Abstract: Aiming at the difficulty of laying control points on the river's belt-like complex terrain and high-precision measurement requirements, a non-GCPs monitoring method for rivers and lakes combined with PPK technology is discussed. The DJI Phantom 4 RTK UAV is used as the research object,the key technologies that affect the accuracy of aerial surveys, such as high-precision POS assisted airborne triangulation based on PPK, camera lens distortion correction, and route designare analyzed,ground base station and UAV POS data by UAV-PPK software calculated, combined with the GNSS post-difference processing technology to obtain high-precision POS data to assist aerial triangulation. Combined with Zhuangmu River regulation project to carry out experiments,the analysis of POS data and mapping accuracy shows that based on PPK's Non-GCPs UAV aerial survey, high-precision POS data assisted aerial three surveys are obtained, and the precision of the results meets the requirements for 1:500 large-scale mapping of river channels. PPK aided UAV for aerial survey improves the precision of surveying and mapping of complex terrain, and provides accurate data support for subsequent comprehensive river regulation work.

Key words: river surveying, GNSS post difference, non-GCPs, UAV, precisiony analysis