My first near flyaway --> CSV Analysis added with intereresting discoveries!

[Ferdi]

Had flown it 4 other times that day in same area and I always check the MOD value. All were OK. Interestingly, it got the Compass warning while it was 100ft high in the air. Why would it go wrong then?

I don't know, but most likely something was having an effect on the compass while on the ground, showing normal compass readings. Then 100ft in the air, that effect no longer had an impact on the compass. I had a fly away with the Inspire1 where after 5 mins of perfect flying and more than 250m from take-off spot it went nuts, flying at full speed away from the our pilot until he switched to atti.

Did you see any "toilet bowl effect", where it drifts in circles that get bigger and bigger?

 

[Justgregg]

I think 30 miles is on the short side for a real *need* to recalibrate the compass. But honestly, I'm not sure. It can't hurt to calibrate the compass if in doubt.

Im soo in that habit of re calibrating with my other ships and havnt had any issues, so I guess I will keep doing it.

 

[Foosy]

I don't know, but most likely something was having an effect on the compass while on the ground, showing normal compass readings. Then 100ft in the air, that effect no longer had an impact on the compass. I had a fly away with the Inspire1 where after 5 mins of perfect flying and more than 250m from take-off spot it went nuts, flying at full speed away from the our pilot until he switched to atti.

Did you see any "toilet bowl effect", where it drifts in circles that get bigger and bigger?

No, no toilet bowl effect. Also interestingly when I regained control and landed it, I am pretty sure the compass error had gone - so it was an error only during the flight. It also flew quite a long flight without any issues 10 minutes before this flight, less than a mile away from this spot where the trouble occurred. Another crazy idea - maybe there is something in the church's spire that whacked the compass ?!?!?

 

[Ferdi]

Now is it true that the inspire and the phantom 3 do not need compass calibration all the time. I was flying another airframe with naza v2 and dji was wanting you to re callibrate if you travelled over like 100 miles. I travel up to 30 miles between photo shoots as I film farm properties, should I be re calibrating after re locating?

My opinion (gathered from the smart guys over on the Inspire Forum) is that the more you calibrate, the better chance you have of getting a bad calibration.

Find a place where there are no interference of any sort, calibrate there, shut down bird, then move 20m in any direction, restart the bird, check mods, shut down bird, move 20m in another direction, restart bird, check mods. If if the mods are all good, don't recalibrate unless you're moving more than 300km.
Always check mods before flying. If mods are out don't immediately recalibrate. Turn off bird, move 20m in any direction (as far away from interference as possible), restart bird and check mods. If they are fine, don't calibrate. If not, find a safe spot to redo calibration.

 

[Foosy]

Im soo in that habit of re calibrating with my other ships and havnt had any issues, so I guess I will keep doing it.

If you calibrate too much you can increase your risk of miscalibration. I read here that it is more important to check the MOD value which needs to be between 1400 and 1600. I do recalibrate if I go on trips further than 100 miles from previous location it was flown.

 

[Ferdi]

No, no toilet bowl effect. Also interestingly when I regained control and landed it, I am pretty sure the compass error had gone - so it was an error only during the flight. It also flew quite a long flight without any issues 10 minutes before this flight, less than a mile away from this spot where the trouble occurred. Another crazy idea - maybe there is something in the church's spire that whacked the compass ?!?!?

Very likely got a lot of metal in there, although you'd have to be fairly close for it to have an effect. Sometimes these things just have a "brain-fart". No real way to avoid a fly away completely, but the best bet is to turn "Multiple Flight Mode" on, and next time she misbehaves, switch to Atti and bring her naughty *** home

 

[Justgregg]

Thanks,,speaking of mods, I never am able to hit around 1500. always from 1380 to around 1450. Am I within the parameters?

 

[Ferdi]

Thanks,,speaking of mods, I never am able to hit around 1500. always from 1380 to around 1450. Am I within the parameters?

1400-1600 are good. Think 1380 is a bit low

 

[kdrak]

well something blocked your GPS reception.

Every time I go for a flight I always stay at least a minute at low altitude i.e. 2 or 3meters and observing the behaviour of P3 while not giving any stick input. In case that there is a problem with compass or GPS I will detect some drifting behaviour so I bring it down for calibration or any other action required

 

[ScottyT]

This is interesting, although I must admit, I am still not grasping what exactly happened.
By the way, I did upload the DAT file to http://www.djilogs.com/, and it created a log file which has a bunch of commands that I do not know yet how to interpret. Any pointers or should I use a different program?

Yeah I've experienced the same - doesn't seem to convert the DAT files correctly. Try grabbing the TXT log file off your tablet and converting that instead.

 

[Foosy]

Yeah I've experienced the same - doesn't seem to convert the DAT files correctly. Try grabbing the TXT log file off your tablet and converting that instead.

OK, I just did that...
The csv file generated shows that there were 15 satellites when I got the warning message. Most of the flight was between 14 and 15, with 10 satellites at the landing for a brief moment. Hard for me to believe it lost GPS signal. Also, if compass is not calibrated, it should lose its direction, but not fly away -> at least theoretically. I will upload CSV....

 

[Ferdi]

OK, I just did that...
The csv file generated shows that there were 15 satellites when I got the warning message. Most of the flight was between 14 and 15, with 10 satellites at the landing for a brief moment. Hard for me to believe it lost GPS signal. Also, if compass is not calibrated, it should lose its direction, but not fly away -> at least theoretically. I will upload CSV....

As far as I understand it (and my understanding is limited by what I've read on the Inspire forum posted by some very knowledgable gents), if the compass is out of wack it conflicts with the GPS, they start fighting, about which way is north/south/east/west, and the bird starts behaving crazy. Don't know why it just flies off with no input from the user, but that's what happens time and again. I've seen it so many times on the Inspire forum (was another one posted just today). Switching to Atti effectively takes the GPS out of the equation, so the conflict ceases, and you are able to bring your beloved bird back home.

 

[Foosy]

I have attached the the CSV, zipped.
And here is my analysis:

I note the following interesting items, provided we can trust the log file:
1. There is no compass error - even though the app alerted me there was....
2. The bird switches to using VISION at the time 00:29.5 until 01:02.5 ?!?!?!!!
3. For the same period as above the unit gets a YAW_ERROR_LARGE for nonGPScause
4. Don't know what it means, but throughout the flight imuInitFailReason is set to MonitorError, but imuInitFailReason.raw is 0, so does not seem like a problem

Does it look like the vision positioning system is the thing that screwed my bird?
Does it look like the compass error messages and warnings we get ARE NOT really compass errors?
Are we on to something?

PS>
The csv has a minor issue where the warning messages are split and cause the data to shift by a cell.

 

[Ferdi]

I have attached the the CSV, zipped.
And here is my analysis:

I note the following interesting items, provided we can trust the log file:
1. There is no compass error - even though the app alerted me there was....
2. The bird switches to using VISION at the time 00:29.5 until 01:02.5 ?!?!?!!!
3. For the same period as above the unit gets a YAW_ERROR_LARGE for nonGPScause
4. Don't know what it means, but throughout the flight imuInitFailReason is set to MonitorError, but imuInitFailReason.raw is 0, so does not seem like a problem

Does it look like the vision positioning system is the thing that screwed my bird?
Does it look like the compass error messages and warnings we get ARE NOT really compass errors?
Are we on to something?

PS>
The csv has a minor issue where the warning messages are split and cause the data to shift by a cell.

Interesting... I've heard that the VPS can cause problems on the P3, so I've never had it turned on. Always wished I could turn it off on the Inspire1 too.
Since there was no toilet bowling before going loopy, you might be correct in the assumption that it wasn't compass related.

 

[Ken Pascoe]

Flyaways are NOT fun. I suspect this one came about because of the following series of events. I took the P3 out front of the house and commenced power on. Then I powered up the controller/app and saw that I had left the memory card in my computer. Not wanting to leave the drone out front, I moved it to the porch during alignment, then went and got the memory card. I switched the P3 off, inserted the memory card, moved the P3 back to the driveway and powered on. The power up cycle was VERY quick, but I didn't think anything of it. Then I launched, and found I had a bucking bronco in the air. I suspect if I'd had the presence of mind to switch to ATT I would have had better control. Instead I fought it in P-GPS back to the ground, without damage fortunately. Several lessons learnt!

 

[Foosy]

What happened to you @Ken Pascoe , looks like a toilet bowl effect. In any case, I would recommend to view your txt file and analyze it, but please don't hijack this thread.

I think I ran into a problem, that if we are able to verify, would indicate an issue with the p3p algorithm that responds to sensors.
Back to my case: what causes a YAW_ERROR_LARGE?

I

 

[Foosy]

I know there are a few people from DJI monitoring those threads.
Can anyone look at the logs and voice an opinion as what is the next step?
I had opened a case with DJI regarding another issue - and had not received any response, which is why I was hoping to get more traction here.

I definitely think that the issue I experienced should be addressed, even if by a simple fix to put in the firmware a condition that if height>10ft then not switch to vision mode.

 

[damitjim01]

Is there power lines on poles along that street? Possible EMF screwing with the compass?

 

[yblaser]

Foosy, I had a similar experience a couple of weeks ago. I flew a full battery with no issues. Put the second battery in, and was flying in the same area at about 250 ft when I got a compass error message displayed on the app and the P3 went into P-vision mode. At the time I was in the settings menu about to correct the horizon tilt, by the time I backed out of the menu and started to try to fly back home it returned to P-GPS mode. I haven't had a problem since in the six or so flights I've done.

 

[Foosy]

Is there power lines on poles along that street? Possible EMF screwing with the compass?

If it is screwing up the compass, why is there no such indication in the logs?
Look at what I found in the logs for the flight: something else is going on....