Accurate outdoor ground truth based on total stations
This work addresses the need for precise outdoor ground truth in robotics for developing mapping and localization algorithms, though it is incremental as it extends existing total station methods from 3-DOF to 6-DOF.
The paper tackled the problem of obtaining accurate 6-DOF ground-truth poses for vehicles in outdoor environments by using three total stations to track three prisms, achieving an average positional error of 10 mm and 0.6 deg, which outperformed RTK solutions especially in GNSS-challenged areas like forests.
In robotics, accurate ground-truth position fostered the development of mapping and localization algorithms through the creation of cornerstone datasets. In outdoor environments and over long distances, total stations are the most accurate and precise measurement instruments for this purpose. Most total station-based systems in the literature are limited to three Degrees Of Freedoms (DOFs), due to the use of a single-prism tracking approach. In this paper, we present preliminary work on measuring a full pose of a vehicle, bringing the referencing system to six DOFs. Three total stations are used to track in real time three prisms attached to a target platform. We describe the structure of the referencing system and the protocol for acquiring the ground truth with this system. We evaluated its precision in a variety of different outdoor environments, ranging from open-sky to forest trails, and compare this system with another popular source of reference position, the Real Time Kinematics (RTK) positioning solution. Results show that our approach is the most precise, reaching an average positional error of 10 mm and 0.6 deg. This difference in performance was particularly stark in environments where Global Navigation Satellite System (GNSS) signals can be weaker due to overreaching vegetation.