Yes Sir. We perform around 400 flights/year and about 75% of them utilize GCP's and 50% of those use PPK. Most of our use revolves around construction excavation processes and other topographic surveys and getting the drone data back into real design software to analyze. Not the so-called analysis tools that most of the photogrammetry solutions provide. We work within a tolerance of 5cm as I have found that to be a realistic goal that is pretty easily achievable. We have gotten down to 2cm, but it's really not worth the hassle for what we do. If it's that critical we are using a GNSS receiver or even a robotic total station.chascoadmin, I take it you need to do precision survey work?