Analysis of Planimetric Accuracy of Airborne Laser Scanning Surveys

With the increasing pulse rates of airborne laser scanners point clouds become an interesting data source for mapping beyond the production of digital terrain models. Whereas height accuracy of point clouds is of prime importance for terrain models, mapping of buildings and other objects also requires an analysis of planimetric accuracy of point clouds. This paper presents a methodology to estimate relative strip offsets and standard deviations of Xand Y-coordinates using automatically extracted ridge lines of buildings in overlaps between strips. An analysis of three blocks with 200-250 million points each shows that constant strip offsets explain the majority of planimetric shifts between ridge lines in strip overlaps. It is demonstrated that strip offsets below 3-4 cm and platform positioning noise of only 2 cm can be obtained with GPS configurations consisting of two onboard receivers and multiple reference stations in the terrain and a low flying height.