Developing innovative and cost-effective UAS-PPK module for generating high-accuracy digital surface model

Abstract

Traditional indirect georeferencing requires time-consuming and labor-intensive field surveys to obtain ground control points (GCPs), making it challenging to apply in high-risk areas with limited accessibility. This study proposes a novel and low-cost system for direct georeferencing using unmanned aerial system post-processing kinematics (UAS-PPK), which is less than a quarter of the price of commercially available products. To evaluate the accuracy of the aerial surveys of the custom-built module and digital surface models, we used 15 checkpoints (CPs) and 99 validation points (VPs). The results showed that this UAS-PPK module could deliver high-precision aerial surveys with a root mean square error (RMSE) of less than 4 cm for three dimensions without using control points. After adding one GCP, the RMSE of three dimensions was close to that of traditional aerial survey methods using 12 GCPs, having a vertical accuracy of 2.51 cm. The same 99 VPs were used to evaluate the accuracy of the digital surface model produced using UAS-PPK. The results showed that the accuracy was close to that of traditional aerial survey methods, having an average error of less than 3 cm. We demonstrated the self-made attachable UAS-PPK module to be a reliable and accurate survey tool in geoscience applications.