That is great news from a real world application of this PPK solution. Is it also correct that the X4S must be calibrated to their specifications so that a specific pixel is selected as the geospatial reference point for each image? Are your flights conducted with the camera facing directly downward? Are your 100ha (247 acre) flights performed with more than 1 set of batteries on the Inspire 2
( a couple of adjoining flights)? How many images are taken to cover the 100ha? Are you using a dual frequency GPS to store the data and convert to RINEX format? Does your setup also use a ground base plus rover setup to provide ground location tie in or perhaps your mapping is not required to have a ground tie in? Are you using the AirGon flight mapping application and does it provide terrain follow capability that adjust AGL automatically? Is your data then gathered and edited with Agisoft for processing with LP306 application?
I hope that I am not asking too many questions, it is just that the accuracy which you are getting with 400 ft AGL and not using GCP's is quite good for this solution and many other forum members might not know about this technology which is all available from the GeoCue Group corporation in the USA.
Thank you again for sharing your real world experience with us here on the forum.