How to read flight data?

cstangor · Feb 27, 2020

Hello,

New Mavic Pro pilot here. I was on my fifth or so flight tonight and it was windy. But I never got any wind warnings.

I was lucky I think I could turn the craft around toward me as it started to blow away. As far as I could tell it was a dead heat between the wind and the craft. I was eventually able to land it (but downwind from the home point).

(But perhaps I am completely misunderstanding what happened)

I have my flight logs in airdata but how can I drill down and see what was happening and whether I missed some notifications.

Should I use CsvView or do I pay for an airdata subscription? Or is there still a better way.

Thanks in advance.

slup · Feb 28, 2020

Start with going here --> Flight log retrieval and analysis guide and read up on the subject.

Gaining access to wind speeds during the flight from the TXT log in Airdata.com requires a paid subscription. If you then anyway want the community support you need to as a start at least post up your TXT log.

cstangor · Feb 28, 2020

slup said:
Start with going here --> Flight log retrieval and analysis guide and read up on the subject.

Gaining access to wind speeds during the flight from the TXT log in Airdata.com requires a paid subscription. If you then anyway want the community support you need to as a start at least post up your TXT log.

Thank you.

I have read the Flight log retrieval and analysis guide but don't yet understand if the referenced ".txt" or ".dat" files are available through airdata. I have "KML," "GPX," "CSV", and "Original." None of which are .dat or .txt. Do I need to plug in the drone to get these?

slup · Feb 28, 2020

The TXT & DAT log always remain in the mobile device you used for the flight ... if you again go here --> Flight log retrieval and analysis guide ( & read under point 3 & the sections there Mobile device DJI TXT logs and Mobile device DAT files (DJI GO 4 & DJI Fly).

You can then chose to provide Airdata.com (or other online services) the TXT log ... either by just retrieve it from you mobile & upload it manually there or sync your flights in the GO4 app to DJI servers & set up your Airdata account to retrieve it from the DJI servers. The DAT log will not be handled by Airdata.

If pushing "Original" under the map in Airdata the original TXT log will be downloaded to the device you are using to access Airdata (Phone, Tab or Computer).

cstangor · Feb 28, 2020

Thanks.

Yes, it seems to be the airdata "original" that creates the ".dat" (or is it the ".txt"?) file even though it saves it as ".csv." (easy to be confused

.

I renamed the ".csv" file to ".dat" and attached it (the forum does not allow .csv uploads).

I'm trying to understand the period after I took the second photo and the craft suddenly started moving east. I definitely was not trying to fly east, but the wind was out of the west and pretty strong.

Did I contribute to the eastward flight or did I slow it down?

In retrospect I was thinking I should have used RTH but the return home altitude was 100ft and I was thinking (the best I could as my new drone was flying away) "lower is better."

Thank you again.

cstangor · Feb 28, 2020

Oh, sorry, I guess I sent the .txt file. You explained that in your 2nd message.

sar104 · Feb 28, 2020

slup said:
The TXT & DAT log always remain in the mobile device you used for the flight ... if you again go here --> Flight log retrieval and analysis guide ( & read under point 3 & the sections there Mobile device DJI TXT logs and Mobile device DAT files (DJI GO 4 & DJI Fly).

You can then chose to provide Airdata.com (or other online services) the TXT log ... either by just retrieve it from you mobile & upload it manually there or sync your flights in the GO4 app to DJI servers & set up your Airdata account to retrieve it from the DJI servers. The DAT log will not be handled by Airdata.

If pushing "Original" under the map in Airdata the original TXT log will be downloaded to the device you are using to access Airdata (Phone, Tab or Computer).

Just a slight correction - AirData will read mobile device DAT files.

sar104 · Feb 28, 2020

cstangor said:
Thank you.

I have read the Flight log retrieval and analysis guide but don't yet understand if the referenced ".txt" or ".dat" files are available through airdata. I have "KML," "GPX," "CSV", and "Original." None of which are .dat or .txt. Do I need to plug in the drone to get these?
View attachment 95297

To clarify, the log guide that you read primarily discusses manual retrieval of the log files from your mobile device. If you have set up to auto upload flight logs to AirData then that will be the txt log (not the DAT file - you would need to upload that manually), and you can then download that from AirData as the linked "Original" if that is more convenient. It's still on your mobile device, however.

sar104 · Feb 28, 2020

cstangor said:
Thanks.

Yes, it seems to be the airdata "original" that creates the ".dat" (or is it the ".txt"?) file even though it saves it as ".csv." (easy to be confused .

I renamed the ".csv" file to ".dat" and attached it (the forum does not allow .csv uploads).

I'm trying to understand the period after I took the second photo and the craft suddenly started moving east. I definitely was not trying to fly east, but the wind was out of the west and pretty strong.

Did I contribute to the eastward flight or did I slow it down?

In retrospect I was thinking I should have used RTH but the return home altitude was 100ft and I was thinking (the best I could as my new drone was flying away) "lower is better."

Thank you again.

This file is AirData's partial conversion of the txt log to csv format. It's not the original txt log and it is missing many of the important data fields. If you want log analysis help then you need to upload the original txt log to the forum.

slup · Feb 28, 2020

Aha ... you were flying with Litchi, you didn't say that.

Then again from here --> Flight log retrieval and analysis guide ( & read under point 2 Mobile device third-party control app log files and point 3 but now in the section Litchi log files) .

Made a copy directly here below from there ...

From point 2:

Mobile device third-party control app log files

Third-party control apps, such as Litchi, create their own custom log files in various formats using the DJI SDK, generally in CSV format. None that I have seen are as comprehensive as the DJI TXT log, let alone the DJI DAT log.

Since Litchi is probably the most common third-party app, it's worth noting that, under iOS and Android, Litchi creates its own CSV log and a standard DJI TXT log in a separate directory. No DAT file though.

From point 3:

Litchi log files

On iOS devices, the Litchi CSV logs are in Litchi » Documents » flightlogs, and the DJI TXT logs are in Litchi » Documents » SDK_logs » FlightRecord.

On Android devices the Litchi CSV logs are in LitchiApp » flightlogs. Litchi also creates a standard DJI TXT log, which for some reason it stores in a subdirectory in the DJI app directory, DJI » com.aryuthere.visionplus » FlightRecord.

No DAT logs are created when flying with Litchi ... So meaning no way to access raw sensor data or motor data.

But yeah ... this was a "BlowAway"

The winds:

From the last photo height and speed sideways in wind direction.

Your corresponding stick inputs:

You descended ... that's what saved you. Initiated RTH have most probably been really bad.

cstangor · Feb 28, 2020

Hey thanks a lot slup... This will take some time to digest but I'm sure I'll be back later today

Is there a column in the .txt data that shows the craft's orientation (East/West/North/South)?

I'm wondering why I didn't get any wind warnings through Litchi.

sar104 · Feb 28, 2020

cstangor said:
Hey thanks a lot slup... This will take some time to digest but I'm sure I'll be back later today

Is there a column in the .txt data that shows the craft's orientation (East/West/North/South)?

I'm wondering why I didn't get any wind warnings through Litchi.

That's the field labeled "Yaw", in degrees relative to true north.

slup · Feb 28, 2020

Here how the yaw angle from 0 degrees (North) looked like during the flight ...

sar104 · Feb 28, 2020

cstangor said:
Hey thanks a lot slup... This will take some time to digest but I'm sure I'll be back later today

Is there a column in the .txt data that shows the craft's orientation (East/West/North/South)?

I'm wondering why I didn't get any wind warnings through Litchi.

If you want to see the warnings produced by the SDK then you need to see if you can find the txt log that I mentioned above, which when Litchi is running should be in the DJI app directory:

DJI » com.aryuthere.visionplus » FlightRecord