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Sudden Weak GPS/ATTI - DJI-Ken /Mindy / Natalia
1196 27 2016-12-2
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Danny-B-
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Hi folks,

So I took my Mavic out at lunchtime for my second test flight .. I was testing a few things and ended up in sports mode just cruising about showing one of my collegues how it handles etc ...
Everything was working fine and I had 18 - 22 sats. I was orbiting a church just manual control and in sports mode still but was very smooth .. then flew back towards my take off area.

I flew over my head and takeoff point and a message popped up to say "weak GPS" then dropped to ATTI mode .. still said I had 22 sats but red for signal. I steered it back towards myself and within 10 seconds or so I had GPS lock again and still 22 sats. Its worth noting that I had full control, no controler disconnections etc, so no incidents like other have reported, but I was a little worried why it had dropped out of GPS lock but still had 22 sats?
I landed soon after that as I was a bit worried that it might do it again, but everything seemed fine. I then put a fresh battery in a while later and flew without any issues at all, for a good 15 mins or so flight (no sports mode though)

DJI-Ken/Mindy/Natalia etc, can you take a look at the logs to see if there is anything that points to the issue? is it error with the GPS/Compass device under certain conditions?

Flight log details are:
12:15:47 (today the 02/12/16)
Incident where atti mode switched was 7m:50s
I have syncronised the logs with the server

Any questions just let me know, i'm interested in finding out the cause of GPS loss, and if we can find a solution or condition to avoid.

2016-12-2
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canadianairborn
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bump bump bump
2016-12-2
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CamStevens
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Following.  I see other threads where other operators hypothesize this could be related to Sports mode.
2016-12-2
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Danny-B-
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CamStevens Posted at 2016-12-2 18:39
Following.  I see other threads where other operators hypothesize this could be related to Sports mo ...

Thats what i'm wondering, but it wasnt like i was going full speed at the time this happened. I had been travelling faster a few minutes before ...

I'm not interested in over reacting or blame storming, i just want to find the cause and find a resolution
2016-12-2
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Drmerlin
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I had something similar this morning. Suddenly dropped out of GPS mode and into Atti Mode. I was only a few hundred feet out and had something like 18 sats. I was in the process of bringing it back when GPS mode resumed... No further problems after that.... I had not used Sport Mode today. Had previously been flying in Tripod Mode without an issue...
2016-12-2
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Warrior200
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Something is messing with our satellites.
2016-12-2
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BrandonA614
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That's exactly what happened to me, but I wasn't able to recover.
IMG_0611.PNG
2016-12-2
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DJI-Ken
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BrandonA614 Posted at 2016-12-2 12:11
That's exactly what happened to me, but I wasn't able to recover.

I replied to your thread asking for your email address so I can review your flight.
2016-12-2
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DJI-Ken
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Danny,
What is your email and I can review your last flight.
Make sure your compass is calibrated correctly as it could cause a conflict to the flight controller if there's interference from a compass calibration.
2016-12-2
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Danny-B-
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DJI-Ken Posted at 2016-12-2 20:22
Danny,
What is your email and I can review your last flight.
Make sure your compass is calibrated co ...

Cheers Ken, pretty sure compass is spot on i calibrated it properly. Im sure it would have flew away if not when it switched to atti mode. Interfience meter shows green

My email address is dannyb81666@gmail.com

Cheers,
2016-12-2
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BrandonA614
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DJI-Ken Posted at 2016-12-2 15:21
I replied to your thread asking for your email address so I can review your flight.

Sorry Ken. Didn't see it. bavery614@gmail.com
2016-12-2
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MavicNewbie
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Well, I got a similar problem but unfortunately that was during landing. The Mavic was totally lost control and crashed.
Hey @DJI-Ken, would you mind if have a quick look of my flight log as well?
2016-12-2
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DJI-Ken
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MavicNewbie Posted at 2016-12-2 14:27
Well, I got a similar problem but unfortunately that was during landing. The Mavic was totally lost  ...

Sync your flight records and star the flight as a favorite.
What is your email ?
2016-12-2
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DJI-Ken
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BrandonA614 Posted at 2016-12-2 14:24
Sorry Ken. Didn't see it. bavery614@gmail.com

I responded in the thread you made.
2016-12-2
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MavicNewbie
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DJI-Ken Posted at 2016-12-2 16:34
Sync your flight records and star the flight as a favorite.
What is your email ?

Hi @DJI-Ken,

Thanks for the promptly reply.
My email is [REMOVED]. I hope I synced the record/favorite right, if not, the flight was on 11/27/2016 @ 22:15:24 .
It was drifting on that day and totally lost control in the last few mintues.
I am still really new poilt. Please let me know if I did somthing wrong.

Thanks!
2016-12-2
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DJI-Ken
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Danny-B- Posted at 2016-12-2 14:22
Cheers Ken, pretty sure compass is spot on i calibrated it properly. Im sure it would have flew aw ...

Danny,
I'm looking at your account and I only see 4 flights and they are all in that large field and I do not see a church. I do not see any errors, the only thing I see is you some Sport Mode and Active Track flights.
I do not see any GPS loss.
Have you synced your records.
2016-12-2
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Danny-B-
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DJI-Ken Posted at 2016-12-2 21:53
Danny,
I'm looking at your account and I only see 4 flights and they are all in that large field a ...

Thatll be right, 4 flights total and itll be my thrid flight with the largest distance. I circle a church towards the end then bring it close to the home point ... the times in the first post are when it flicked to atti mode loosing the gps sync

I have starred the flight now btw
2016-12-2
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DJI-Ken
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MavicNewbie Posted at 2016-12-2 14:48
Hi @DJI-Ken,

Thanks for the promptly reply.

I really don't see any loss of control, I see just a few seconds of weak GPS but the aircraft did not drift since you were only 10ft up for the entire flight.
If you playback your flight an tap the RC icon it will overlay your stick movements and you can see the aircraft moves exactly as your stick inputs.
I do not see a crash, I see you lowered the throttle.
I see numerous flights after that flight, so nothing was damaged in the crash?
2016-12-2
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DJI-Ken
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Danny-B- Posted at 2016-12-2 14:56
Thatll be right, 4 flights total and itll be my thrid flight with the largest distance. I circle a ...

I see it now, it may be the angle of the Mavic as you were in Sport Mode an just went to full forward and that's when it lost GPS.
If you connect the aircraft to the Assisant2 and download the DAT file of the flight, then upload it to Dropbox I will have the flight data analyzed.
2016-12-2
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MavicNewbie
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DJI-Ken Posted at 2016-12-2 17:18
I really don't see any loss of control, I see just a few seconds of weak GPS but the aircraft did  ...

Thanks, yeah it was not a destructive crash.

After playing back I realize perhaps I was mistakenly thinking the `throttle down` as `go backward`. At that time the drone hit a car, then went under the car and crashed around under it.

I took it out see some scratches and all propeller became unusable.

Sorry I didn't analysed it before asking you. Thanks for your time.

But if you took a brief look at the flight log that night, the drone was drifting circularly with good GPS signal. Is that normal during night with a fine (at least no warning) GPS signal?
2016-12-2
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DJI-Ken
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MavicNewbie Posted at 2016-12-2 15:32
Thanks, yeah it was not a destructive crash.

After playing back I realize perhaps I was mistakenl ...

After a crash I would do a IMU and compass calibration.
Try that and see what happens.
2016-12-2
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MavicNewbie
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DJI-Ken Posted at 2016-12-2 17:37
After a crash I would do a IMU and compass calibration.
Try that and see what happens.

I think IMU calibration requires a `precisely level` surface so I did't try that yet.

Just read some tricks to make a level surface -- I will try it, again, that you.
2016-12-2
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DJI-Ken
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MavicNewbie Posted at 2016-12-2 15:43
I think IMU calibration requires a `precisely level` surface so I did't try that yet.

Just read s ...

Your kitchen table will be fine if it's level., but feel free to make something that's exactly level.
2016-12-2
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Danny-B-
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DJI-Ken Posted at 2016-12-2 22:26
I see it now, it may be the angle of the Mavic as you were in Sport Mode an just went to full forw ...

I see where you're coming from Ken, but i was in sports mode and full forward a fair bit before that but i wouldnt be suprised if the angle has something to do with it ...

I have now uploaded the .DAT file to dropbox (i hope its the right file)

https://www.dropbox.com/s/ql0lad ... 3-00-10%5D.DAT?dl=0

Let me know if you need any more info,

Cheers,
2016-12-2
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DJI-Ken
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Danny-B- Posted at 2016-12-2 16:24
I see where you're coming from Ken, but i was in sports mode and full forward a fair bit before th ...

Ok, thanks.
I'll have them look at it Monday.
2016-12-2
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hbax450
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Brand new Mavic, first few flights had this same issue.  Seems to happen when I fly in sport mode.  Scary as heck.  I turned off sport mode, had almost 20 satellites, and wasn't able to use active track due to an error message indicating week GPS signal. Not sure I really trust this thing.
2017-2-11
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hbax450
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Should also mention that in the very beginning of the flight I found it odd that the gimbal was off--roll was way off the horizon despite taking off from a flat surface.  I had to calibrate the roll by incrementing then decrementing the value to get it to fix itself.
2017-2-12
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Danny-B-
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This is a fairly old thread now, but i never received any reply or answer from DJI, or DJI-Ken regarding this enquiry, which is a bit of a shame ...

The issue was supposed to be fixed with the latest version of the firmware as its now supposed to use the secondary compass where before it wouldn't
2017-2-12
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