DJI Mavic, Air and Mini Drones
Friendly, Helpful & Knowledgeable Community
Join Us Now

Analyzing data / flight files

Turn11

Well-Known Member
Joined
Dec 1, 2017
Messages
1,095
Reactions
462
Location
Bullhead City, Arizona, USA
The data are extracted from either the onboard .DAT files or the device .txt logs using DatCon (for DAT files) or the PhantomHelp / AirData websites for basic fields from the .txt logs. For more detailed output from the .txt logs I use TXTlogToCSVtool.

Then you need a data analysis package to analyze and visualize the data; I use Wavemetrics Igor Pro, but you could equally well use MatLab or similar.

Alternatively, you can skip all that and use @BudWalker's CsvView for DAT files and .txt logs, which uses a different approach to data visualization by creating "players" but works very well.

I copied the above post from a thread about a lost drone and reading “data files” and interpreting what was the cause. Ocean Crash – Resolved #47

I am a newbie to drones and RC flying. I have roughly 2.5 hours flight time. I have done a LOT of reading and a lot of reference is made to the data files and seeing what went on during the flight. In my spare time I would like to learn the basics and what tools to use. I hope that is a reasonable goal. I parsed the above thread and used google to search for information.

Directions on finding flight logs for Apple & Android can be found in this thread

Could I get some direction on which files to analyze and which tools to use. Pros & Cons of the tools.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
data are extracted from either the on board .DAT files or the device .txt logs using DatCon (for DAT files)
or the PhantomHelp / AirData websites for basic fields from the .txt logs
For more detailed output from the .txt logs I use TXTlogToCSVtool
data analysis package to analyze and visualize the data; I use Wavemetrics Igor Pro
you could equally well use MatLab or similar
Alternatively, you can skip all that and use @BudWalker CsvView for DAT files and .txt logs

Here is a screen copy of DJI GO 4 Apple iPad Air File Sharing folder (Oops I did something wrong)
 

Attachments

  • Ipad file sharing cropped      .jpg
    Ipad file sharing cropped .jpg
    86.2 KB · Views: 49
Last edited:
I can expand a bit on that - I wrote this summary (slightly updated here) recently in response to a similar question:

There are two primary kinds of log files: (1) the mobile device .txt log files that are accessed using iTunes or similar (e.g. iExplorer) for iOS or through the Android file system and (2) the aircraft DAT files that are accessed via DJI Assistant 2 connected to the aircraft. Instructions for retrieving the files are on the PhantomHelp webpage for .txt logs and on the DatCon website for the DAT files.

The DAT files are far more comprehensive but obviously are only available with access to the aircraft. They contain all telemetry and operating parameters. Most notably they include motor performance data and raw IMU sensor data that are missing from the .txt files, and have sample rates of up to 200 samples/s, depending on the parameter, as opposed to 10 samples/s for .txt data. Those particular data are often key to figuring out the cause of crashes and flight failures.

Just to add some confusion, there are also DAT files created on the mobile device that contain different data than the .txt log files, but those are rarely more use than the device .txt logs.

Both kinds of file are encrypted and need to be decoded in order to use them:

I'm aware of only two options for DAT files - either DatCon or CsvView, both written by @BudWalker and available for Mac and Windows. DatCon converts to .csv, while CsvView is both a converter and data visualization tool.

For .txt log files, the commonest ways to decode is via the PhantomHelp website or the AirData website, both of which only do a partial conversion of the data and an even more limited display of the data. PhantomHelp currently also seems to have some problems with the Mavic files that result in misleading data. To get the most out of the converted files you need to download the .csv and .kml files that both sites offer after conversion. You can also use @ferraript's TXTlogToCSVtool.exe application that decodes many more data fields from the .txt files. CsvView (but only the Windows version) will also process and display .txt log data.

Having decoded either kind of file, you then need to analyze and visualize the data. CsvView has very nice visualization tools but does not do data analysis (filtering, fitting, FFT, extrapolation etc.). For those purposes I take the converted .csv data files from DatCon, TXTlogToCSVtool.exe, PhantomHelp or AirData and import them into Wavemetrics Igor Pro, which is my preferred analysis software. You could also use MatLab or Synergy's Kaleidagraph. All are commercial software, but I'm not aware of any free alternatives. Kaleidagraph is the cheapest at $199. Excel will produce graphs so might be a possibility if you only need to view the data.
 
Hi, Im new here and try to find out how to interpret data from my Mavic Air without leaving all my data intentionally to chinese servers. When I found the DatCon and CsvView and was looking forward to have the tools. But when downloading then I only recognized that:
1. the Mavic Air Dat file is not supported (as it is crypted)
2. even if I will use the Dat file from my phone (RC DAT file) Im unlucky to have Windows 7 in the 32bit version (as both utilities require 64bit Java)
Am I right in my conclusions?
It seems that the only way which remains to me is using the TXTlogToCSVtool.exe .
 
Last edited:
Hi, Im new here and try to find out how to interpret data from my Mavic Air without leaving all my data intentionally to chinese servers. When I found the DatCon and CsvView and was looking forward to have the tools. But when downloading then I only recognized that:
1. the Mavic Air Dat file is not supported (as it is crypted)
2. even if I will use the Dat file from my phone (RC DAT file) Im unlucky to have Windows 7 in the 32bit version (as both utilities require 64bit Java)
Am I right in my conclusions?
It seems that the only way which remains to me is using the TXTlogToCSVtool.exe .
Yes, that's correct. CsvView and DatCon both require a 64 bit Java to run.
 
Yes, that's correct. CsvView and DatCon both require a 64 bit Java to run.
Bud, Thank you for your reply.
Anyway in the end I installed your CsvView and DatCon progams to PC of my friend (64bit version of Win 7) and tried the CSVView. And Im happy to say that the point 1. of my previous post is not true. The CsvView reads the Dat file from Mavic Air without problems. I will now correct the point 1. accordingly.
So probably the warning written in red color on the page "Retrieving a V3 .DAT File from the AC" on How to retrieve a V3 .DAT File from the AC is happily no more true. Would you please check this?

I must say that the CsvView seems to mee to be very useful program. Thank you.
 
Last edited:
Bud, Thank you for your reply.
Anyway in the end I installed your CsvView and DatCon progams to PC of my friend (64bit version of Win 7) and tried the CSVView. And Im happy to say that the point 1. of my previous post is not true. The CsvView reads the Dat file from Mavic Air without problems. I will now correct the point 1. accordingly.
So probably the warning written in red color on the page "Retrieving a V3 .DAT File from the AC" on How to retrieve a V3 .DAT File from the AC is happily no more true. Would you please check this?

I must say that the CsvView seems to mee to be very useful program. Thank you.
That's pretty surprising. Actually quite the shocker.
What FW are you running on the Mavic Air?
Which version of the DJI Assistant 2 are you using?
Can you please Dropbox a .DAT that you've retrieved from the Mavic Air.
 
Im sorry that I madechaos here, it was DAT file from the phone (from MCDatFlightRecords folder) :(
Its confusing the number of files which seem to be simillar but differ totally.
 
  • Like
Reactions: BudWalker
Im sorry that I madechaos here, it was DAT file from the phone (from MCDatFlightRecords folder) :(
Its confusing the number of files which seem to be simillar but differ totally.

You’re not the first to be confused by this
 
  • Like
Reactions: GregD
Lycus Tech Mavic Air 3 Case

DJI Drone Deals

New Threads

Forum statistics

Threads
130,593
Messages
1,554,207
Members
159,599
Latest member
jordy