Reach PPK using Pixhawk


I want to geotag my pictures using PPK for photogrammetry. The Pixhawk uses its standard GPS unit and I would like to add the Reach as second GPS-unit. Is it possible to use the standard Ardupilot firmware (not px4-reach with ERB) and get a standard(= not corrected) GPS signal for Pixhawk from Reach ? If yes, what do I have to do ?

Thank you for your help.