Today something strange happened. I put the Spark into sport and pushed the forward stick but it consitently veered to the left by about 20-25 degrees. Put it back into GPS mode and it was fine. No error messages. Checked compass and IMU settings in the app before and during flight and everything looked normal. What could this be?
Also, I can see the log in my DJI app but for some reason it won't sync to AirData via HDSync.

Here's part of the video where the behavior occured. I'm aiming/steering toward the pool house but you can see that the AC flies toward me instead. The wind was very calm. GPS signal was good.

Got it uploaded to AirData: http://app.airdata.com/main?share=OOjjPx. Also noticed that the AC was yawing slowly when stationary. Would do that about 5-10 degrees or so and stop. I've noticed that behavior in other locations and while in GPS mode too. Not sure if it's related.

Try first to fly higher in sport. And on a different location.
I am not sure, if the vis system is active in sport or not.
And may have problem to track the gras.
I encounter sometimes drifting in normal mode and slowflight, if in the shadows under trees.

But in case it is still happening there, this will be something for DJI

ernie_halter Posted at 2017-12-3 16:44
Got it uploaded to AirData: http://app.airdata.com/main?share=OOjjPx. Also noticed that the AC was yawing slowly when stationary. Would do that about 5-10 degrees or so and stop. I've noticed that behavior in other locations and while in GPS mode too. Not sure if it's related.

VPS needs a good textured flooring and good lighting conditions, this can cause aircraft to veer off line you need to fly at higher altitude to check this correctly above 10 metres.

hallmark007 Posted at 2017-12-3 17:59
VPS needs a good textured flooring and good lighting conditions, this can cause aircraft to veer off line you need to fly at higher altitude to check this correctly above 10 metres.

will definitely try at above 30m. curious though as to why gps mode would be any different all else being equal?

Hi, Ernie. Please try to calibrate the compass and IMU before flight. I would recommend you fly in a low wind environment to test your spark. If the problem still remains, please upload the flight data to dropbox and provide it to us. Thanks.

ernie_halter Posted at 2017-12-3 18:58
will definitely try at above 30m. curious though as to why gps mode would be any different all else being equal?

It’s not gps but VPs “Vision position system” this is what is used at low altitude to hold a lock between ground and aircraft above 10 metres aircraft uses barometer to lock its position to the ground and gps to hold aircrafts position.

Either VPS messes with direction or your sticks need calibration. Couple of degrees could be attributed to you not going directly straight but 20, 25 deg is way too much.
As for rotation, yes, it tends to rotate without the stick input as part of the inertia after yaw rotation is still present and pesky Spark compass cannot notice it. Gains are on softer side (good, especially for beginners and for filming) so that also contributes to longer stop times.