Extreme Precision Lidar Mapping

To advance earthquake research, a unique LiDAR (Light Detection and Ranging) survey was conducted to map an approximately 1,000 km segment of the San Andreas Fault in southern California in the spring of 2005. The objective was to produce a surface model along the fault line at extremely high accuracy and consequently, extraordinary care was devoted to all the system components and the mission planning of the LiDAR survey. A dense network of GPS reference stations was established in addition to the PBO (Plate Boundary Observation) system to provide short baselines for the sensor platform orientation. The Optech 3100 ALTM system was operated at a 70 kHz pulse rate, which provided an optimum in terms of balancing the requirements for good ranging accuracy, large area coverage and high point density. For quality control, including systematic error corrections, conventional profiles were collected and LiDAR-specific targets were used. These targets not only provided for the vertical correction, but were also able to improve the horizontal accuracy. This paper provides a brief project overview and a preliminary analysis of the achieved accuracy.