Exif data wrong?

[dooom]

Hi, I'm using the exif data from my Mavic 2 zoom to make some calculations in geo referencing software and I noticed some pretty bad results.

For example I have two pictures taken successively at the same hight, and angles. The pictures look the same, and matches pretty good on overlay, but the gimbalYaw angle in the exif data differs with over 90 degrees.

When matching with the real environment I can tell that one is clearly closer to reality than the other. But how reliable is this data? What causes these result difference? And is there anything I can do to prevent it?

// Dooom

 

[sar104]

The gimbal yaw looks fine in all the images that I've checked. How does the gimbal yaw compare to the flight yaw in those images?

 

[dooom]

Here's an example pf two pictures where I notised a big difference:
DJI_0178: gimbalYaw = 97.8, flightYaw = 167.1
DJI_0180: gimbalYaw = 163.3, flightYaw = 177.7

I have some with an even bigger difference.

Edit: Removed images due to legal uncertainty

 

[sar104]

0178 does seem to be wrong. You need to take a look at the txt log file for that flight, which contains the full set of recorded telemetry including gimbal data.

TXT log: DJI Flight Log Viewer | Phantom Help

 

[dooom]

Unfortunately I don't have access to the flight logs, but do you have any idea about what could cause issues like this? Compass calibration? Firmware?

 

[sar104]

Unfortunately I don't have access to the flight logs, but do you have any idea about what could cause issues like this? Compass calibration? Firmware?

No - I've not seen that before. What is curious is that the two images you posted were only taken 4 seconds apart, which doesn't leave much room for it to be a gimbal calibration issue. And the aircraft yaw values are consistent, so it doesn't seem like a compass issue either.

 

[dooom]

Thanks a lot for the responses anyway, glad to see that I'm not the only one being confused.

 

[ndepal]

Did you ever find out more about this? I'm facing a similar problem where I flew a mission with a Mavic Pro using the Pix4d Mapper app. Some images have Gimbal Roll Degree: +179.90 in the EXIF/XMP data, while most others are around 0. From the image itself it's obvious that a value of ~180 deg is wrong. This is causing problems with the Pix4d reconstruction as those images are pointing to the sky.