Found a very strange flight record in my DJI Fly and Airdata...

[Ronny St.]

Yesterday I installed Airdata UAV to get access to more details of my flights. One flight struck my attention and I checked it immediately on my phone, but it is wrong there also.
For some reason the maximum distance of that flight is recorded as being 502 m in my phone and 565 m on Airdata. I don't understand why this is different since Airdata should take the data from the phone. But, anyway, what's worse is that the home point is also completely wrong, I never took off there nor have I been flying there.
It ruins the statistics of the flights of course, and that kind of annoys me.

Here is the supposed flightplan (taken from Airdata):


The fuzzle in the lower part is the actual flight plan as seen in the zoom in picture:


I only made flights directly around my home so how on earth did it produce that yellow line going to the upper part in the picture? It looks like it 'shoots' away suddenly without return... And how come it put the home point in the completely wrong location?

In my smartphone I 'replayed' the flight and it never got to the point far from my home.

Does someone has any idea what could have happened so that I can prevent that in the future? As for now, the statistics are wrong and I will probably have no way to 'repair' them, or can I?

Thanks for replying!

Edit: just noticed that the date is wrong also. In my smartphone it is recorded on the 30th of April, and in Airdata it is on the 26th of April... It is getting stranger and stranger now.

 

[msinger]

Do you see the same thing when you upload it here?

 

[Ronny St.]

Thanks for responding, MavicHelp. It is a great link that I did not know of yet.
I must admit I am new to browsing through the DJI files in my smartphone, but I found the directory with the logs. But yes, I see it there also on the 26th of april. The link is DJI Flight Log Viewer - PhantomHelp.com. And if I 'replay' the flight there, at no point the path to the north is followed. Could it be some strange artifact in the log? If so, I still wonder why it is on the wrong date in Airdata and what I can do to prevent this in the future.

 

[Meta4]

If so, I still wonder why it is on the wrong date in Airdata and what I can do to prevent this in the future.

You launched at 0:07.4 without waiting for GPS and started flying forwards at 0:15.7, still without GPS.
Your GPS receiver was starting to get GPS position data at 0:20.5 but the location fix was recognised by the flight controller as only approximate but this is recorded in data and the straight line you commented on is from the point where GPS data started.
At 0:21.7 the flight controller was satisfied that GPS data was now good enough and recorded a home point at 0:22.2.

So what you are seeing is a little "fake" data before the GPS was able to produce an accurate position fix.
You can avoid this by waiting for GPS before launching.
That has the added benefit of recording a home point where you launch rather than somewhere off in the distance.

 

[Ronny St.]

Ah, ok, so that is the reason! Thanks for interpreting the data. Very interesting to learn from. But I wonder where did you e.g. the 0:07.4 and the other time data that you are mentioning? I only see the following data in the first colums (took only a screenshot of a part of it as an example) :



As far as I can see, the MM was at 0m20.7s at the phantom home point and at 0m20.8s it is halfway back to the real position. At 0m20.9 it seems to right.

At 0:21.7 the flight controller was satisfied that GPS data was now good enough and recorded a home point at 0:22.2.

Sorry, but I cannot see that in the data. Can you please explain me so that I know how to interprete those data in the future? I am always keen on learning something
I see also from 2m6.3s that the flight mode changed from P-GPS to tripod and I do not what that means. For me a tripod is like a standard on which you can put your photo equipment on...

Conclusion: I will wait from now on till I have enough satellites for good positioning before take-off.

Only remains the question why these data are not found as such in Airdata UAV at the right day. I wonder if it it possible to delete all my flights in Airdata and upload them again without them being archived so that I already would pass the 100 flights limit of the free version. If I know that the data are transferred correctly I would gladly pay for Airdata, but I first want to be sure I can rely on it.

Thank you for your help!

Greetings from Belgium,

Ronny

Edit: I suppose I cannot correct this in the logs manually? It would be nice to have no false flight data in my logs ?

 

[Meta4]

Very interesting to learn from. But I wonder where did you e.g. the 0:07.4 and the other time data that you are mentioning?

Sorry, but I cannot see that in the data. Can you please explain me so that I know how to interpret those data in the future? I am always keen on learning something

You are only loking at the brief summary of the data on the first screen.
I went deeper into the data to see the fine details.
You do that by clicking on the Download CSV link under the aerial image

I see also from 2m6.3s that the flight mode changed from P-GPS to tripod and I do not what that means. For me a tripod is like a standard on which you can put your photo equipment on...

Tripod Mode is confusingly named.
It slows down the maximum speed and the joystick sensitivity.
It is useful for slow flying in close to obstacles etc.

 

[Ronny St.]

Thanks again for responding, Meta4! It would be nice to have a macro or something in exel to put the data in columns since that exel file seems to have even more detailed information. I now did it manually but it would be a lot handier to have something that loads a .csv automatically in column form.
The name 'tripod' is now clear to me, it is indeed confusing named. What does the tripod mode trigger to kick in? I suppose it is when the MM with his bottom obstacle detection sees the ground coming close, since it has no other obstacle detectors?