I updated my Mavic Pro to 0200.
I went to a park where is very flat without any high building/trees yesterday.
I flew there tens of times without any issue.
But yesterday Mavic Pro lost GPS and flew away hundres of meters - I was thinking I will lost it as I can't see the distance/RTH stopped working.
Finally I found out the vision is still working, so I turned it around and found my direction and flew it back.
It almost gave me a heart attack.

Why Mavic Pro will lost GPS when there are 14-15 satellites?



https://www.skypixel.com/videos/569be586-9fa9-4f9a-a546-5b80f066d579?utm_source=url&utm_medium=copied&utm_campaign=share

Hi there, please try to refresh the firmware, calibrate the compass and change another location to fly. If the issue happens in many places, you might need to send the drone in. Please contact our support for a further help. Here’s the link to contact us: http://www.dji.com/support

DJI Thor Posted at 2018-2-24 02:55
Hi there, please try to refresh the firmware, calibrate the compass and change another location to fly. If the issue happens in many places, you might need to send the drone in. Please contact our support for a further help. Here’s the link to contact us: http://www.dji.com/support

Thanks!
It happened twice in 170 flights.
So I didn't decide to turn it in yet.
If too many, will do.

your flying around a prison, is that legal in Australia.  and you are getting yaw and compass errors continuously . You may have sats. but you lost your compass bearings. also even though it shows 15 sats, there are only 2 bars, showing a weak signal. And you were in ATTI mode.

You did not lose the satellites, your AC decided to switch to ATTI because of the compass error.

Locoman Posted at 2018-2-24 03:06
your flying around a prison, is that legal in Australia.  and you are getting yaw and compass errors continuously . You may have sats. but you lost your compass bearings. also even though it shows 15 sats, there are only 2 bars, showing a weak signal. And you were in ATTI mode.

I am not aware there is a prison? I checked the map. It is legal to fly there, just away from people.

I'm curious as to why you didn't upgrade to v01.04.0300 instead of the .0200 one.

It looks as though its compass interference, where there is conflict between the normally accurate compass heading and the GPS data, causing it to switch to ATTI mode.

Difficult to tell, but it may have been triggered by your flight over the prison.  Perhaps they have deterrents in place.

Aardvark Posted at 2018-2-24 03:55
I'm curious as to why you didn't upgrade to v01.04.0300 instead of the .0200 one.

It looks as though its compass interference, where there is conflict between the normally accurate compass heading and the GPS data, causing it to switch to ATTI mode.

I was with 0300 but I got DJI GO app no response 3 times - that's very scary, so I downgraded to 0100, but always got gimbal reset in the air, then tried 0200, then got the compass error, now back to 0300 again.
No one is working without defect

Why you guys say there is a prison? It is a park. No prison.
I read the map, may be it is prison? I don't know, doubled wall?

But campass error happened far away from that prison, it drifted to the place (prison?) after a long distance in the air.

Wachtberger Posted at 2018-2-24 03:23
You did not lose the satellites, your AC decided to switch to ATTI because of the compass error.

The question is:
The drone took off without error, it is in 24m high in the air and 9m/s speed, anything can interfere a drone compass at that height and speed? How strong can that be?
I remember I flew there before, it didn't happen with 0100 version.
I can try again with the same path - if it happens again, maybe it is the place.
If it doesn't happen, maybe it is the drone - maybe 0200 firmware.

flybirdpro Posted at 2018-2-24 03:59
I was with 0300 but I got DJI GO app no response 3 times - that's very scary, so I downgraded to 0100, but always got gimbal reset in the air, then tried 0200, then got the compass error, now back to 0300 again.
No one is working without defect

"Why you guys say there is a prison? It is a park. No prison.
I read the map, may be it is prison? I don't know, doubled wall? "

The double wall might be a good hint as you say.

Must be a nice place though, it got a 3.6/5 rating

flybirdpro Posted at 2018-2-24 04:06
The question is:
The drone took off without error, it is in 24m high in the air and 9m/s speed, anything can interfere a drone compass at that height and speed? How strong can that be?
I remember I flew there before, it didn't happen with 0100 version.

Yes, there are many "maybes", testing (also in other unbuilt areas for comparison) will be the best way to find out. If the compound that is visible on your picture above is really a prison, it can well be that they have installed a drone jammer. All kind of "deliveries" by drones to prisons have become quite popular. In my country it is strictly prohibited to fly anywhere near a prison (as well as certain other facilities).

flybirdpro Posted at 2018-2-24 04:06
The question is:
The drone took off without error, it is in 24m high in the air and 9m/s speed, anything can interfere a drone compass at that height and speed? How strong can that be?
I remember I flew there before, it didn't happen with 0100 version.

What can sometimes happen is that the compass may have been last calibrated not very well. Perhaps over reinforced concrete, or too close to some metal structure. When the aircraft is away from the bad calibration point this can cause it to start generating errors.

Aardvark Posted at 2018-2-24 04:19
"Why you guys say there is a prison? It is a park. No prison.
I read the map, may be it is prison? I don't know, doubled wall? "

Can't believe there is a prison near a park!
What a waste of the beautiful place! And dangerous if someone break out.

Wachtberger Posted at 2018-2-24 04:21
Yes, there are many "maybes", testing (also in other unbuilt areas for comparison) will be the best way to find out. If the compound that is visible on your picture above is really a prison, it can well be that they have installed a drone jammer. All kind of "deliveries" by drones to prisons have become quite popular. In my country it is strictly prohibited to fly anywhere near a prison (as well as certain other facilities).

I checked the date, the 1st time also happened with version 0200.
So I guess 0200 is not stable with compass - it never happened with 0100 or 0300.
In fact, 0200 is so short life (10 days only then 0300 was released), I didn't fly much with it.

flybirdpro Posted at 2018-2-24 05:05
I checked the date, the 1st time also happened with version 0200.
So I guess 0200 is not stable with compass - it never happened with 0100 or 0300.
In fact, 0200 is so short life (10 days only then 0300 was released), I didn't fly much with it.

I trust that there are always good reasons why DJI releases firmware updates. Thus I would always install the latest version immediately. This can be also relevant for warranty. In your case it can well be that there was an issue with 0200.

It would seem the compass is the crux of the problem - the cascade of settings after that initial yaw error then followed. I had the same happen - a yaw error then down into ATTI and initially no stick control as the RC and MPP renegotiated the control mode. I suspect (but not yet personally verified!) there is a 'gimbal lock' situation going on with the compass - where a sudden/fast yaw can offset the compass, which then causes and inconsistency with the GPS inputs, so the control software drops into the next best control setting. It is possible that the orientation when the drone first sets Home point can have an effect - I try to always orientate/take off in a east or west pointing direction - assuming that the 'zero' point for the compasses is magnetic north. I've seen on some people's flight records that show compass readings the compass values jumping from near zero to 180 ... basically a compass flip-over. This could either be a physical 'compass needle' phenomenon or the way the algorithm is written to analyse the compass outputs. (As I doubt the programmers are using quaternions for the calculations).

After I did the .DAT data analysis, I confirmed 0200 had a fatal defect - it showed GPS mode and you took off but in fact there was 0 satellite in use, so it turned to ATTI mode in the air - if you were not lucky you lost your mavic as ATTI could not stay still in the air, it just flew away from you.
It happened to me twice. So please don't use 0200 as it only had 10 days life and was replaced by 0300.

1. took off as GPS mode with 13 satellites

2. after a few seconds turned to ATTI mode when still saw 14 staellites

3. check .DAT and saw GPS number = 0 and GPS level = 0 even we saw there were 13-15 satellites in the screen capture

4. Compass status abnormal

flybirdpro Posted at 2018-2-27 11:42
After I did the .DAT data analysis, I confirmed 0200 had a fatal defect - it showed GPS mode and you took off but in fact there was 0 satellite in use, so it turned to ATTI mode in the air - if you were not lucky you lost your mavic as ATTI could not stay still in the air, it just flew away from you.
It happened to me twice. So please don't use 0200 as it only had 10 days life and was replaced by 0300.

Which software did you use for analysing the .DAT file?

DJI Thor Posted at 2018-2-24 02:55
Hi there, please try to refresh the firmware, calibrate the compass and change another location to fly. If the issue happens in many places, you might need to send the drone in. Please contact our support for a further help. Here’s the link to contact us: http://www.dji.com/support

Is there anything that is causing this to occur on any other Mavic Pro?

Lamplighter55 Posted at 2018-2-24 05:39
It would seem the compass is the crux of the problem - the cascade of settings after that initial yaw error then followed. I had the same happen - a yaw error then down into ATTI and initially no stick control as the RC and MPP renegotiated the control mode. I suspect (but not yet personally verified!) there is a 'gimbal lock' situation going on with the compass - where a sudden/fast yaw can offset the compass, which then causes and inconsistency with the GPS inputs, so the control software drops into the next best control setting. It is possible that the orientation when the drone first sets Home point can have an effect - I try to always orientate/take off in a east or west pointing direction - assuming that the 'zero' point for the compasses is magnetic north. I've seen on some people's flight records that show compass readings the compass values jumping from near zero to 180 ... basically a compass flip-over. This could either be a physical 'compass needle' phenomenon or the way the algorithm is written to analyse the compass outputs. (As I doubt the programmers are using quaternions for the calculations).

It could also be the area around you where the GPS coverage is located?

Lamplighter55 Posted at 2018-2-24 05:39
It would seem the compass is the crux of the problem - the cascade of settings after that initial yaw error then followed. I had the same happen - a yaw error then down into ATTI and initially no stick control as the RC and MPP renegotiated the control mode. I suspect (but not yet personally verified!) there is a 'gimbal lock' situation going on with the compass - where a sudden/fast yaw can offset the compass, which then causes and inconsistency with the GPS inputs, so the control software drops into the next best control setting. It is possible that the orientation when the drone first sets Home point can have an effect - I try to always orientate/take off in a east or west pointing direction - assuming that the 'zero' point for the compasses is magnetic north. I've seen on some people's flight records that show compass readings the compass values jumping from near zero to 180 ... basically a compass flip-over. This could either be a physical 'compass needle' phenomenon or the way the algorithm is written to analyse the compass outputs. (As I doubt the programmers are using quaternions for the calculations).

Agree that yaw error likely cause by compass error  If no compass errors were issued - the problem may be cause by a previous compass calibration in a distant location. In that case the  compasses would agree with each other but due to magnetic deviation, they're both point the wrong way by a few degrees,

Wachtberger Posted at 2018-2-27 12:20
Which software did you use for analysing the .DAT file?

C:\Program Files (x86)\DJI Product\DJI Assistant 2\Assistant\Viewer.exe
Or you have to connect your drone to PC to use this app. What a stupid design.
I told DJI bbs admin to pass this information to developers - allow users to pick the feature from menu without connect the drone, what a waste of time.

flybirdpro Posted at 2018-2-27 13:50
C:\Program Files (x86)\DJI Product\DJI Assistant 2\Assistant\Viewer.exe
Or you have to connect your drone to PC to use this app. What a stupid design.
I told DJI bbs admin to pass this information to developers - allow users to pick the feature from menu without connect the drone, what a waste of time.

Thank you very much for this! First time I read about it, unbelievable...

Wachtberger Posted at 2018-2-27 13:53
Thank you very much for this! First time I read about it, unbelievable...

You are welcome!
You know I was forced by DJI to learn all the tools to find out what happened. Can't get any real help from them. If they can help, it is not necessary for an owner to do all these works.
I talked so much with DJI BBS admin and only 2 options from DJI:
1. share your data - video size/frame set, firmware version, photo, video, screen capture, flight log, but they never tell you anything about your data, but tell you to turn in your drone, so share the data is just waste your time
2. turn in your done
So whatever you do, the ONLY way is to turn in your drone to DJI which will cost 4-6 weeks!

I asked DJI so many times about my gimbal reset in the air lead to video/photo can't work in about 30 seconds until reset is done (saw plenty of other owners have the same issue):
1. This problem happened so many times, what is the root cause?
2. If hardware failure, sure turn it in and replace the part and get it fixed
3. If firmware defect, the only way is to upgrade to a new firmware

But they don't know what is the root cause so I didn't turn in my drone but wait for a new version.

flybirdpro Posted at 2018-2-27 14:01
You are welcome!
You know I was forced by DJI to learn all the tools to find out what happened. Can't get any real help from them. If they can help, it is not necessary for an owner to do all these works.
I talked so much with DJI BBS admin and only 2 options from DJI:

I wish you good luck to get the problems solved! And I look forward to play with "Viewer", thank you again for that hint!

Wachtberger Posted at 2018-2-27 14:05
I wish you good luck to get the problems solved! And I look forward to play with "Viewer", thank you again for that hint!

Have a look Here probably everything you would want to know regarding the .dat file viewer in Assistant 2.

Aardvark Posted at 2018-2-27 15:00
Have a look Here probably everything you would want to know regarding the .dat file viewer in Assistant 2.

That is fantastic, thank you very much indeed!

Wachtberger Posted at 2018-2-27 15:03
That is fantastic, thank you very much indeed!

Part 2
Part 3
Part 4
Part 5
Part 6

and finally

Part 7

Once you've digested it all you can tell me how it works

davidmartingraf Posted at 2018-2-27 12:51
It could also be the area around you where the GPS coverage is located?

In my case - unlikely, as its an open space higher than the surrounding buildings and trees etc. But I guess heavy interference from other radio signals including WiFi, TV etc. could be a contributory factor.

Lamplighter55 Posted at 2018-2-27 16:00
In my case - unlikely, as its an open space higher than the surrounding buildings and trees etc. But I guess heavy interference from other radio signals including WiFi, TV etc. could be a contributory factor.

Does your phone pick up GPS accurately in your area that you're flying?

flybirdpro Posted at 2018-2-27 14:01
You are welcome!
You know I was forced by DJI to learn all the tools to find out what happened. Can't get any real help from them. If they can help, it is not necessary for an owner to do all these works.
I talked so much with DJI BBS admin and only 2 options from DJI:

I agree with you

davidmartingraf Posted at 2018-2-27 16:11
Does your phone pick up GPS accurately in your area that you're flying?

Indeed it does.

Lamplighter55 Posted at 2018-2-28 09:18
Indeed it does.

Yeah if your phone has no problems with GPS then your drone technically should have no problems, either.

davidmartingraf Posted at 2018-2-28 14:01
Yeah if your phone has no problems with GPS then your drone technically should have no problems, either.

Not necessary as it is the DJI firmware controlling the drone - anything wrong in the firmware will show different behavior than "in theory"

flybirdpro Posted at 2018-2-28 16:06
Not necessary as it is the DJI firmware controlling the drone - anything wrong in the firmware will show different behavior than "in theory"

There is a GPS module in the craft that has GPS and GLONASS like your phone so the core technology should be the same?

davidmartingraf Posted at 2018-2-28 17:24
There is a GPS module in the craft that has GPS and GLONASS like your phone so the core technology should be the same?

The hardware is the same, the software can be different.
We are humans, software always has defect, you can see I use "data" proved DJI Mavic 0200 has fatal defect.

flybirdpro Posted at 2018-2-28 17:32
The hardware is the same, the software can be different.
We are humans, software always has defect, you can see I use "data" proved DJI Mavic 0200 has fatal defect.

I wonder what DJI numbers look like for the defect rate of the Mavic Pro? I think because the Mavic Pro took several months to be shipped after it was announced likely contributed to the higher defect rate as compared to other DJI drones? I'm hoping the numbers are pretty consistent for all DJI drones, but suspect the Mavic may be a bit higher just from all the feedback?

davidmartingraf Posted at 2018-2-28 17:39
I wonder what DJI numbers look like for the defect rate of the Mavic Pro? I think because the Mavic Pro took several months to be shipped after it was announced likely contributed to the higher defect rate as compared to other DJI drones? I'm hoping the numbers are pretty consistent for all DJI drones, but suspect the Mavic may be a bit higher just from all the feedback?

1. DJI drones are new in the market
2. DJI developers are not perfect
3. DJI doesn't listen to customer's feedback
4. DJI fix is really slow - gimbal reset in the air is not fixed yet since Mavic pro was released
So play with it, update to latest firmware, enjoy it with the pain of the defects

flybirdpro Posted at 2018-2-28 19:04
1. DJI drones are new in the market
2. DJI developers are not perfect
3. DJI doesn't listen to customer's feedback

I think DJI takes customers' feedback like you said with a grain of salt, but feedback is better than no feedback.

davidmartingraf Posted at 2018-2-27 12:50
Is there anything that is causing this to occur on any other Mavic Pro?

This is a well known issue on drones (not only on DJI) , the Mavic is also affected.
In my experience the Phantom 3 is less affected.
Following the the firmware of evolution the MP since December 2016 the compass and the redundancy switch algorithm had been drastically improved.
At the I had in 2016 and early 2017 also some switchover to ATTI with the MP and found out that if both compasses are still continuously below 75 the switchover to ATTI does not occur; sometimes a redundancy compass switch.
That's why I check the compasses before every flight and make a good calibration if needed.
Note: The magnetic earth field is not always settled and that's also you have a Kp index in apps like UAVForecast