Integration of Terrestrial Laser Scanner for Ground Navigation in Gps-challenged Environments

GPS/INS integration can provide high accuracy (centimeter level) navigation under good satellite geometry and atmospheric conditions. However, due to GPS signal blockage and accumulative error attributes of INS, a GPS/INS system cannot continuously maintain such high accuracy navigation during GPS outages, which may frequently happen in terrestrial applications, such as when navigating in forested areas. Imaging sensors can provide adequate data to support navigation in these situations. Due to its high accuracy and efficient range measuring capabilities, we propose the integration of a terrestrial laser scanner into a navigation system, primarily for calibrating the INS. To attain centimeter level navigation accuracy in any environment under heavy canopy, spherical objects are placed around the navigation area; they remain stationary during navigation. Using a conic search window, a spherical point cloud search is performed. Then, the center positions of the spheres are determined by a least squares method. Sphere centers extracted from different scans are registered based on their topology, and the differences between the scanner’s positions and attitudes at different scanning sites, the relative positioning result in a local coordinate frame, are accurately computed and subsequently used for the calibration of the INS. This paper discusses the integration of a terrestrial laser scanner into a GPS/INS/pseudolite (terrestrial RF system) integrated terrestrial navigation system, and provides preliminary simulation test results. * Corresponding author.