Ultrasonic Systems Error

[sar104]

...

With all the respect to others who have gone to great technical length ... I still feel that the only people who can really say what is wrong are DJI themselves or third party repair services who have the means to connect directly to your machine and do full diagnostics. I do not believe that DJI have programmed for ALL info to be available via dat files and logs that we can look at.

...

Nigel

That was also my final point in my previous post, but I don’t think it’s a reason not to figure it out. Additionally, DJI themselves have a mixed history of diagnosing flight problems. I have no doubt that they have the tools and knowledge, but I don’t think they generally use them for individual cases.

 

[Sir Nobby]

@BudWalker Just for the heck of it, here is the GE profile. Notice the First RTH. The OP was already heading back before that occured.

View attachment 96012

Hi @Fly Dawg, this is probably of no interest seeing as this thread is a couple of weeks old but I still can't get the video to marry up with the data...
@solentlife have you any ideas?
Can you see what I mean about the video not matching?
Any ideas?

 

[sar104]

Hi @Fly Dawg, this is probably of no interest seeing as this thread is a couple of weeks old but I still can't get the video to marry up with the data...
@solentlife have you any ideas?
Can you see what I mean about the video not matching?
Any ideas?View attachment 96422

Which data are you concerned about it not matching? If you mean the GPS location data then that's not surprise at all, because it stopped receiving fresh data.

 

[Elbert Hill]

I mentioned that earlier in this thread, about the fact that I was over the country club, and not of my own accord, fighting the craft to get it back on the path to home. However,Bud discounted that fact, saying it only "appeared" that I was over the country club. But I didn't want to argue the point because at that time some folks on this string was thinking I was out of my mind. But I think as time went on and the data was reviewed I think that view has changed somewhat.

So, thanks for validating that statement I made about that, and other events I related about in this string early on.

I just replaced the GPS Module a few days ago, took it out and everything seemed to be ok. But I'm going to be hyper alert while flying this particular aircraft for some time to come, just in case there is something else lurking in the shadows.

Again, thanks to everyone who has taken the time to analyse the data from this ill fated flight and share it here.

Much appreciated !

 

[Fly Dawg]

But I didn't want to argue the point because at that time some folks on this string was thinking I was out of my mind.

I don't think that is true. The only thing that I could see that would have made you feel that way, would be considering the fact that the first RTH should have been left alone to complete. That said, everyone here want's to assist other flyers as best they can. Right, Wrong or indifferent. And I appreciate the fact of recognizing those who looked in to your issue. Carry on.....Fly safe!

 

[Sir Nobby]

I mentioned that earlier in this thread, about the fact that I was over the country club, and not of my own accord, fighting the craft to get it back on the path to home. However,Bud discounted that fact, saying it only "appeared" that I was over the country club. But I didn't want to argue the point because at that time some folks on this string was thinking I was out of my mind. But I think as time went on and the data was reviewed I think that view has changed somewhat.

So, thanks for validating that statement I made about that, and other events I related about in this string early on.

I just replaced the GPS Module a few days ago, took it out and everything seemed to be ok. But I'm going to be hyper alert while flying this particular aircraft for some time to come, just in case there is something else lurking in the shadows.

Again, thanks to everyone who has taken the time to analyse the data from this ill fated flight and share it here.

Much appreciated !

Hi, glad you've got things resolved and now it will take time to build your confidence back up again.

 

[Sir Nobby]

Which data are you concerned about it not matching? If you mean the GPS location data then that's not surprise at all, because it stopped receiving fresh data.

I guess so, thanks for clarifying it for me. Sorry if I've gone too deep into this but it's just me.

 

[BudWalker]

OK, for you trig fans. Here is the frame from the video where the P3 was the furthest east. That's at about 13:11 in the video and 733 secs form the log. The vertical FOV of the P3 camera is 66°. From the horizon to the building labelled with the blue A is 58% of the vertical span in this frame. That means the building is 38° below the horizon

Now looking at the profile we have

The height of the P3 was 144m. So the tangent(38°) = 114 m/ distance to the building marked with the A symbol. Doing the trig gives the distance of 146m to that building.

Finally, using the Google Earth ruler and places the P3 at the yellow thumbtack.

Which is very close to the position in the log

 

[Sir Nobby]

OK, for you trig fans. Here is the frame from the video where the P3 was the furthest east. That's at about 13:11 in the video and 733 secs form the log. The vertical FOV of the P3 camera is 66°. From the horizon to the building labelled with the blue A is 58% of the vertical span in this frame. That means the building is 38° below the horizon
View attachment 96431

Now looking at the profile we have
View attachment 96432
The height of the P3 was 144m. So the tangent(38°) = 114 m/ distance to the building marked with the A symbol. Doing the trig gives the distance of 146m to that building.

Finally, using the Google Earth ruler and places the P3 at the yellow thumbtack.
View attachment 96433

Which is very close to the position in the log
View attachment 96434

Blimey! You're really getting into this, aren't you! My screenshot from the gentleman's video (1) is at 15:29 so I think I'm probably further along the data stream

 

[BudWalker]

Well, I must say that was some pretty impressive analysis on my part. Unfortunately it isn't relevant since there was more to the video after this. I had taken the description that @Elbert Hill gave in post #34 "If you'l follow the video link, move forward to about 13 min" and used that without looking at the rest of the video.

Sorry about this. The video definitely shows the P3 being way over the country club

 

[sar104]

Well, I must say that was some pretty impressive analysis on my part. Unfortunately it isn't relevant since there was more to the video after this. I had taken the description that @Elbert Hill gave in post #34 "If you'l follow the video link, move forward to about 13 min" and used that without looking at the rest of the video.

Sorry about this. The video definitely shows the P3 being way over the country club

It's not surprising that it drifted since it had absolutely no clue where it was due to the frozen data stream from the GPS. I'm still puzzled by the impossible IMU data though.

 

[Sir Nobby]

Well, I must say that was some pretty impressive analysis on my part. Unfortunately it isn't relevant since there was more to the video after this. I had taken the description that @Elbert Hill gave in post #34 "If you'l follow the video link, move forward to about 13 min" and used that without looking at the rest of the video.

Sorry about this. The video definitely shows the P3 being way over the country club

@BudWalker, easy mistake to make, I sat and watched the whole video (several times) and was so taken in by the beautiful sunrise that I was willing the bird to make it home in one piece! I'm in awe of how you guys interpret the data as it looks like an awfully big Excel spreadsheet to me