to get a handle on what's happening when it's graphed. Can I assume a gpshealth of 5 is good and a zero is bad? Couple times during the flight it went to zero.
 

BudWalker

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I don't have a Dropbox account, is there a chance I could email it to you?
I looked at the Dat file in CsvView, nice job building that. It's really easy to get a handle on what's happening when it's graphed. Can I assume a gpshealth of 5 is good and a zero is bad? Couple times during the flight it went to zero.
You can try emailing it to [email protected]. But, my experience is that anything over 5 MB will cause email to choke.

Yes, gpsHealth < 4 is a problem. gpsHealth isn't necessarily linked to a low number of satellites. The FC computes lat/long coords based on GPS and IMU data. gpsHealth indicates the confidence in those computed coords. gpsHealth == 0 is usually an indicator that the FC isn't confident for reasons other than a low numSats.
 

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