GPS failed - lesson learned

[martin19117]

That's true hrosee. Atti is fun to fly also

 

[dchao]

Dchao. I do move location. I normally alway fly in 3 locations but they are far from each other. About 20-30 miles each location. So am I do it correctly by recalibrate the com.

yes, also because your altitude could have changed as well. the angle of magnetic field could be different, it would be prudent to do a re-calibration.

 

[martin19117]

Cool. Thanks. I'm still learning but having fun. It's a good stress reliever

 

[Meta4]

Dchao. I do move location. I normally alway fly in 3 locations but they are far from each other. About 20-30 miles each location. So am I do it correctly by recalibrate the com.

yes, also because your laltitude could have changed as well. the angle of magnetic field could be different, it would be prudent to do a re-calibration.

Travelling 20-30 miles makes no difference.
Even traveling 100 miles makes no difference.
There is no need to recalibrate because of that.

 

[martin19117]

Travelling 20-30 miles makes no difference.
Even traveling 100 miles makes no difference.
There is no need to recalibrate because of that.

oh ok I see, I didn't know that. thanks for the info.

 

[dangrand1103]

Unlucky man did you have it insured or under warranty? Really considering getting mine insured after hearing about all these stories and seeing my old one randomly drop out of the sky.

Hi There...there is an app called "Verify"...its an insurance app for the drone. You click on it "get insured" and for an hour of $1M insurance it costs $10

 

[bhartwell]

From what I see on the Verify site, coverage is for liability only. So, a damaged or lost drone is not covered.

 

[BudWalker]

Thanks. File uploaded.
DJI Phantom & Mavic Flight Log Viewer - PhantomHelp.com

Looks like it could have been a compass issue after takeoff that then led to the GPS dropping out.
The yaw errors towards the end were probably me trying to recalibrate after I landed.

This flight has all the characteristics of having been launched from a geomagnetically distorted location. In this kind of situation the Yaw value will be incorrect because it was set from a compass value that is incorrect due to the geomagnetic distortion. After launch when the P3 is clear of the distortion the compass values become correct but the Yaw is remains incorrect because it depends mostly on the IMU. This inconsistency is what causes the compass error that you see in the Go App.

By looking at the direction of flight and controls it's possible to determine the AC heading. And then compare that heading against the yaw value. This incident is a little difficult because some rudder input was applied right after launch. But, at 8.41 secs no rudder was being applied, the yaw value was -55 and the P3's direction of flight was about -160 degrees. Shortly after that, at about 9.45 the COMPASS_ERROR_LARGE error was indicated

Having the .DAT would let us know for sure. But, it's almost certain that the cause of this incident was launching from a geomagnetically distorted site.

 

[Sharky]

This flight has all the characteristics of having been launched from a geomagnetically distorted location.

Thanks for the detailed explanation.
Seems like I launched from a not so ideal location on this one and got lucky.
Good lesson learned.