Lost my DJI Mavic pro on my first flight [ DRONE FOUND]

[Cyberpower678]

Thank you everyone again, I really appreciate your help and your time, without you I would never find it. Such a good people, helping for nothing, such a good community! I love you all I'm now even more happy than when I bought it. I don't know why, at the moment my drone is in the rice and I even don't know if is gonna fly or not, but I'm so happy

Now go and add a big "FOUND" to your title to claim your victory.

 

[CaryTheLabelGuy]

Wow. Unbelievable! Congrats to all involved.

This community has some really bright and kind people in it! I’ve been following this thread from the beginning. Congrats again!

Side note: I guess we now know for sure that if the Mavic goes into forced ATTI mode due to compass errors and/or IMU issues, when RC connection is lost, it will auto-land.

 

[msinger]

OK, I'm glad that I hadn't missed anything that fundamental. In that case how is it known that it behaves like that?

I guess it's not known by most people. I only know DJI drones work this way from reviewing countless flight logs.

 

[msinger]

I can't believe I found it this morning 30 meters away from your pin. Thank you very much!!! You can't believe how happy I am now.

You're welcome. I'm happy to see you were able to track it down

 

[msinger]

Side note: I guess we now know for sure that if the Mavic goes into forced ATTI mode due to compass errors and/or IMU issues, when RC connection is lost, it will auto-land.

You got it. This is how all DJI drones work.

 

[rfc]

Wow. Unbelievable! Congrats to all involved.

This community has some really bright and kind people in it! I’ve been following this thread from the beginning. Congrats again!

Side note: I guess we now know for sure that if the Mavic goes into forced ATTI mode due to compass errors and/or IMU issues, when RC connection is lost, it will auto-land.

Add my kudos to the smart folks here.

Will the auto-land happen if the Mavic is in ATTI mode OTHER than "due to compass errors and/or IMU issues"?
I've thought of testing this myself on a totally calm day, doing the aluminum foil ATTI thing with the A/C perhaps 10m up and very close, in a large field, then shut off the R/C. Should it land immediately?

If so, could this be added to the list of possible "last ditch" emergency procedures? I.e. intentionally shutting off the R/C if you think you have a chance of landing it somewhere you know it is (vs. letting it go off into the boondocks?)

 

[msinger]

Will the auto-land happen if the Mavic is in ATTI mode OTHER than "due to compass errors and/or IMU issues"?

Yes.

 

[sar104]

Yes.

That's another interesting question that I've seen various answers to. In the course of trying to hunt down the answer to this situation I found a number of quite definite statements that failsafe RTH works in regular ATTI mode if the aircraft has enough satellites locked - i.e the aircraft will return home - again not particularly intuitive. I've also read that setting one of the two g_config_control_mode parameters to 9 (as opposed to 3 for ATTI) accesses ATTI mode with RTH capability, which would tend to support your comment that in regular ATTI it should not RTH.

That one presumably we can test simply by hitting the RTH button in ATTI mode - that I am willing to do.

 

[rfc]

That's another interesting question that I've seen various answers to. In the course of trying to hunt down the answer to this situation I found a number of quite definite statements that failsafe RTH works in regular ATTI mode if the aircraft has enough satellites locked - i.e the aircraft will return home - again not particularly intuitive. I've also read that setting one of the two g_config_control_mode parameters to 9 (as opposed to 3 for ATTI) accesses ATTI mode with RTH capability, which would tend to support your comment that in regular ATTI it should not RTH.

That one presumably we can test simply by hitting the RTH button in ATTI mode - that I am willing to do.

I just thought of a flaw in my plan, which calls for taking off in ATTI mode, not flying in P-GPS mode then slipping into ATTI mode. The A/C can't set a home position in ATTI mode, can it? This would probably be easier to test with a P3 or P4.

 

[Cyberpower678]

In theory the DJI drone's have the hardware to actually run without GPS, it's just that the engineers are too lazy to implement it. Since the Mavic has a compass and IMU, it can just use the current position as 0,0 coordinates in an internal grid and then using the IMU and heading information move it's coordinates around based on the IMU motion. It's not as accurate as a GPS, but if implemented would allow the drone to continue function as close to GPS mode as possible, even allowing for failsafe RTH without GPS to be possible.

 

[MAvic_South_Oz]

Great result, so good to hear you found it.
@msinger and @sar104 great input.

 

[waddellw]

Awesome guys. So glad you found it. Truly awe inspiring.

My controller disconnected day 2 of messing around and mine shot straight up and went over 40 feet back to home and set itself down, I guess I got lucky!


My buddy had a phantom 1 back when they were new and hot and switched it into atti mode up in the wind because somebody on a forum said it would hadle the wind better and it took off so fast and wouldn't reconnect. We found it a day later in a field, the fact that it is white really helped out. But believe it or not even with countless wrecks logged his phantom 1 still flies. That's the kind of durability I hope for!

 

[Bogey]

I have to admit, 80% of this thread was over my head but still a chance to learn so I kept reading; learned a little and got to witness some 1st class people helping someone they don’t know - impressive! [emoji41]

 

[DavidGlennPDX]

I am rooting for the drone to be 100% ok. Unless there was a strong rain or it crashed I am thinking it should do well. Hell, even a strong rain would I think still give it a fair chance from what I have seen.

 

[Govorin]

Do you think guys is going to be fine to try to fly with it again or send it back to dji straight away ? Maybe someone can recommend me something..

 

[sar104]

In theory the DJI drone's have the hardware to actually run without GPS, it's just that the engineers are too lazy to implement it. Since the Mavic has a compass and IMU, it can just use the current position as 0,0 coordinates in an internal grid and then using the IMU and heading information move it's coordinates around based on the IMU motion. It's not as accurate as a GPS, but if implemented would allow the drone to continue function as close to GPS mode as possible, even allowing for failsafe RTH without GPS to be possible.

This seems like a reasonable idea for situations where the cause of ATTI is insufficient GPS data - obviously it's not going to work in situations like this one where it is the IMU that is compromised (unfortunately the most common). I agree that the drift in the gyros and accelerometers should be small enough to be tolerable over short periods.

It's easy enough to test since the raw sensor data are available in the DAT files, so for a P-GPS flight one can compute predicted position based purely on the IMU and then compare to the actual GPS location. I've been meaning to do that for some time.

 

[sar104]

Great result, so good to hear you found it.
@msinger and @sar104 great input.

Thanks, although I learned more than I contributed since I was unaware that autoland was the immediate failsafe action when RTH is not available due to ATTI.

 

[ozark]

I don't know how to say thanks to you, I would give you million likes if I can, I can't believe I found it this morning 30 meters away from your pin. Thank you very much!!! You can't believe how happy I am now. I'll make a video of my story finding a drone and how I find and where it was, I have some material. Thanks a lot. You're the best of the best, so smart!! I would like to meet you in real and shake your hand and buy you a drink now my drone is in 6kg of rice, just wait for video if you're interested

I just joined the group the other day and this was the first thread I latched onto since I am a new Mavic owner. First off, Govorin's initial flight was quite an experience that I am sure glad I didn't have to experience. As a new drone owner, I really learned a lot from this thread and look forward to the analytical conclusion. You guys really know your stuff and I look forward to your insights in the future. Thanks!

 

[MavicMoira]

Do you think guys is going to be fine to try to fly with it again or send it back to dji straight away ? Maybe someone can recommend me something..

The first thing to do when your MP is fully dried out is to do calibrations of everything - compass, IMU, gimble - make sure that you are away from any possible magnetic interference when calibrating the compass including watch/phone & any other metal.

I am so glad you found your MP and much kudos to msinger for his accurate estimation.

 

[tccraiger]

Great job msinger... you da man!