A 3D Color Terrain Modeling System for Small Autonomous Helicopters

This thesis develops a novel aerial terrain modeling system. The system is unique since it flies onboard a small autonomous helicopter and senses the structure and color of its surroundings to build accurate 3D terrain models. The system is capable of modeling terrain where current approaches are too expensive, too dangerous, or too difficult. The prototype system is primarily composed of a mechanically aligned laser rangefinder and 1-pixel color camera, viewing the terrain through a common scan mechanism. The merit of this sensing approach is that range and color measurements are inherently collected from an identical terrain location. This thesis presents a novel sensor, calibration methodology, and synchronization approach for a working terrain sensor prototype. The prototype’s performance was verified by carrying out a number of real-world mapping missions. These missions range from geological feature modeling in the Arctic for NASA scientists, to mapping an urban building complex for DARPA researchers. The system has proven to be effective in over 50 modeling flights, which produced terrain models accurate to <20cm in 3D.