I have successfully tested these days the new version of the Mettatec´s X5 GNSS PPK module for the DJI Phantom 4 Pro drone, that now includes a faster connection to the satellites, improved decimeter precision and the option to download files not only through the MicroSD card but also by Wifi. It’s just turn on and fly! It connects faster to satellites than the drone. It has allowed me to continue working, despite the years, with my Phantom 4 Pro! Great!
I can get centimeter accuracy in PPK mode using an Emlid RS2 base or any other multi-band GNSS receiver that delivers files that can be converted to RINEX format.