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Get the wind data from Mavic 2 Zoom?

Smilingz

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Hi!
This is my first post on the forum so pardon me if it's in the wrong place.

We have a project in university where the tasks are to collect the wind data (speed and direction) in real time, feed that data and reference data from other telemetry devices into a neural network to get better estimates than what the drone can make.

We've read that DJI Drones store their flight data, but they are encrypted.
As such we need to find some kind of program that can decrypt the flight logs of the wind direction and speed that is stored after a flight so that it then can be sent to our neural network for training. So we're basically looking for a program that can decrypt those flight logs, any advice?

As said in the title, our drone is the DJI Mavic 2 Zoom :)

Have a fly day!

Alex
 

Keule

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Smilingz

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Thank you very much, just what we're looking for! Do you have any knowledge if one of the parameters stored is wind direction and speed?
Our approach could be different depending on. If it's stored it might make the data feed easier, otherwise we would need the attitude data and do some math on it to make a proper feed of the data.
 

Keule

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Thank you very much, just what we're looking for! Do you have any knowledge if one of the parameters stored is wind direction and speed?
Our approach could be different depending on. If it's stored it might make the data feed easier, otherwise we would need the attitude data and do some math on it to make a proper feed of the data.
There is no wind data stored in the AC.
You might read ahead this thread: Mavic Mini Wind Calcs
 

BudWalker

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Hi!
This is my first post on the forum so pardon me if it's in the wrong place.

We have a project in university where the tasks are to collect the wind data (speed and direction) in real time, feed that data and reference data from other telemetry devices into a neural network to get better estimates than what the drone can make.

We've read that DJI Drones store their flight data, but they are encrypted.
As such we need to find some kind of program that can decrypt the flight logs of the wind direction and speed that is stored after a flight so that it then can be sent to our neural network for training. So we're basically looking for a program that can decrypt those flight logs, any advice?

As said in the title, our drone is the DJI Mavic 2 Zoom :)

Have a fly day!

Alex
There are a couple of options. Have you tried using the wind calcs available at
airdata.com

There is also the wind calcs done by the M2Z Flight Controller and then recorded in the .DAT created by the DJI 4 App. Currently, those wind calcs are a bit harder to get.

1) retrieve the tablet .DAT log file How to retrieve a V3.DAT from the tablet
2) Download/install CsvView CsvView Downloads
3) When you run CsvView you'll need to tell it that you also want the DatDefined signals
1581687362540.png
4) Create an Empty SigPlayer and then populate it with these wind calc data
1581687772200.png

The Export .csv feature can be used to create a .csv that contains those wind calcs data
1581687902966.png
 
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AMann

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Realtime? May want to attach a ultrasonic anemometer to the top of it- I looked into a small one from a Chinese company that could be mounted on top of a M2P and it sent real-time telemetry for a windfarm project, but the contract closed and I since cant find their info online. Google “realtime wind measurement with drones” or something like that.
 

Smilingz

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There are a couple of options. Have you tried using the wind calcs available at
airdata.com

There is also the wind calcs done by the M2Z Flight Controller and then recorded in the .DAT created by the DJI 4 App. Currently, those wind calcs are a bit harder to get.

1) retrieve the tablet .DAT log file How to retrieve a V3.DAT from the tablet
2) Download/install CsvView CsvView Downloads
3) When you run CsvView you'll need to tell it that you also want the DatDefined signals
View attachment 93922
4) Create an Empty SigPlayer and then populate it with these wind calc data
View attachment 93924

The Export .csv feature can be used to create a .csv that contains those wind calcs data
View attachment 93925
Thank you very much BudWalker! I'll send this over to my group member that has the drone to see what he wants to make of it. Is the data updated very frequently or is it much slower, say only once per second?
Have a great day :)
 
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Smilingz

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Realtime? May want to attach a ultrasonic anemometer to the top of it- I looked into a small one from a Chinese company that could be mounted on top of a M2P and it sent real-time telemetry for a windfarm project, but the contract closed and I since cant find their info online. Google “realtime wind measurement with drones” or something like that.
Yes, not necessarily real time, to train our neural network we need a lot of data! If we can't get it recorded in real-time then all that is needed is to time-synchronize the reference telemetry with the drones telemetry. The biggest problem is that we need A LOT of data, which is why I'm hoping that it updates these parameters atleast 10 times per second.

But real-time would be even better, since it would further increase our efficiency, I'll definitley look into it! Thank you for you help and have a great day :)
 

AMann

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Yes, not necessarily real time, to train our neural network we need a lot of data! If we can't get it recorded in real-time then all that is needed is to time-synchronize the reference telemetry with the drones telemetry. The biggest problem is that we need A LOT of data, which is why I'm hoping that it updates these parameters atleast 10 times per second.

But real-time would be even better, since it would further increase our efficiency, I'll definitley look into it! Thank you for you help and have a great day :)

also look at wireless crane anemometers- there are small ones that can be mounted to a Mavic or Phantom
 

BudWalker

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Thank you very much BudWalker! I'll send this over to my group member that has the drone to see what he wants to make of it. Is the data updated very frequently or is it much slower, say only once per second?
Have a great day :)
The frequency depends on the data. Since this is a tablet .DAT the fastest frequency possible will be 10 Hz. Looks to me like the windSpeed is 0.05 Hz while the windDir is probably 10 Hz. Sensors like gyro and accelerometer data are 10 Hz. Pitch, roll, tiltInclination and tiltDirection are also 10 Hz.
 
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slup

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There are a couple of options. Have you tried using the wind calcs available at
airdata.com

There is also the wind calcs done by the M2Z Flight Controller and then recorded in the .DAT created by the DJI 4 App. Currently, those wind calcs are a bit harder to get.

1) retrieve the tablet .DAT log file How to retrieve a V3.DAT from the tablet
2) Download/install CsvView CsvView Downloads
3) When you run CsvView you'll need to tell it that you also want the DatDefined signals
View attachment 93922
4) Create an Empty SigPlayer and then populate it with these wind calc data
View attachment 93924

The Export .csv feature can be used to create a .csv that contains those wind calcs data
View attachment 93925
A bit of topic ... @BudWalker, do you know if similar data exists for other DJI models?

Found this in one of my DAT logs from an MA ... couldn't find anything regarding wind direction though.

MA Wind.jpg
 

BudWalker

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A bit of topic ... @BudWalker, do you know if similar data exists for other DJI models?

Found this in one of my DAT logs from an MA ... couldn't find anything regarding wind direction though.

View attachment 93976
I suspect that wind_X and wind_Y are actually wind_N and wind_Y respectively. I.e. windDir would be atan2(wind_Y, wind_X). If you can confirm that (maybe by comparing to AirData) I'll put that calc in the next version.
 

slup

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I suspect that wind_X and wind_Y are actually wind_N and wind_Y respectively. I.e. windDir would be atan2(wind_Y, wind_X). If you can confirm that (maybe by comparing to AirData) I'll put that calc in the next version.
Great ... will see what can be collected during this weekend.
 

slup

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@BudWalker ... I flew a shorty today, the wind & especially the gusts were a bit on the higher side so it was only a shorter lap around the neighborhood at 30 meters height.

The winds were approx south westerly on ground... so negative wind_x(North) & wind_y(East).

On the 65sec mark in the chart:

Angle from west=tan−1(-6,3/-8,59)≈ -36,26 degrees
Angle from north=270-36,26 = 233,74 degrees

... this is pretty consistent throughout the lap. It differs a bit from Airdata indication which is 218 degrees at that point, but match better Airdatas average direction of 223 degrees. The magnetic declination where I live is 5,53 degrees east.

Have attached the DAT log


Test.jpg

Airdata.jpg
 

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  • 20-02-15-10-37-47_FLY087.DAT
    3.2 MB · Views: 3
Last edited:

Smilingz

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The frequency depends on the data. Since this is a tablet .DAT the fastest frequency possible will be 10 Hz. Looks to me like the windSpeed is 0.05 Hz while the windDir is probably 10 Hz. Sensors like gyro and accelerometer data are 10 Hz. Pitch, roll, tiltInclination and tiltDirection are also 10 Hz.
Ok thank you for the help :) Then reading the other parameters and using either 3rd party solutions or our own calculations to wind speed and direction might be our best option to get high frequency data.
 

sar104

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@BudWalker ... I flew a shorty today, the wind & especially the gusts were a bit on the higher side so it was only a shorter lap around the neighborhood at 30 meters height.

The winds were approx south westerly on ground... so negative wind_x(North) & wind_y(East).

On the 65sec mark in the chart:

Angle from west=tan−1(-6,3/-8,59)≈ -36,26 degrees
Angle from north=270-36,26 = 233,74 degrees

... this is pretty consistent throughout the lap. It differs a bit from Airdata indication which is 218 degrees at that point, but match better Airdatas average direction of 223 degrees. The magnetic declination where I live is 5,53 degrees east.

Have attached the DAT log


View attachment 94006

View attachment 94007

I don't see those "air_compensate" data fields in the DAT file that you posted. The "air_comp" fields are there, but don't correspond well to your data. They do correspond approximately with the AirData values:

Graph0.png
 

slup

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I don't see those "air_compensate" data fields in the DAT file that you posted. The "air_comp" fields are there, but don't correspond well to your data. They do correspond approximately with the AirData values:

View attachment 94021
Did as @BudWalker said, went into DatCon Parsing options & ticked Engineered & Datdefined ... & then I got those signals. the Airdata & those frome the DAT differs but can't say which is more accurate.

2020-02-15_16-04-05.jpg
 
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