With a full bar of gps satellites on the remote, suddenly the Mavic started drifting and went more than 2 miles away from me. I am a very prudent flyer and never let the Mavic go out of my sight. I already recalibrated the compass but the problem is still there. Today in the middle of a field, he reports a satellite positioning is off problem and starts to drift. The little red arrow started to point to all directions.
A Phantom nearby had no problem so the problem must be with Mavic. I synchronised all filghts to DJI and Healthtydrones so I ask the forum to take a look before I send the aircraft in.

Sounds like you were fortunate enough to get GPS back. What you included is just a screen shot; how about sharing the actual log via a link to HealthyDrones? Anyway, if this is the classic "spontaneous GPS loss" problem, I doubt that sending your drone in will result in a fix.

This the flight
http://healthydrones.com/main?share=QxUMeT
The strange thing is that the gps count remained high throughout.

fans3e53881d Posted at 2017-2-15 13:01
This the flight
http://healthydrones.com/main?share=QxUMeT
The strange thing is that the gps count remained high throughout.

Number of satellites in sight (GPS number) can be high but the positioning accuracy can be poor at the same time. This depends of many factors.
I think Mavic could switch to Atti if GPS accuracy becomes low (even if GPS number still high).

As always, it would be great to hear DJI engineers here. But these kind of issue was never clarified by them.

What the weather it was: clear sky, clouds, snowing?

Also as it from your logs - your RC connection was good all the time. Why didn't you fly back visually by phone screen?

Well I was flying with my Phantom3P together with my brother and his Mavic. My satellite count was high and the positioning was rocksteady.
The weather was wonderful, no wind, lightly cloudy. By far the best way to test is flying with two drones.

My brother was panicking and was completely clueless

The issue you experienced is characterized by the GPS health dropping below 4 where it drops into Atti and the AC can drift with the wind if not properly controlled. When the Gps health drops (the 5 bars next to the umber of satellites), the GPS number will usually stay high. There are numerous reports of this on both this forum and mavicpilots.com. In same cases once the AC dropped into ATTI, the AC was reported to be uncontrollable.

Hopefully the folks at DJI are working on this problem. There have been several reports of  crashing when this occurs. In your case you were lucky because you were at a high altitude, and the GPS health came back. When this occurred, you still had enough gps signal for navigation, but not enough for flight control.   It may have been interference or it could be a week GPS module.

Sergey_B.
My brother was panicking and was completely clueless as to where his Mavic was. He flies always with the aircraft closeby and is not used to navigate based on the screen. Trying to identify what you see on the screen is what my brother bewildered, instead simply bringing the red arrow back regardless where it's flying.
But after several unsucessfull RTH attemps, the Mavic finally limped back though not in a straight line. I think the GPS and compass were fighting each other.

I really hope DJI can step forward and explain this GPS problem. Its their damn responsibility to the customers. We can't live with this . I have  GPS in my boat and my car, and they never fail.
I´ll bet they blame the satellites .

The log shows a Class D Warning Zone message. It does say "fly with caution" implying you are still good to go, but wonder if there is some underlying conflict in the software. I believe restricted zones won't let you fly, maybe there's a glitch with warning zone activities. Just a thought.

fans3e53881d Posted at 2017-2-15 13:01
This the flight
http://healthydrones.com/main?share=QxUMeT
The strange thing is that the gps count remained high throughout.

Sorry....off topic....is there a FAQ or tutorial on how to do this?  Get flight data from the Mavic or Go 4 app (IOS) and upload to HD?

ontwowheels Posted at 2017-2-16 07:52
Sorry....off topic....is there a FAQ or tutorial on how to do this?  Get flight data from the Mavic or Go 4 app (IOS) and upload to HD?

The instructions are near the top of this Healthy Drones page.

Teesquar Posted at 2017-2-16 07:15
The log shows a Class D Warning Zone message. It does say "fly with caution" implying you are still good to go, but wonder if there is some underlying conflict in the software. I believe restricted zones won't let you fly, maybe there's a glitch with warning zone activities. Just a thought.

You can fly in a restricted zone. I live in a Class C warning zone. No problems flying there. Only a warning at starting up the Magic.

DroneFlying Posted at 2017-2-16 07:53
The instructions are near the top of this Healthy Drones page.

Well hell......THANKS ;-)

ontwowheels Posted at 2017-2-16 07:58
Well hell......THANKS ;-)

No problem. I should have also mentioned that if you're using DJI Go 4, the easiest way is to download and use Healthy Drones' HD Sync app. Otherwise, you're forced to transfer the logs manually, which is a minor hassle.

Teesquar Posted at 2017-2-16 07:15
The log shows a Class D Warning Zone message. It does say "fly with caution" implying you are still good to go, but wonder if there is some underlying conflict in the software. I believe restricted zones won't let you fly, maybe there's a glitch with warning zone activities. Just a thought.

That's a possibility as I have had this problem twice now and both times I was in a warning zone.
It was at 400ft and about 1000 yards away on the last occasion but managed to get it home in ATTI mode.
I was lucky that I had about 80% battery charge left as it was a struggle and just as I got it back to my location it returned to GPS mode.
Previous time it was low and just overhead and nearly hit a telegraph pole but managed to bring it down in a nearby feild

It is not only a green warning zone, but inside is also a yellow authorisation zone. So we do an advanced authorisation before flying there. But the problem also occurred away from these special zones in Sint-Truiden.

Glad you got it back, are you on the latest firmware?
And you said it started drifting and it went 2 miles away are a prudent flyer and never let the Mavic out of your sight. Are you saying that you could see the Mavic from 2 miles away?

Also, do not rely on anything Healthy Drones data states as they cannot correctly decode the data from the aircraft.If you upload your flight record and provide the Dropbox link I wil forward to R&D for them to review.

ontwowheels Posted at 2017-2-16 07:52
Sorry....off topic....is there a FAQ or tutorial on how to do this?  Get flight data from the Mavic or Go 4 app (IOS) and upload to HD?

Please do not rely on Healthy Drones as they do not have the capability to correctly decode the flight data.

DJI-Ken Posted at 2017-2-16 08:39
Glad you got it back, are you on the latest firmware?
And you said it started drifting and it went 2 miles away are a prudent flyer and never let the Mavic out of your sight. Are you saying that you could see the Mavic from 2 miles away?

It was windy and while struggling it drifted away with the wind. As soon as I lost sight I also got disoriented and did not understand what I was seeing on the screen. I don't know how many time sI pushed RTH, as I stated before, in the end it came back towards me. I was 100 % the Mavic was gone.
I don't rely on Healthydrones and I synced all the all the flights to DJI under the account of etienne.wintmolders@gmail.com. I also started a problem report with your support service and they replied promptly. I am very much interested in the many opinions in this forum to have a wider look on the problem. And also the help of the DJI-people who participate.

Etienne_W Posted at 2017-2-16 10:59
It was windy and while struggling it drifted away with the wind. As soon as I lost sight I also got disoriented and did not understand what I was seeing on the screen. I don't know how many time sI pushed RTH, as I stated before, in the end it came back towards me. I was 100 % the Mavic was gone.
I don't rely on Healthydrones and I synced all the all the flights to DJI under the account of . I also started a problem report with your support service and they replied promptly. I am very much interested in the many opinions in this forum to have a wider look on the problem. And also the help of the DJI-people who participate.

I'm looking at your last flight and I do see a few times your satellite signal went down to 1 bar and it went Red. But it only went out for a split second then came back. And your altitude 23ft so it went into P-Opti and not ATTI mode since you were withing VPS range. So if it drifted then I would think it was very heavy wind BUT I see your attitude is almost level so it wasn't fighting the wind.
I also see you took off with no GPS and it didn't lock into GPS mode until 1:35 minutes into the flight.
I see plenty of satellites but a weak signal when it went into OPTI mode.

I'd suggest flying in a different area several miles away and if you get the same results then restore the factory settings and also refresh the firmware as it couldn't hurt. And you are on the latest firmware correct?
If all this doesn't resolve it and you have nothing mounted on the Mavic (blocking the GPS) then I think you may want to contact support and sent it in for evaluation.
Also, the only real long distance flight I see where you said you lost it and it came home I see the same issue as it went into ATTI mode since your altitude was outside of VPS range. But I see you took control after it went into ATTI mode. I see that happening a few times and only once you put it into RTH but only for 10 seconds then you flew it home in GPS mode.

Thanks a lot for this detailed reconstruction. I will follow your advise, restore to factory settings and make sure the latest firmware is used and fly in another place.
But I must tell you that from the first day I started flying I was surprised that the craft switched so many time sin and out of GPS mode, but I paid no attention because it flew like a dream, silently and smooth.
I became used to this switching until I flew on a slightly windy day on flight that supposed to be short distance, but became a unintentioned long distance flight. Your reconstruction is based on the log, mine on a frightened pilots memory. Maybe I pushed many times on RTH, enabled it, disabled it. IN the end I didn't know if continuing made any sense. Until it came home.
Let's talk about the last flight. Used to the on and off switching I launch the Mavic and hope it finds the satellites, and when it looses them  I stay put until they come back. A few posts back I uploaded a picture of the field were we were flying. Those are fruittrees of 3 m high, could it be that the VPS went nuts because of the constant variation of height. Anyway it was in a field far away from buildings and I flew together with a Phantom and the difference was clear. We'll do another test and let you know how it went. Thanks.

DroneFlying Posted at 2017-2-16 08:03
No problem. I should have also mentioned that if you're using DJI Go 4, the easiest way is to download and use Healthy Drones' HD Sync app. Otherwise, you're forced to transfer the logs manually, which is a minor hassle.

Thanks....I did a few manually just to check it out.  If I upload more I'll take a look at their app.

DJI-Ken Posted at 2017-2-16 08:42
Please do not rely on Healthy Drones as they do not have the capability to correctly decode the flight data.

Yes sir.  If I do have an issue with the Mavic I will reach out to support.  Knock on wood all has been fine so far, 17 flights.  Will be flying more this weekend.

ontwowheels Posted at 2017-2-17 06:42
Yes sir.  If I do have an issue with the Mavic I will reach out to support.  Knock on wood all has been fine so far, 17 flights.  Will be flying more this weekend.

No problem, we're here to assist with any questions you may have. Enjoy your weekend flying.