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Author Topic: Phantom 4 RTK - how to use pictures when flight without RTK?  (Read 1919 times)

Mr.Vain

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Phantom 4 RTK - how to use pictures when flight without RTK?
« on: October 26, 2021, 01:09:29 PM »
Hi!

Probably this is a easy question but i cant figure it out. Sometimes when we fly we loose RTK connection in the air when flying and then it connect again and sometimes we fly a whole flight without RTK. I dont know why this happens but it does.
Anyway, when i try to use this pictures in Agisoft i get a really big error when using my GCP:s. How can i get arround this? It seems like it is something in the metadata wich is telling Agisoft that the accuracy should be like RTK but it isnt. Can anyone give me a workflow of how to do this?

Have a nice day! 


Alexey Pasumansky

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Re: Phantom 4 RTK - how to use pictures when flight without RTK?
« Reply #1 on: November 02, 2021, 05:46:01 PM »
Hello Mr.Vain,

Metashape loads the information regarding the coordinate measurement accuracy for the camera centers from the image metadata, providing that "load camera location accuracy" option is enabled in the Advanced Preferences tab prior to the image import to Metashape project.

According to the screenshot those cameras that are shown in the Reference pane have quite low accuracy imported (about 1.5 meter in XY plane and about 1 m in Z direction), compared to regular RTK/PPK accuracy.

If you need to modify the accuracy values manually, you can select the cameras in the Reference pane, right-click on selection and choose Modify command from the context menu. Then select "Accuracy (m)" field and specify the desired value to be set for all the selected cameras. It could be just single value applied to XYZ coordinates or a "slash" separator can be used to define XY/Z or X/Y/Z accuracy individually.

In case most of the cameras still have valid high accuracy values, try to run Optimize Cameras operation with all the calibration parameters enabled and also enable "fit additional corrections" option, then use check points for the validation of the project accuracy.
Best regards,
Alexey Pasumansky,
Agisoft LLC

dpitman

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Re: Phantom 4 RTK - how to use pictures when flight without RTK?
« Reply #2 on: November 07, 2021, 07:42:13 PM »


Metashape loads the information regarding the coordinate measurement accuracy for the camera centers from the image metadata,

Hi Alexey,

I have purchased an Autel Evo 2 Enterprise RTK (E2E) and so I am trying to make sure I adjust my workflow where appropriate to take advantage of the precision gnss.

In the E2E image exif, there is indeed the accuracy values for GPS x/y and GPS z.  Do you (or anyone) know how that value is determined by the drone when it writes those values in the EXIF?

Thank you,
Dave