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DJI MATRICE 210 RTK - DJI Zenmuse X7 - Accuracy issues

Hi all,

Recently, my company purchased a brand new drone and i get to do some testing with the images in Pix4Dmapper.

Everything gone through without any issues apart of the accuracy which is out for about a meter in average.

I was wandering if it’s anything that i can do to improve its accuracy apart of GCPs (which i’ve tried to add but it didn’t make a difference)

Just to add that i was trying to use the data on a free trial Pix4Dmapper licence (although I don’t believe this is the issue)

Any suggestions will be muchly appreciated.

Many thanks!

Could you share the Quality Report?

Hi Dan,

As Jaakko mentioned, a quality report would help us get a better insight into what processing options were used.

Cheers,
Teodora

Hi both,

Firstly, many thanks for your time to answer my questions. :smile:

Please see the link below to the quality report generated from the last process. No GCP were used for this last batch.

In this area it’s an OS trig point with fixed coordinates: EASTING - 482270.27, NORTHING - 369710.73

This coordinate falls right in the centre of the pillar but when i’m checking this in the reconstructed data is about 1.5m away from the pillar (in both point cloud and orthomosaic)

I’ve been using Arcmap for the accuracy of the Orthomosaic and Civil 3D for Point Cloud.

Thank you!

Hi Dan,

Thanks for sharing the QR.

Please note that, if you have images with very accurate geotags (RTK/PPK datasets), you need to adjust the x,y,z accuracy values (Accuracy Horz and Accuracy Vert) in the Image Properties Editor . The default accuracy in Pix4Dmapper is 5 m and 10 m as you can see in the screenshot below. When using RTK/PPK technology, the image accuracy should be much better (few centimeters - 0.02 m is usually set for the vertical and horizontal accuracy). Please check that the accuracy of your images is set correctly in the Image Properties Editor, because the software needs to know how much to trust these coordinates, so setting the correct accuracy is crucial. This community post can shed some light on this topic: Accuracy of image collection with RTK.

One other factor to consider is the coordinate system used in this project (OSGB 36). If a horizontal coordinate system transformation is required to accurately transform your project’s Image Geolocation Coordinate System or GCP Coordinate System to your project’s Output Coordinate System, you must transform your project’s inputs’ coordinate system to your project’s Output Coordinate System before processing your project. Please follow the steps from this community post and let us know if the project results have been improved: Horizontal grid corrections and transformations.

Hopefully this helps.

Best,
Teodora

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Hey Teodora,

Thank you ever so much for your suggestions.

We did manage to tie up the accuracy much better by tweaking some of the RTK’s settings and also by using several GCPs with precise coordinates.

As for the coordinates transformation, we did encounter some difficulties using OS website but we developed a different method which did the job.

Again, i wish to thank you for your support!

Have a lovely day!

Dan N

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