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Phantom 4 RTK - PPK processing

Is someone processing ppk in Pix4d with success? I tried to merge a PPK CSV with my Data but there seems to be a problem. The Pix4d is only using one horizontal value but we have two, Long- and Latitude. Here is my workflow. Can someone tell me, what I did wrong? 

Hi Mario,

The reason why the values are not recognized is that, in order to import the accuracy values using the text file, the omega, phi and kappa angles need to be included in the file. As described in the Input Files article, the following format is expected:

imagename,latitude [decimal degrees],longitude [decimal degrees],altitude [meter],omega [degrees],phi [degrees],kappa [degrees],Accuracy Horz [meter],Accuracy Vert [meter]

The following workarounds can be used:  

a. Changing all the values at once to the same value in the Image Properties Editor. 

  1. Create the project from scratch.
  2. Right click  one cell of the column in the image properties editor.
  3. Click  Edit All Altitudes / Horz. Accuracies / Vert. Accuracies.
  4. Type the new value.
  5. Click Enter or click outside the cell.

b. Editing the .csv file so it also contains the omega, phi, kappa angles:

  1. Create the project from scratch.
  2. Export the image geolocation by using the “To File…” option in the Image Properties Editor.
  3. Edit the exported file/ add the accuracy values at the end of the lines (excel, notepad).
  4. Import the image geolocation file by using the “From File…” option in the Image Properties Editor.

At the moment, it is possible to import and define the Accuracy Horz and Accuracy Vert values, and not also separate values for X and Y. To compute the Accuracy Horz we calculate the average value of the RtkStdLon and RtkStdLat.

In your specific case, the input file would look like this:

Best,

Brian posted a similar question in the Processing settings DJI Phantom 4 RTK community post. 

More specifically, the question is about values to use in Pix4D when using the Propeller Aero solution for post-processing the P4RTK flights. 

As Brian mentioned, it is not possible to import separate values for all the directions (East / North / Up) and I would recommend:

  • Accuracy Horz - calculate the average value of RMS Error East and West.
  • Accuracy Vert  - use the value RMS Error Up.
  • Creating a custom csv file as mentioned in the previous comment (b. Editing the .csv file so it also contains the omega, phi, kappa angles). 

@Brian, could you give more information about the coordinate systems you are using? I noticed that you are using the projected coordinate system (2., 3.) and orthometric heights (4.). 

Washington State Plane South NAD83 (2011)

 

Thanks for the response. Looking forward to giving it a try.

Since the image coordinate values are in ft(US) I would also recommend converting the RMS Error values to ft(US).

Hello Blaž,

 

I’m also struggling to get a project coordinate system to work from Propeller. Does the image coordinate system ever get changed? We can download the corrected drone position csv in XYZ, but that is only an option to import the image locations if the coordinate system is changed. Converting everything to Lat/Long/Alt and continuing with WGS84 I am still unable to get an output that is accurate in Michigan South State Planes Int. Feet. Any help would be appreciated.

Chad

I changed the image coordinate system to state plane in the image properties dialogue.

Feel free to hit me up on email Brian@mailagc.com. It’d be nice to compare notes worth someone using the same mixed propeller/pix4d workflow.workflow.

Brian

Hi Chad,

As Brian mentioned, it is possible to change the image coordinate system and use the projected coordinates in the Image Properties Editor:

If the vertical coordinate system for the image geolocations is not one of the predefined in Pix4D (EGM84, EGM96, EGM2008 geoid models or ellipsoidal heights), I would also change the vertical coordinate system settings as mentioned in this comment