Acquiring reliable fixed GNSS solutions under a dense forest canopy is typically unattainable even in more sparse forest stands. Required is not only the accurate global positioning of complete forest stands for UAV- and satellite-based time series analysis, however also for determining or establishing permanent measurements of ground points for field crews. Traditional aerial photogrammetric methods involving Ground Control Points (GCPs) are a challenge in forested areas due to high costs when measured with a total station, float GNSS solutions (sub 2 meter accuracies), moving tree crowns during windy conditions as well as GCP aerial visibility. Recent developments in off-the-shelf RTK-GNSS supported UAVs has provided the potential to map forest stands with fixed GNSS solutions in a rapid manner without or a minimal use of GCPs. This study was carried out at the Britz research station for intensive forest monitoring implementing a configuration of 51 GCPs for validation measured with a total station. A method was developed to acquire ground measurements of a forest stand with aerially visible targets resulting with sub-decimeter accuracies before post processing.
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15-UAV RTK-GNSS finally a solution for forest mapping-StuartKrause