RTK settings for PPK

I want to use one Reach as base on known coordinates while the 2nd Reach is on a Fixed-wing UAV for images geotagging.

  1. what “Position mode” and what “GPS AR mode” should I use for base and what for Rover?
  2. should I turn off “correction output” in the “base mode” tab?

Thanks.

1.For moving rover, use kinematic and GPS AR on. For base, it really doesnt matter as long as you set the correct known coordinates (if you need absolute and not relative position. Average position is an option if you dont need absolute and correct coordinates) and activate base mode and forward signals to rover.
2. No output is needed, you can use base mode for out and correction data to rover, from rover you can e.g use output data to visually see output processed solution.
So, in base mode menu, you need to activate correction output to give correction data to rover.

But for the purpose of just post processing and either of above is not needed, you only need to enable raw logging in the logging menu for both units and reading this for the rest https://docs.emlid.com/reach/gps-post-processing/.
I assume you have the camera trigger setup ok.

Like this for instance

Thanks.
What GPS AR mode should I use? conteneous, Instentaneous or Fix-and-Hold?

Continuous and Fix/hold usually does the trick.
Fix/hold could give you easier fix, but with corrupted data it can give ofset and not right coordinates. Its a bit complex but try continuous first and fix/hold second.