Every flight within 5minutes I receive
MODE CHANGED TO ATTI  (NO GPS)

I have the latest firmware (yesterday installed) hope for help but no change.
I switched from Samsung S7 Edge to Huawei P9

The issue is within drone itself.
It reports strong magnetic interference and sudden lost GPS causing ATTI mode switch..

I am very concerned of crash and due to this failure I am affraid to fly ..

Please any help appretiated.
I found few threads with same issue but no resolution ..

It looks like you've uploaded at least one of your flight logs to AirData (HealthyDrones), but can you also upload it to PhantomHelp and provide a link to it in this thread?

I am very concerned of crash and due to this failure I am affraid to fly ..

I think you're right to be concerned and that you've made a good decision not to fly any more until the source of the problem is identified.

You should upload full log, you lost gps and had magnetic interference, the full log will show more. If you were flying in the same area and it was same notifications , then you should try another area.

Go take a walk over there and make sure there isn't a cell tower or a HAM radio operator or something.

GPS signals are weak and easy to jam.

DroneFlying Posted at 2017-5-12 06:40
It looks like you've uploaded at least one of your flight logs to AirData (HealthyDrones), but can you also upload it to PhantomHelp and provide a link to it in this thread?

I am very concerned of crash and due to this failure I am affraid to fly ..

Thank you

the link is:
http://www.phantomhelp.com/LogViewer/VC6BR6EWQOZ1QVYNBLNF/

it provides interesting information thank u
I did not know the phantomhelp page until now.

Do you have  idea what YAW ERROR is?
http://www.phantomhelp.com/LogViewer/VC6BR6EWQOZ1QVYNBLNF/

The thread title is misleading; you never lost satellites.  This is a compass error.

The Mavic uses GPS for positioning and compass for (rotation - "yaw") orientation.  So what happened is that the Mavic had a compass error and throughout that time the craft didn't know how it was pointing.  This is obviously a problem, because even if you know where you are, it's impossible to return home if you don't know how you are pointed.  The drone drops out of GPS mode because that situation can essentially cause a fly away when it ties to fly in a (wrong) direction and that makes it further away from where it wants to be so it flys more in the wrong direction... etc.

The compass may be failing, or there was legitimate magnetic interference.  I've had some mid-flight dropouts myself, and just like in your case it recovers quickly... 30 seconds or so.  I am personally convinced that this happens (at least sometimes) due to some overheating, but that's really just wild conjecture.  Either way, you handled it nicely, kept a cool head, and continued flying.

I'm not suggesting a compass calibration since as far as I can tell that causes more trouble than good most of the time.  For me, I'd keep flying, but everyone is different.  If you keep flying, just stay in control, fly VLOS, and keep a steady hand.  If the compass craps out again, you're faced with opening a ticket and all of that.  I'm hoping for sake it was a "one time" (or not very often time) glitch.

seeker_ktf_ Posted at 2017-5-13 04:22
The thread title is misleading; you never lost satellites.  This is a compass error.

The Mavic uses GPS for positioning and compass for (rotation - "yaw") orientation.  So what happened is that the Mavic had a compass error and throughout that time the craft didn't know how it was pointing.  This is obviously a problem, because even if you know where you are, it's impossible to return home if you don't know how you are pointed.  The drone drops out of GPS mode because that situation can essentially cause a fly away when it ties to fly in a (wrong) direction and that makes it further away from where it wants to be so it flys more in the wrong direction... etc.

Hi,
Thank you.
Correct it is not GPS Issue, but it looks as GPS Issue. Controller is reporting it this way.
Icon with number of Sattelites disappears and controller reports switch do ATTI mode due to GPS..

Phantomhelp site helped a lot it shows the correct Error which is compass.

healthy drones reported issue with GPS..

Now I know the issue is not GPS but Compass.

I will try multiple callibration of compass and will do test flight

and further help appretiated

Stejnaci Posted at 2017-5-13 06:53
Hi,
Thank you.
Correct it is not GPS Issue, but it looks as GPS Issue. Controller is reporting it this way.

Use this as a guide when calibrating compass,

Many things can distort the earth’s magnetic field in the area you are flying:

Steel framed or reinforced concrete buildings, bridges and roadways, iron pipes and culverts, high power electric lines, heavy equipment, trucks and automobiles, steel tanks, electric motors and even computers.
Flying between steel framed or reinforced high rise buildings will distort the magnetic field in addition to causing GPS multi-pathing.
Safe distances for compass calibration

6” (15 cm) minimum: Metal rim glasses, pen/pencil, metal watch band, pocket knife, metal zipper/buttons, belt buckle, batteries, binoculars, cell phone, keys, camera, camcorder, survey nails, metal tape measure.
18” (50 cm) minimum: Clipboard, data collector, computer, GPS antenna, 2-way radio, hand gun, hatchet, cell phone case with magnetic closure.
6 ft (2 m) minimum: Bicycle, fire hydrant, road signs, sewer cap or drain, steel pole, ATV, guy wire, magnets, chain-link fence, bar-wire fence, data collectors

that use a magnet to hold the stylus.
15 ft (5 m) minimum: Electrical box, small car/truck, powerline, building with concrete & steel.
30 ft (10 m) minimum: Large truck, metal building, heavy machin

You weren't going very fast. Weird happened over a lake too. I was expecting to see 25+mph.

I have a thread that details how I fixed my compass issues. But you have to be willing to give up warranty, and I know a lot don't want to do that. But it turns the mavic into what it was supposed to be. http://forum.dji.com/forum.php?mod=viewthread&tid=94664

I couldn't do half the things I do now. Temperature may have something to do with it (noticed compass issues when ambient was high compared to over the winter), but it's mainly emf off that rear motor wiring, the temperature is accelerating an already bad situation imo.

thehippoz Posted at 2017-5-13 08:53
You weren't going very fast. Weird happened over a lake too. I was expecting to see 25+mph.

I have a thread that details how I fixed my compass issues. But you have to be willing to give up warranty, and I know a lot don't want to do that. But it turns the mavic into what it was supposed to be. http://forum.dji.com/forum.php?mod=viewthread&tid=94664

thank U all
all responses were very usefull

today I calibrated IMU and Compass, but now there is a storm and heavy rain outside so I plan do perform test soon,

DJI Support responsed with this advice:
Please calibrate the IMU firstly and then calibrate the compass. Fly the drone in an open filed places without interference. ( any high voltage power can cause interference)
Please also do the gimbal calibration. If the firmware of the drone is not the latest, it is advised to use the latest one.


I also like advice of checking sensor.
My plan is to calibrate, and let mavic fly in safe distance and wait if the issue occurs.
I will monitor Compass sensor from menu (Compass 1 and Compass2)

hope it will help
if not I will need to use warranty support

I just wanted to say that I'm currently having a similar issue with our Phantom 4 Pro.  I'll have 15-17 satellites on the ground and after anywhere from 30 seconds to 2 minutes, I'll loose all GPS assistance.  According to my logs, I get this error "In Flight,workingGPSencountersdata exception" and "GPS Position NoMatch".  No matter where I fly in the county or how many times I calibrate compass/IMU, the problem remains.  Here's the LOG from my last flight:
http://www.phantomhelp.com/LogViewer/MFUIJ824HRO8IYNU3NBM/