MAVIC AIR 2 Logs meaning

[PilotNovel]

Goodmorning to everyone,
I'd like to ask if someone knows what does mean the following features in DJI's log file:
-OSD.hSpeed [MPH] - OSD.hSpeedMax [MPH] - OSD.xSpeed [MPH] -OSD.xSpeedMax [MPH] -OSD.ySpeed [MPH] -OSD.ySpeedMax [MPH] -OSD.zSpeed [MPH] -OSD.zSpeedMax [MPH] -OSD.pitch OSD.roll -OSD.yaw -OSD.yaw [360]

Thanks in advance to who helps me

 

[slup]

Goodmorning to everyone,

I'd like to ask if someone knows what does mean the following features in DJI's log file:

-OSD.hSpeed [MPH] - OSD.hSpeedMax [MPH] - OSD.xSpeed [MPH] -OSD.xSpeedMax [MPH] -OSD.ySpeed [MPH] -OSD.ySpeedMax [MPH] -OSD.zSpeed [MPH] -OSD.zSpeedMax [MPH] -OSD.pitch OSD.roll -OSD.yaw -OSD.yaw [360]

Thanks in advance to who helps me

hspeed = heading speed (horizontal speed in the direction of travel)
Xspeed = speed north, Yspeed = speed east & Zspeed = speed down.
Pitch, Roll & Yaw is the 3 movement axis that makes the aircrafts attitude, see pic below.

Red arrow direction around the movement axis are positive values.



And lastly...

Yaw is measured on a +/- 180 degree scale where 0 is north. Yaw360 is measured on a +360 degree scale where 0/360 is north.

 

[Yorkshire_Pud]

Note, the names used for the various entities, not necessarily the ones you cite, vary depending on which software is used to read the original log. At a guess you might be looking at logs via Phantomhelp's log viewer or CvsView but the names from Airdata may differ.

 

[PilotNovel]

Thank you both for the answers!
Now I'd like to ask you if u know a method to obtain these log files during the flight maybe with some API or with any "weird" technique you know.
Do you also know if there is a method to read the frequency for each rotor of the drone?

Thanks in advance!

 

[slup]

...if u know a method to obtain these log files during the flight

To read off & decrypt the logs "on the fly"? No, never heard of a way to do that.

Mavic drones have in general 3 different types of logs...

The mobile device .TXT log:
Runs from motor start to motor stop (or signal loss), recording telemetry transmitted from the aircraft to the RC at 10 Hz in a few hundred data fields. These logs don't include any raw sensor data - only the IMU solutions that are the output from the sensor fusion algorithm. They also include battery data, gimbal and camera data, flight status and error flags, but no motor data. These logs are stored in the mobile device you fly with.

From the DJI Fly version 1.2.2 the .TXT log got encrypted by DJI ... for a while it was unreadable but then Airdata.com & PhantomHelp.com got the decryption key from DJI & we could use their web service or download their .CSV file for further analysis off line.

The aircraft .DAT log:
These contain the most comprehensive data, logged at the highest rates. A DAT file is started at aircraft power up and continues until power down, and includes numerous boot sequence, sensor calibration and diagnostic data in the flight event stream. There are also hundreds of data fields, many of which are flags or diagnostic computations of unknown types, probably understood only by DJI. However, among these are the raw and processed sensor data and the IMU solution for aircraft attitude, position, velocity and heading, together with battery and motor data, recorded at rates varying from 5 Hz to 200 Hz. The files exist independent of the mobile device control app being used. These logs are stored in the aircraft itself & can be extracted with the program DJI Assistance 2.

On all crafts released after the DJI Mavic Pro (1) the decryption keys are hidden, and so those are not readable except by DJI.

The mobile device .DAT log:
These contain a subset of the aircraft DAT files, including most of the raw sensor data, recorded at a lower data rate of 10 Hz. They are also started at aircraft power up and closed at aircraft shutdown, provided that the app is connected - otherwise it will be the subset of that duration when the app is connected. Not as good as the aircraft DAT files, but nearly as good for most needs, and always available if the control app is either DJI GO4, DJI Fly ... and lately Litchi. These logs are stored in the mobile device you fly with.

The DJI Mini 2 was the first to get the decryption keys hidden for this log, and so those are not readable except by DJI. I don't remember if also MA2 & MA2s DAT's are affected ... but the M3 & Mini 3 Pro are.

...a method to read the frequency for each rotor of the drone?

The motor RPM's are included in either of the 2 .DAT logs.

 

[PilotNovel]

To read off & decrypt the logs "on the fly"? No, never heard of a way to do that.

Mavic drones have in general 3 different types of logs...

The mobile device .TXT log:
Runs from motor start to motor stop (or signal loss), recording telemetry transmitted from the aircraft to the RC at 10 Hz in a few hundred data fields. These logs don't include any raw sensor data - only the IMU solutions that are the output from the sensor fusion algorithm. They also include battery data, gimbal and camera data, flight status and error flags, but no motor data. These logs are stored in the mobile device you fly with.

From the DJI Fly version 1.2.2 the .TXT log got encrypted by DJI ... for a while it was unreadable but then Airdata.com & PhantomHelp.com got the decryption key from DJI & we could use their web service or download their .CSV file for further analysis off line.

The aircraft .DAT log:
These contain the most comprehensive data, logged at the highest rates. A DAT file is started at aircraft power up and continues until power down, and includes numerous boot sequence, sensor calibration and diagnostic data in the flight event stream. There are also hundreds of data fields, many of which are flags or diagnostic computations of unknown types, probably understood only by DJI. However, among these are the raw and processed sensor data and the IMU solution for aircraft attitude, position, velocity and heading, together with battery and motor data, recorded at rates varying from 5 Hz to 200 Hz. The files exist independent of the mobile device control app being used. These logs are stored in the aircraft itself & can be extracted with the program DJI Assistance 2.

On all crafts released after the DJI Mavic Pro (1) the decryption keys are hidden, and so those are not readable except by DJI.

The mobile device .DAT log:
These contain a subset of the aircraft DAT files, including most of the raw sensor data, recorded at a lower data rate of 10 Hz. They are also started at aircraft power up and closed at aircraft shutdown, provided that the app is connected - otherwise it will be the subset of that duration when the app is connected. Not as good as the aircraft DAT files, but nearly as good for most needs, and always available if the control app is either DJI GO4, DJI Fly ... and lately Litchi. These logs are stored in the mobile device you fly with.

The DJI Mini 2 was the first to get the decryption keys hidden for this log, and so those are not readable except by DJI. I don't remember if also MA2 & MA2s DAT's are affected ... but the M3 & Mini 3 Pro are.


The motor RPM's are included in either of the 2 .DAT logs.

Thank you so much,
your answer is so exhaustive!
Can you suggest me an application to open and read .DAT logs? Because they are too heavy and no one of the site that I was using allow me to upload them.

Thank you in advance

 

[slup]

Thank you so much,
your answer is so exhaustive!
Can you suggest me an application to open and read .DAT logs? Because they are too heavy and no one of the site that I was using allow me to upload them.

Thank you in advance

The only usable DAT log from a MA2 (the one stored in the mobile device) isn't "heavy" ... they usually are around 3-5Mb. If it's several hundreds Mb large you have the Aircraft DAT & you will not be able to decrypt it, so unusable.

The free computer program I use to depict the logs is CsvView, download it here --> CsvView Downloads ... it reads both decrypted aircraft DAT's (MP & older models), mobile device DAT's (if they don't come from crafts that have encrypted ones), mobile device .TXT logs (if not created from the DJI Fly app version greater than 1.2.1) & .CSV files downloaded from Airdata.com/PhantomHelp.com.

The program is extensive & have a quite step learning curve ... nothing in it will serve you anything automatically, you need to know a lot of the same thing's as you asked about in the first post in this thread.

 

[PilotNovel]

The only usable DAT log from a MA2 (the one stored in the mobile device) isn't "heavy" ... they usually are around 3-5Mb. If it's several hundreds Mb large you have the Aircraft DAT & you will not be able to decrypt it, so unusable.

The free computer program I use to depict the logs is CsvView, download it here --> CsvView Downloads ... it reads both decrypted aircraft DAT's (MP & older models), mobile device DAT's (if they don't come from crafts that have encrypted ones), mobile device .TXT logs (if not created from the DJI Fly app version greater than 1.2.1) & .CSV files downloaded from Airdata.com/PhantomHelp.com.

The program is extensive & have a quite step learning curve ... nothing in it will serve you anything automatically, you need to know a lot of the same thing's as you asked about in the first post in this thread.

Thank you again but I didnt get this point: Am I allowed to read (in any wat) the The aircraft .DAT log or not?
Infact I used to exploit airdata.com but it didnt work bc these logs are more than 800MB

 

[slup]

Thank you again but I didnt get this point: Am I allowed to read (in any wat) the The aircraft .DAT log or not?
Infact I used to exploit airdata.com but it didnt work bc these logs are more than 800MB

You can't read aircraft .DAT logs from newer DJI drone models than the Mavic Pro... this as the .DAT logs are encrypted. Only DJI staff can make use of them.

 

[Yorkshire_Pud]

It is a cursed shame that DJI encrypted the DAT's on the drone from, assuming Slup is correct, the Mavic Pro onwards.
I have Drone DAT's from my Phantom 3 and they are useful, not least because they are still recorded (and readable) during a disconnection or in my case a freefall when I switched the motors of in mid flight.

You can also you the software "DatCon" to read the phone's DAT's, it is available on the CsvView website but, to be honest, I generally use CsvView.

 

[PilotNovel]

Thank you both! I really appreciate your comments.
I'll let you know if I can read this log file!

 

[slup]

@PilotNovel ... made a mistake regarding the speeds so I've made some changes in my first post, the X & Y speeds are not relative the aircraft.

 

[riterb97]

hspeed = heading speed (horizontal speed in the direction of travel)
Xspeed = speed north, Yspeed = speed east & Zspeed = speed down.
Pitch, Roll & Yaw is the 3 movement axis that makes the aircrafts attitude, see pic below.

Red arrow direction around the movement axis are positive values.

View attachment 155523

And lastly...

Yaw is measured on a +/- 180 degree scale where 0 is north. Yaw360 is measured on a +360 degree scale where 0/360 is north.

Hi Yorshire. Im a bit confused now, please help me out. I have it that the y-speed values reported by Phontomhelp is along y-axis (North/South, latitudinal axis) ? and so is the x-speed the speed along x-axis (East/West, longitudinal axis) ?

Then I also want to ask: The log file report 2 values for each of these (X, Y, & Z) entries. It is for example OSD.ySpeed [MPH] & OSD.ySpeedMax [MPH]. I noticed that the yspeed (or X- & Z- speed) does have positive and negative values, but the SpeedMax only records the positive values, and does keep increasing as the positive values increase (not the negative values). Can you help me to clear this up please

Many thanks

 

[Yorkshire_Pud]

Hi Yorshire. Im a bit confused now, please help me out. I have it that the y-speed values reported by Phontomhelp is along y-axis (North/South, latitudinal axis) ? and so is the x-speed the speed along x-axis (East/West, longitudinal axis) ?

Then I also want to ask: The log file report 2 values for each of these (X, Y, & Z) entries. It is for example OSD.ySpeed [MPH] & OSD.ySpeedMax [MPH]. I noticed that the yspeed (or X- & Z- speed) does have positive and negative values, but the SpeedMax only records the positive values, and does keep increasing as the positive values increase (not the negative values). Can you help me to clear this up please

Many thanks

I will have to get onto computer to have a look. But off the top of my head it may be that SpeedMax displays only the maximum magnitude of the speed and magnitude is given as a sign less quantity.

If you want to draw someone's attention to something your best bet is to either reply to a post of theirs or enter their full 'handle' but with "@" immediately preceding their handle. They then get a notification of the post.
I only saw your post by chance

 

[riterb97]

Thanks a lot for the advice. I'm not very familiar with forums (Handle?). Is this how I should rather reply then?

@Yorkshire_Pud​

 

[Yorkshire_Pud]

Thanks a lot for the advice. I'm not very familiar with forums (Handle?). Is this how I should rather reply then?

@Yorkshire_Pud​

If replying to a post then I would you the reply button which is to be found to the extreme right below the post's window.
If not replying to post of theirs but 'mentioning' them then use the "@" approach

 

[Yorkshire_Pud]

Then I also want to ask: The log file report 2 values for each of these (X, Y, & Z) entries. It is for example OSD.ySpeed [MPH] & OSD.ySpeedMax [MPH]. I noticed that the yspeed (or X- & Z- speed) does have positive and negative values, but the SpeedMax only records the positive values, and does keep increasing as the positive values increase (not the negative values). Can you help me to clear this up please

Ahh, I see what you mean.
This is a question for @msinger / @BudWalker I think.

 

[BudWalker]

I have it that the y-speed values reported by Phontomhelp is along y-axis (North/South, latitudinal axis) ? and so is the x-speed the speed along x-axis (East/West, longitudinal axis) ?
..............

I believe that's reversed. ySpeed is along East/West (longitudinal) axis. And xSpeed is along North/South (latitudinal) axis

 

[slup]

@Yorkshire_Pud and @riterb97

If looking into a .txt log from an older DJI drone with unencrypted logs (neither Airdata or PhantomHelp is needed to decrypt it)... the OSD:xyzSpeedMax doesn't exist, it just contain OSD:xyzSpeed. It's similar if looking into the CSV from Airdata, no OSD:xyzSpeedMax exist. It's just from the PhantomHelp CSV you get a OSD:xyzSpeedMax.

This leads me to think that this data field is a calculation in the PhantomHelp log viewer... & that the author just considered MAX (here meaning positive), & not MIN (as in max negative).

 

[Yorkshire_Pud]

@Yorkshire_Pud and @riterb97

If looking into a .txt log from an older DJI drone with unencrypted logs (neither Airdata or PhantomHelp is needed to decrypt it)... the OSD:xyzSpeedMax doesn't exist, it just contain OSD:xyzSpeed. It's similar if looking into the CSV from Airdata, no OSD:xyzSpeedMax exist. It's just from the PhantomHelp CSV you get a OSD:xyzSpeedMax.

This leads me to think that this data field is a calculation in the PhantomHelp log viewer... & that the author just considered MAX (here meaning positive), & not MIN (as in max negative).

Thanks, I will have a look at my Go and Go4 logs at some point.

Doesn't or didn't Msinger mark calculated value in some way, I'm pretty certain he did early on but haven't checked 'recently'.

There are quite a few differences between the CSVs of FLY and Go/Go4.