Simulation Analysis for Performance Improvements of GNSS-based Positioning in a Road Environment Nam-Hyeok Kim, Chi-Ho Park IT Convergence Division DGIST Daegu, S. Korea {nhkim, chpark}@dgist.ac.kr Soon Ki Jung School of Computer Science and Engineering Kyungpook National University Daegu, S. Korea skjung@knu.ac.kr Abstract— Global Navigation Satellite Systems (GNSSs), such as the Global Positioning System (GPS) in the USA, the GLObal NAvigation Satellite System (GLONASS) in Russia, and the Galileo in the EU, determine a target position using a satellite signal. They are widely used around the globe at this time. However, there is a critical obstacle when attempting to run a navigation system in a land vehicle. In contrast to aircraft or vessels, which operate in open areas without any obstacles, land vehicles must deal with signal occlusion caused by surrounding buildings, skyscrapers and other objects, especially in urban areas. In order to solve this problem, many researchers have studied many different methods, such as GPS/GLONASS-integrated positioning; pseudolite, which produces a signal similar to that of GPS; and GPS/Vision integrated positioning. These studies have mainly focused on integrated positioning methods. In contrast, this paper focuses on the relationship between the position of a new signal generator and positioning error for high-accuracy positioning in GPS shaded areas using simulation analysis. Through this analysis, we confirmed that horizontal positioning error is the lowest (10m) in the urban canyon when the degrees of geometric stability is the best. Keywords- GNSS; Vision; Pseudolite; Simulation. I. INTRODUCTION Global Navigation Satellite Systems (GNSSs), such as the Global Positioning System (GPS) in the USA, the GLObal NAvigation Satellite System (GLONASS) in Russia, and the Galileo in the EU, determine a target position using a satellite signal. At present, they are widely used around the globe. Since Selective Availability (SA) was released, the use of such systems has become prevalent in applications ranging from navigation systems for transportation to mobile smart phones. However, there is a critical obstacle when running the navigation system in land vehicles. In contrast to aircraft or vessels, which operate in open areas without any obstacles, a land vehicle must deal with signal occlusion caused by surrounding buildings, skyscrapers and other objects, especially in urban areas. Many researchers have attempted to solve this problem with various methods, such as GPS/GLONASS-integrated positioning [1], pseudolite, which produces a signal similar to that of GPS [2], and GPS/Vision integrated positioning [3]. These studies have mainly focused on integrated positioning methods with a new signal. In contrast, we focus on the relationship between the position of a new signal generator and positioning error for high-accuracy positioning in GPS shaded areas. For this analysis, we developed a simulator using MATLAB, the configuration of which is described in section 2. The developed simulator generates GPS observation data with a variety of errors, such as ionospheric delays, tropospheric delays and clock errors. Moreover, the simulator filters some signals which are occluded by obstacles such as tall buildings. Using this simulator, GPS positioning errors were analyzed in diverse road environments, such as housing areas and urban canyons. These results are described in section 3. The simulator is also able to generate a new signal virtually and then perform integrated positioning using GPS and the new signal data. In section 4, the integrated positioning errors were analyzed according to the new signal generator’s position. Through this simulation analysis, we found that the accuracy of new signals and their degrees of geometric stability should be considered for highly accurate positioning. This paper starts with the simulator description in section 2, then GPS positioning errors are analyzed in section 3. In section 4, the integrated positioning errors were analyzed. The conclusion of this paper is described in section 5. II. SIMULATOR We developed a simulator to perform an error analysis of GPS positioning and integrated positioning with a new signal to enhance the degree of positioning stability. Figure 1. Configuration of the simulator 178 Copyright (c) IARIA, 2014. ISBN: 978-1-61208-371-1 SIMUL 2014 : The Sixth International Conference on Advances in System Simulation