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Mavic pro lost - how can I locate it?

Joined
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#1
Hello guys
i am new here. Unfortunatelly I have lost my Mavic Pro aircraft yesterday and I need your quick help to find it.

I flew the drone from my cherry orchard to a plum ochard which is 7,2 km far away. I used the sport mode with obstacle avoidance disabled.During the flight I ignored the RTH advice which occured when I was at 50% of my battery. I flew with 50-60 -70km per hour speed. I got a meassage with" battery error "once.

I did reach the other orchard at height above 50m or higher. I only had about 20% battery left so I decided to land it there.So I started descending but at some point I have lost the signal. The drone was hoovering.The setting for "lost signal" was " return home".

While I was waiting to get the signal back " a law battery warning" started peeping, which was set at 20%. The last I saw was 16% battery left.

So I stepped on my car drove straight to the plum orchard.While I was driving after 7-8 minutes without a signal I did get back the conection to
to the drone. What I saw was my aircraft sitting somewhere on a tree with leafs and branches around.It only had 2% battery left. I moved the gimbal around , the camera was working and was happy because I thought it has landed in my plum orchard.

I was in s hurry to find it and did not look on my phone to see what is the distance between me and my drone. Finally I got to the orchard and started to look around.I still had contact to my drone with about 1% of battery life left on it. Then finally it switched off. I did not find it nowhere in or around my orchard.

I dont have a tracking device and I also did not have a map activated on the down left corner of the phone( or nld app).

I looked to flight records and this flight was recorded with 7797 km distance.Then I checked the txt file and uploaded it to phantomhelp website . It gave the details of my flight. The last recorded GPS position was just above or just near the orchard. The drone wasnt there. There is no chance of someone picking it because it is in the middle of nowhere.

The last txt file is from 14:55-14-57 which is time of the flight and does not show a return home path on the map.So no return to home path recorded.

My suspicion is that after losing signal it started to go home but at some point the battery was crtically law and it landed somewhere on a tree. Other possibility is it hit a tree because the obstacle avoidance was disabled. As far as I remember the return to home altitude was 30 metres but I am not 100% sure.
The good thing is that it did regain connection for about 10 minutes and even it was not flying but sitting on this tree there must be information about this period.

There is DAT file recorded in the dji folder of my phone which I cannot open.One of them is modified at 15:13 h., obviously the time when the aircraft last switched off.
1.Is there a chance to recover the last GPS position of my drone by reading this DAT file?
2. If this file contailns this information how can I open it, beacause for some reason cvsviewer and datcon do not recognize the file and cannot open it.

.
Please help me!

If this if helpful for you I also recorded my flight on a video on my phone which ends at the point when signal is lost. I can also supply you with all txt or DAT files in my folder.
 

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Meta4

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#2
It looks like you didn't want to get your Mavic back
More than 7km away and 18% battery and you were flying even further away in Sport Mode !!!!!!
The flight data you supplied doesn't help much.
It doesn't show where the Mavic went after 18%.
The Mavic was well above he height of any potential obstacles on the RTH path.
The last txt file is from 14:55-14-57 which is time of the flight and does not show a return home path on the map.So no return to home path recorded.
That is the data that might hold the secret. Can you post it?
 
Last edited:
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sar104

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#5
OK good. The DAT file includes the landing, which occurred at 572 seconds:

Graph0.png

Extracting the location data from the IMU and GPS records gives the following track and landing point:

screenshot226.jpg

Those values disagree by about 12 meters, but you should be able to find it around those points.
 
Joined
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#6
Wow. Incredible sar104! I'm looking up just now on how to map out my flight on google earth or similar. I know there is a "how to" thread somewhere on here, I'm trying to find it.
 
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sar104

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#7
Wow. Incredible sar104! I'm looking up just now on how to map out my flight on google earth or similar. I know there is a "how to" thread somewhere on here, I'm trying to find it.
The simplest way is just to upload the txt flight log to AirData or PhantomHelp and then download the derived kml file, which will open directly in Google Earth.

There was some added complexity in this case in that the txt log stopped before the aircraft auto landed, and so I used the DAT file instead.
 
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#9
The simplest way is just to upload the txt flight log to AirData or PhantomHelp and then download the derived kml file, which will open directly in Google Earth.

There was some added complexity in this case in that the txt log stopped before the aircraft auto landed, and so I used the DAT file instead.
I found the link:
DJI Flight Log Viewer - Phantom Help

Just tried to upload my last flight and downloaded the kml file just like you said and I could view in Google Earth. Incredible!!!!! Exactly what I wanted.

The reason why I wanted it, was I was flying up a mountain this morning. I disabled the 400-ft limit and I attempted to remain within 400-ft above the ground below the drone (instead of 400-ft above my starting position). That is the actual regulation if I understand correctly? Wanted to see if this kml file can help me see if I was able to do it. Not sure if I was successful yet by just looking at it through google earth, I need to see if I can map an elevation profile with the flight vs ground.

Now I will be saving ALL these txt files along with my videos. Should I be saving the DAT files too? Like does it give more information than the txt file that might be useful for troubleshooting? If there is a specific thread that you have a convenient link to that has in depth discussions on these files, can you provide one? I've seen previously on how you have helped determine cause of crash by reading these graphs, etc. I would like to learn more about those graphs.
 

sar104

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#10
I found the link:
DJI Flight Log Viewer - Phantom Help

Just tried to upload my last flight and downloaded the kml file just like you said and I could view in Google Earth. Incredible!!!!! Exactly what I wanted.

The reason why I wanted it, was I was flying up a mountain this morning. I disabled the 400-ft limit and I attempted to remain within 400-ft above the ground below the drone (instead of 400-ft above my starting position). That is the actual regulation if I understand correctly? Wanted to see if this kml file can help me see if I was able to do it. Not sure if I was successful yet by just looking at it through google earth, I need to see if I can map an elevation profile with the flight vs ground.

Now I will be saving ALL these txt files along with my videos. Should I be saving the DAT files too? Like does it give more information than the txt file that might be useful for troubleshooting? If there is a specific thread that you have a convenient link to that has in depth discussions on these files, can you provide one? I've seen previously on how you have helped determine cause of crash by reading these graphs, etc. I would like to learn more about those graphs.
I've not found a simple way to plot AGL given a flight altitude profile. I ended up writing some code to take a ground track elevation profile and compare it with the flight profile.

Hard to say whether it's worth saving all the DAT files. They do contain various data that can be useful in diagnosing changes in performance or behavior, if you want to invest the time to learn how to understand the data.

I haven't seen any comprehensive guides to analyzing the log data, and I've been trying to finish such a guide for nearly a year now. I guess I just need to call it good and post what I have.
 

rfc

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#11
I've not found a simple way to plot AGL given a flight altitude profile. I ended up writing some code to take a ground track elevation profile and compare it with the flight profile.
It must be possible. MapPilot, a flight mission planning/flying software that works with Dronesmadeeasy has an in-app purchase that does just that. I believe it downloads GE data (or mapbox, or something else, and then adjusts the flight path accordingly. Not sure how it could be useful for "manual flying", i.e. not flying on a pre-determined plan with waypoints though.
 

rfc

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#12
OK good. The DAT file includes the landing, which occurred at 572 seconds:
Extracting the location data from the IMU and GPS records gives the following track and landing point:
That looks like it landed exactly in the middle of an old stream bed or irrigation ditch! Good luck!
 

sar104

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#13
@BudWalker - here's something that is puzzling me. In the DAT file above, if you extract seconds from GPS time (which is in hhmmss format) and plot tick number against GPS time, there is a 16 minute gap (11:55 to 12:11) in real time where the tick number apparently doesn't change. There are no data received in that time because the downlink has failed, but isn't the tick number generated on the aircraft and transmitted with the data?

tick.png
 

sar104

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#14
It must be possible. MapPilot, a flight mission planning/flying software that works with Dronesmadeeasy has an in-app purchase that does just that. I believe it downloads GE data (or mapbox, or something else, and then adjusts the flight path accordingly. Not sure how it could be useful for "manual flying", i.e. not flying on a pre-determined plan with waypoints though.
It's certainly possible - my method does it just fine - but I haven't found a website or easy online tool that does the same thing without additional data manipulation.
 

macoman

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#16
It looks like you didn't want to get your Mavic back
More than 7km away and 18% battery and you were flying even further away in Sport Mode !!!!!!
The flight data you supplied doesn't help much.
It doesn't show where the Mavic went after 18%.
The Mavic was well above he height of any potential obstacles on the RTH path.

That is the data that might hold the secret. Can you post it?
It make me realized some folks here think that the Mavic pro battery is indestructible and will be back home after cruising 7km and less than 20% battery life, unbelievable.
 
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DanMan32

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#17
I believe vision sensors are turned back on during RTH, even when in sport mode. In a sense it overrides to P mode during RTH
 

Meta4

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#18
I believe vision sensors are turned back on during RTH, even when in sport mode. In a sense it overrides to P mode during RTH
Your Mavic doesn't RTH in sport mode or any other mode.
RTH is a completely separate flight mode of its own.
 

BudWalker

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#19
@BudWalker - here's something that is puzzling me. In the DAT file above, if you extract seconds from GPS time (which is in hhmmss format) and plot tick number against GPS time, there is a 16 minute gap (11:55 to 12:11) in real time where the tick number apparently doesn't change. There are no data received in that time because the downlink has failed, but isn't the tick number generated on the aircraft and transmitted with the data?

View attachment 49383
I always thought was the case.... But, maybe not.
 

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