Quantitatively Evaluating Random Attitude Measurement Errors' Impacts on DSM Elevation Accuracy From Airborne Laser Scanning

Impacts of random attitude measurement errors (RAME) made by the global positioning system (GPS)/inertial measurement unit (IMU) integrated system on elevation accuracy of a digital surface model (DSM) reconstructed from an airborne laser scanning (ALS) system were evaluated. By numerical simulation, three common terrain models, i.e., a planar, a rectangular, and a hemispheric terrain model, were established, and the scanning processes of the ALS system for the three terrain models were simulated to analyze the effects of RAME on reconstructed DSMs. Furthermore, a semi-physical simulation experimental setup was constructed to verify the results obtained from the numerical simulation. A physical terrain model was scanned to quantitatively evaluate the impacts of RAME on positioning accuracy of a laser point cloud and elevation accuracy of a reconstructed DSM. Experimental results show that under the condition of experimental “flight” height of 1310 mm and affected by two kinds of RAME with different standard deviations, i.e., 0.01° and 0.1°, the RMS values of elevation error of reconstructed DSMs increase 0.04 and 1.56 mm, respectively, corresponding to 0.015 and 0.595 m at actual flight height of 500 m. Therefore, if the elevation error of a reconstructed DSM caused by RAME is requested to be lower than 1 cm under the condition of flight height of 500 m, the random attitude measurement accuracy of the GPS/IMU integrated system should be higher than 0.01° (1σ) at least.