The other day I was taking some video of a new ball field close to the house.  I had my P4 somewhat low to the ground (The log indicates I was about 18 ft. but I thought I was a little lower) and was trying to get a smooth "running the bases" look.   On one pass I was almost to 2nd base and I get the following errors:

Ultrasonic Systems Error. Land Immediately; Satellite positioning off. Fly with Caution.


I immediately switched to ATTI mode and lifted the craft out of the park and over to a safe landing area.  Before I landed, I placed the P4 back into full Phantom mode
and everything seemed to work without any issue.  I have had 4-5 flights since then without issue including some low to the ground flights.


It appears to be an isolated incident but I would like to have feedback as to possible causes.  It seems like I was kicking up some dust so I wonder if the dust particles in the
air could have diffused the sound waves creating errors with the return echo.


Here is my log:

http://www.phantomhelp.com/logviewer/2ZR9YSZUXAKYXHJLI78D/#


The error was received at 15m 12.9s


CP

Hello CP, what're the drone' s firmware version and the app version? Does it happen again?

DJI-Paladin:

The firmware is the latest v1.1.411 and I am running version 2.81 ANDROID version of the DJI-Go App.
I performed IMU Calibration after firmware update and then compass calibration on location in the middle of a grass field far away from any metal.  

I have had about 4 or 5 flights since then with some low altitude flight and haven't seen the issue come up again.  

CrimsonPhantom Posted at 2016-6-15 18:47
DJI-Paladin:

The firmware is the latest v1.1.411 and I am running version 2.81 ANDROID version of t ...

What kind of mobile device do you use ? Could you post a screenshot of this issue？ If it is convenient，please sync the flight record via DJI Go app and leave your DJI account here.I'll try to look into it.

DJI-Paladin Posted at 2016-6-15 21:31
What kind of mobile device do you use ? Could you post a screenshot of this issue？ If it is conve ...

Paladin,

I use an nvidia shield K1.  Attached is a screenshot from the video playback.  However, the Ultrasonic Systems Error notification does not pop up, only the Satellite positioning off warning.
The log is also uploaded here:

http://www.phantomhelp.com/logviewer/2ZR9YSZUXAKYXHJLI78D/#


And it does contain the Ultrasonic Systems Error (So I know I didn't imagine it

The flight where I received the error is dated 12JUN2016 Mileage:  7401.9 ft, time:  17min
The warning was received at:  15m 12.9s

my dji account id is bdphillips@cableone.net.

Let me know if you need anything else.

CrimsonPhantom Posted at 2016-6-16 18:38
Paladin,

I use an nvidia shield K1.  Attached is a screenshot from the video playback.  However, t ...

Thanks for your response , CP. I've synced and checked your flight record and this error is there at that moment. I'd suggest you to download the flight data (.DAT files ) of that time from the drone via DJI Assistant 2. Both of the FC data and vision module data are necessary.Then upload to dropbox and post the public link here. We will look into your case. Besides, did you install a gimbal protector at that time?

DJI-Paladin Posted at 2016-6-17 22:40
Thanks for your response , CP. I've synced and checked your flight record and this error is there  ...

Paladin,

There was no vision module data present for that particular day.  Matter of fact, out of 18 entries, there are only 5 with a vision module file.  Is that normal????? The FC data has been downloaded and you can grab it using this link:

https://www.dropbox.com/home/DJI%20Flight%20Data%20Review
There was NO gimbal protector installed so there were no obstruction.  However, I was flying low over a baseball field down the running lines.  As I was flying I noticed the wind from the phantom was creating a large amount of dust.  I'm thinking that the dust created a lot of different echo returns as sound was being reflected by the dust cloud...  this may have been the cause of the error.  I've had a number of flights since then and there have been no errors.  But I would appreciate you looking at the data and giving me your opinion.




CP

CrimsonPhantom Posted at 2016-6-18 20:25
Paladin,

There was no vision module data present for that particular day.  Matter of fact, out of  ...

I'll try to pass your case to our Data analysis team in the business hours.

DJI-Paladin Posted at 2016-6-18 21:56
I'll try to pass your case to our Data analysis team in the business hours.

Hey Paladin,

Any update on this?  

Also, I asked a question about whether or not it was normal to have flight entries without the vision module file...  Is that typical?

CrimsonPhantom Posted at 2016-6-22 05:23
Hey Paladin,

Any update on this?  

I'm sorry to say that when I try to download your data again, the link doesn't work. Could you try to set it to public again?

CrimsonPhantom Posted at 2016-6-22 05:23
Hey Paladin,

Any update on this?  

I've confirmed this vision file issue with our developers.It is normal.

DJI-Paladin Posted at 2016-6-21 21:02
I've confirmed this vision file issue with our developers.It is normal.

Thanks!!  I appreciate it.

DJI-Paladin Posted at 2016-6-21 20:46
I'm sorry to say that when I try to download your data again, the link doesn't work. Could you try ...

Sorry...  This is the link that dropbox gives me for public access... try this one.

https://www.dropbox.com/sh/3j8yqnev8zif6lg/AAC6lcIRks-xSlA2YnGB1IX7a?dl=0

CrimsonPhantom Posted at 2016-6-22 11:31
Sorry...  This is the link that dropbox gives me for public access... try this one.

https://www.dr ...

OK I'll try.

Thank you for your patience. In the data analysis, there is nothing wrong with your drone. So don't worry about that. We will do our best to improve our products.

DJI-Paladin Posted at 2016-6-24 05:50
Thank you for your patience. In the data analysis, there is nothing wrong with your drone. So don't  ...

Thanks Paladin...  I really didn't think I had any issues.  My Phantom has been absolutely perfect since day 1.

I really think the dust cloud that was kicked up by my Phantom created a chaffing effect and confused the sonar...  

Again, thanks for looking into it!!