compass error over water

xrider · Dec 15, 2020

hello pilots

a friend of mine was flyin his p3p over water when suddently a compass error occured.. im givin you the .dat as we dont know what happened over there.. need your help to shed some light of what happened..

FLY714 (2020_11_10 18_23_16 UTC).DAT

drive.google.com

thanks a lot
xrider

cheddarman · Dec 15, 2020

It could be something to do with the fact that water doesn't have much contrast and the drone can get confused about altitude and movement?
Just a thought.

xrider · Dec 15, 2020

cheddarman said:
It could be something to do with the fact that water doesn't have much contrast and the drone can get confused about altitude and movement?
Just a thought.

no.. thats about vps.. he was flyin about 30m above the water.. vps works till 3m on phantom 3s..
im thinking about ship interference or somekind of emi.. really dont know.. but that was too mutch.. even if i had faced compass errors midflight in the past i have never seen something like this before..

Meta4 · Dec 15, 2020

cheddarman said:
It could be something to do with the fact that water doesn't have much contrast and the drone can get confused about altitude and movement?
Just a thought.

VPS has nothing to do with the compass

Meta4 · Dec 15, 2020

xrider said:
im thinking about ship interference or somekind of emi.. really dont know.. but that was too mutch.. even if i had faced compass errors midflight in the past i have never seen something like this before..

He would have to be only a few feet away from landing on a ship for it to have any effect on his drone's compass and there's no kind or EMI that would have done anything.
If you post his .txt file I'll have a look

xrider · Dec 16, 2020

Meta4 said:
He would have to be only a few feet away from landing on a ship for it to have any effect on his drone's compass and there's no kind or EMI that would have done anything.
If you post his .txt file I'll have a look

okay.. i dont have the .txt but i have the .dat ..if you see there is a huge "compass error large" midflight..

FLY714 (2020_11_10 18_23_16 UTC).DAT

drive.google.com

Meta4 · Dec 16, 2020

xrider said:
okay.. i dont have the .txt but i have the .dat ..if you see there is a huge "compass error large" midflight..

Sorry ... I wanted the .txt file
If you can get it, I'll look at it

cheddarman · Dec 16, 2020

Surely there is more data in the .DAT file than the .Txt?
Xrider, the .Txt file is stored on the device you were using to fly the drone, iPad, mobile phone etc. whatever?

Meta4 · Dec 16, 2020

cheddarman said:
Surely there is more data in the .DAT file than the .Txt?

I don't want more data, I want the .txt file.

cheddarman said:
Xrider, the .Txt file is stored on the device you were using to fly the drone, iPad, mobile phone etc. whatever?

It was his friend's drone flight

xrider · Dec 16, 2020

meta my friend has no longer the tablet anymore.. .txt file was in it.. he gave me his drone for troubleshooting so.. i really wanna know what happened to proceed with a fix.. if someone can read the .dat file and tell me if its got sth faulty i surely would be grateful.

till now the only thing that i see are warnings about the compass.. we stay far away.. you know.. covid.. so im all alone tryin to understand what has cause the error before sendin it back to the sky..

Meta4 · Dec 16, 2020

xrider said:
meta my friend has no longer the tablet anymore.. .txt file was in it..

Can you give a more detailed description of the incident?

cheddarman · Dec 16, 2020

So how long ago was this incident and as Meta4 says, exactly what happened? Did the drone end up in the water, did it come home safely?

xrider · Dec 16, 2020

@Meta4 he just changed tablet givin a format to the old one before givin it to his son for e-classes..

@cheddarman i see he had pressed rth button so.. i guess drone went back.. or autolanded because of the sudden compass error.. really dont know.. he gave me the drone to fix the issue.. but i really dont know from where to begin.. he told me that a sudden compass error showed up while flyin over water.. as i saw on event stream.. he had pressed the rth button.. as i saw on the event stream as well.. but i really cant understand the cause.. everything seem normal at the startup.. i cant see any message coming from the compass showin that it was sitting close to sth metallic.. but message showed up mid flight.. dont know what to guess.. ive asked for the .txt and the log wasnt available anymore as the tablet whitch was used for flights had been formated..

anyway.. ive started up the drone.. downloaded the last .dat when all this weird compass errors took place.. and the safest thing to do before i proceed to any kind of fix or test flight is to examine what was the cause of the compass error.. i surely dont wanna crash it if it starts behaving erratically..

Capt KO · Dec 16, 2020

After your compass calibration, are you getting any error messages? May be worth a short flight to see if you can duplicate so that you will have the correct files to post. Be prepared to land asap. Low and slow.
Good luck.

xrider · Dec 16, 2020

okay.. i think we ve got another problem here.. thats why i really need your help before im gonna give any kind of test flight..

is there anyone who can read .dat logs and can give me an idea of what has happened and shed some light in this case??

@sar104 ?? @Fly Dawg ?? anyone?? please??

Meta4 · Dec 16, 2020

xrider said:
@cheddarman i see he had pressed rth button so.. i guess drone went back.. or autolanded because of the sudden compass error.. really dont know..

Sorry but it's going to be very hard to work out what the problem might be because we know next to nothing about the incident.
Not enough to make an educated guess.
It's not normal to get a compass error, mid-flight and it might have been assocoated with a yaw error.
Or maybe not ... without a detailed description of the incident and/or data, it's just a mystery.

xrider · Dec 16, 2020

Meta4 said:
Sorry but it's going to be very hard to work out what the problem might be because we know next to nothing about the incident.
Not enough to make an educated guess.
It's not normal to get a compass error, mid-flight and it might have been assocoated with a yaw error.
Or maybe not ... without a detailed description of the incident and/or data, it's just a mystery.

ive already gave you a .dat.. so much information there.. ive seen the error but i dont know the sudden cause of it as im not sutch an expert like so many of you of reading logs.. the only i can give you are .dats
i can provide you the previous log.. fly713 if its hard to determine the cause..

Meta4 · Dec 16, 2020

xrider said:
ive already gave you a .dat.. so much information there.. ive seen the error but i dont know the sudden cause of it as im not sutch an expert like so many of you of reading logs.. the only i can give you are .dats
i can provide you the previous log.. fly713 if its hard to determine the cause..

That's fine, but I don't do dat files.
And without even a basic description of what actually happened, there's nothing I can tell about the drone or even if it has a problem.

cheddarman · Dec 17, 2020

Im no expert but from the .DAT file, not a very long flight by the looks of it and an "unusual" throttle (purple) adjustment at ½ and 4 minutes. Is that when you had the compassions error, you closed the throttle?

I can plot any of the parameters that might help, this is just the RC controls.

cheddarman · Dec 17, 2020

Xrider - was the fight just over 5 minutes (am I reading the data correctly). This is the compass plot, can't see anything significant there?? Bit of a glitch about 1½ BEFORE lift off. Maybe someone more experienced can read more into it.