Hydrographical survey using point cloud data from laser scanner and echo sounder

This research proposes a hydrographical survey technique using combined point cloud data from rotating echo sounder and two fixed laser scanners and correcting instantaneous position and orientation from GPS and IMU data to reconstructed a three-dimensional environment image. As a result, river/canal depth and bank slope/height can be measured. All survey sensors can be installed on a 1.6-m long remote-control catamaran to effectively measure data from river/canal with width less than 160 m. Then, the hydrographic information, including cross section, section width and bank height, could be extracted from the reconstructed image. Furthermore, measurement accuracies of reconstructed images from laser- and echo sounder-cloud points are validated against fixed size objects, located at various locations, and specified water channel, respectively. Laser and echo sounder maximum measurement error are (15%, 6%) and (8%, 6%) along horizontal and vertical directions, respectively.