Sudden lost of GPS
624 4 2018-12-5
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Fred F
lvl.4
Flight distance : 4676457 ft
Australia
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After many months of flights in different countries, I now quite confident to say that the Mavic Pro(s) I have, and I have 4 all told, one was lost to the sea by wind, can lost GPS suddenly mid air, even in open space.

I had only ever crashed the drone twice, both time, it seem to indicate a lost of GPS mid air, unfortunately, both time they were near objects, and drifted very very fast to one side, both times.  Other times, I notice whilst mid air, it would suddenly drift very fast, citing lost of GPS, fortunately, the drone was in open space.  After a few moments, it would regain GPS.

Has anyone this expereince, and who can explain why GPS would be lost in open space.  I had expereinced this in Australia, as well as parts of mainland Europe and Iceland.
2018-12-5
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DeuceDriv3r
Second Officer
Flight distance : 4698533 ft
United States
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only time my mavic pro has dropped all sats instantly (tracking 19 or 20 at the time if I recall ) was because it went into atti mode.  reviewing the .dat file from the aircraft in csvview and airdata was that the loss of statilites was after a compass error(s) that piled up in less than a second and the drone went into atti mode, seemingly dropping all sats and either restarting the FC or resetting it.  control in atti as ok but delayed and I was able to keep the mavic on a homebound course and about a minute or so into the return flight position mode came back and it had full sats again.  I have seen videos on youtube showing the wires leading to the gps board in the 'tail' can crack at the solder joint due to poor application of white glue and once repaired fixed gps but that guy had no gps at all but I suspect if the wire is just starting to go it could start as an intermittent problem
2018-12-5
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Fred F
lvl.4
Flight distance : 4676457 ft
Australia
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DeuceDriv3r Posted at 12-5 06:19
only time my mavic pro has dropped all sats instantly (tracking 19 or 20 at the time if I recall ) was because it went into atti mode.  reviewing the .dat file from the aircraft in csvview and airdata was that the loss of statilites was after a compass error(s) that piled up in less than a second and the drone went into atti mode, seemingly dropping all sats and either restarting the FC or resetting it.  control in atti as ok but delayed and I was able to keep the mavic on a homebound course and about a minute or so into the return flight position mode came back and it had full sats again.  I have seen videos on youtube showing the wires leading to the gps board in the 'tail' can crack at the solder joint due to poor application of white glue and once repaired fixed gps but that guy had no gps at all but I suspect if the wire is just starting to go it could start as an intermittent problem

Thanks for the info on possibility of a dry joint etc., I need to keep an eye on which drone was exhibiting that particular problem, as I have three on hand. Then again, I know for sure, it happened on at least 3 different drones, as two were crashed and later replaced with one with a different s/n.

And why would in the mid air, compass error would show up, especially in the wilderness?  Perhaps strong magnetic interference from rocks, but so far up in the air, I am talking about 30 to 40 meters or even higher sometimes.
2018-12-5
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DeuceDriv3r
Second Officer
Flight distance : 4698533 ft
United States
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Fred F Posted at 12-5 12:29
Thanks for the info on possibility of a dry joint etc., I need to keep an eye on which drone was exhibiting that particular problem, as I have three on hand. Then again, I know for sure, it happened on at least 3 different drones, as two were crashed and later replaced with one with a different s/n.

And why would in the mid air, compass error would show up, especially in the wilderness?  Perhaps strong magnetic interference from rocks, but so far up in the air, I am talking about 30 to 40 meters or even higher sometimes.

there are multiple sensors that provide heading.. and its the FC and the firmware driving the FC to determine how to 'combine, filter, monitor' those sources and try to determine actual heading..

the algorithms used to determine that, combined with the information coming from the accelerometers, gyros, compasses, and gps are complex and when the FC can't figure out what to do, dji doesn't handle it very gracefully and it resets going into atti mode while it does..

now there can be legitimate hardware failures and interfennce and other external sources that can cause issues as well.. but at least in the cases of atti that I have had, the log data points to the FC firmware...
2018-12-5
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Yam Jemes
New

Norway
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Same happend to me dont know why but it just lost connection and i couldnt find it considering it was 3km away from me.
2018-12-13
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