Atti and speed error

[kevinp3s]

Hi All

When looking @ my logs of my flight I notice that it goes into ATTI mode with a speed error ... what would cause that ? It did a "flyaway" to towards some trees so I did a "forced landing " lucky it was not to high . Also on Auto Takeoff I see that I get a negative value for Altitude . Attached is the log file

 

[With The Birds]

Upload your flight log to DJI Flight Log Viewer or Airdata UAV - Flight Data Analysis for Drones and paste a link to the flight back in the thread.

 

[Meta4]

When looking @ my logs of my flight I notice that it goes into ATTI mode with a speed error ... what would cause that ?

Here's your flight record: DJI Flight Log Viewer - PhantomHelp.com
At 6:41.3, when the error messages start, the flight data shows the following speeds (in mph) for each subsequent 0.1 second.
3.2 7.4 30 29.3 21.4 10 19.9 10.4 3.7 10.4 11.6 7.9 12 2.1
Clearly the speed cannot be jumping around like that and since the speed comes from GPS, the flight controller has worked out that the GPS data is wrong.
The Phantom can fly without GPS but can't handle a conflict between GPS and compass.
So it ignores the GPS data and your Phantom finds itself in atti mode.
The speed error message is showing that the flight controller has identified the speed data as incorrect.

It did a "flyaway" to towards some trees so I did a "forced landing " lucky it was not to high

Can you explain what you observed that you are describing as flying away?

 

[kevinp3s]

yep it moved swiftly (accelerated) from its hover position to my left towards some trees ... my reaction was to land it as quck as possible before I lost control.and a ground landing might be better than hitting trees...there was a slight wind. sorry I tried to load the csv file from the phantomhelp page but it failed....but I see I should have posted the link......thanks for the help .....why would there be conflict between the gps and compass

 

[With The Birds]

yep it moved swiftly (accelerated) from its hover position to my left towards some trees ... my reaction was to land it as quck as possible before I lost control.and a ground landing might be better than hitting trees...there was a slight wind. sorry I tried to load the csv file from the phantomhelp page but it failed....but I see I should have posted the link......thanks for the help .....why would there be conflict between the gps and compass

You need to fly the AC atti mide, it won’t hold position- it will drift until it meets with an obstacle or land when the battery reaches critical level.

 

[kevinp3s]

okay ..but unfortunately it changed to atti mode automatically and suddenly..I was hovering and taking a pic and then going to land .....as it was a few meters from me I didnt expect it to lose gps ...was on open farmland ...no wifi interference

 

[Meta4]

why would there be conflict between the gps and compass

Because the GPS was giving false data - see the speeds I posted above.
Obviously they are not accurate
The GPS was providing position information that conflicted with data from the other sensors.
The flight controller can't deal with crazy data so it ignores it.

 

[With The Birds]

Your compass was reporting a yaw rate exceeding 250deg/s at 6:41 into the flight, this is abnormal. When the compass and GPS data don't agree the flight controller will ignore the GPS data entering ATTI mode.

Was it windy? Wind speed during the flight is reported as 7.2ms average with 9.9ms gusts (22mph). Not too windy to fly however would see you drifting nicely in ATTI mode if you weren't working to counter the drift.

 

[kevinp3s]

thanks guys ...should I check anything on the phantom or remote.... are any of the of sensors , GPS or compass faulty?

 

[madmaximum]

Mine gives a compass error and goes into ATTI mode occasionally. I just bring it back and restart everything and usually it's fine.

 

[kevinp3s]

So if the drone goes into Atti mode while its in RTH mode what will happen

 

[msinger]

So if the drone goes into Atti mode while its in RTH mode what will happen

It will auto land at its current location.

 

[kevinp3s]

okay thanks .. I was worried it might just stop and hover...

 

[bojtren]

Same problem... DJI Flight Log Viewer - PhantomHelp.com

 

[kevinp3s]

I see you were getting some Magnetic Field Interference...do you know what caused that .....that might have being the cause of the P3S to go into ATTI MODE