GPS/ INS for direct georeferencing of LIDAR imagery

Georeferencing is a vital task in remote sensing where the content of images is geometrically referred to an earth- fixed coordinate frame. This requires the determination of the exterior orientation (i.e. position and attitude) of the image sensor at the time of recording. While "traditional" techniques rely an the use of ground control points and (aero-) triangulation for blocks of images, direct georeferencing is achieved by determing the time-variant exterior orientation of the image sensor by a suitable combination of navigation systems. A very successful approach is the integration of the Global Positioning System (GPS) with an inertial navigation system (INS). This technique is already widely applied for passive image sensors (optical cameras) and almost indispensable for active sensors. In case of light detection and ranging (LIDAR), the scene is scanned by a rotating laser beam. LIDAR provides several thousand range measurements per second, still, possible motions and rotations of the sensor while scanning must be accounted for. This problem is a current research topic in remote sensing and navigation. The planned research project deals with a portable LIDAR-based remote-sensing system equipped with GPS/INS developed at the Ecole Polytechnique Federale de Lausanne. The portability of the system makes it a tailored tool for environmental monitoring purposes like avalanche or landslide monitoring from helicopters or light aircraft. The primary scientific objectives of the project are the investigation and further development of suitable methods for the direct georeferencing of LIDAR imagery by GPS/INS, sensor and system calibration, and an in-depth quality analysis. The research emphasis is placed an integrated navigation and sensor fusion.