Investigating Positional Accuracies from unsynchronized independent measurements for autonomous cooperative intelligent transportation systems
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Positional real-time data is an important part of a cooperative intelligent transportation system (C-ITS). In order to maneuver and control such an environment safely and efficiently, each autonomous traffic participant must have information about positional accuracy for themselves and their surroundings. There are a variety of ways to determine and compare positional data of vehicles in motion. GNSS systems are commonly used as a positioning tool in navigation and surveying. With the help of an accurate measurement time, travel trajectories can be predicted. As a result, accurate measurements in both time and position are important in a real-time cooperative system. In order to verify positional accuracies while in motion, a setup where several independent systems are simultaneously tracking the same object might be used. In this thesis, positional accuracies of GNSS Receivers and Total Stations are investigated, analyzed, and compared. Since the two systems are independent and have unsynchronized internal time references, an interpolation must be performed in order to prepare the data for numerical analysis. A wide theoretical background is provided, including insights into the field of GNSS, ITS and positional accuracies. An experiment, tracking a vehicle in motion in real time, was conducted and is described. The resulting datasets have been analyzed, and an interpolation script has been developed, which is explained in detail. The acquired data value results are investigated to determine possible correlations and inaccuracy sources. Strengths and weaknesses of this general approach to verify positional accuracies are discussed. Finally, a short template for what could be done in the future is given.