Abstract&nbsp;Although the satellite navigation system is convenient, it is difficult to use in a system which requires high reliability such as autonomous driving and unmanned delivery because the signal strength is weak and it is vulnerable. In urban area, satellite signals are blocked and a position error increases generally. This study proposed a method to improve navigation performance by estimating the pseudorange through the measurement estimation technique when signal abnormalities occur based on the measurement values ​​and correction data. The method is verified through simulation. If the proposed method is applied, the reliability and the usability of the satellite navigation system can be improved.Keywords: GNSS, Performance, Measurement, Urban.&nbsp;1. INTRODUCTION&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The Global Navigation Satellite System(GNSS) is a convenient system that can calculate position and time by receiving satellite navigation signals anywhere in the world. With this characteristic, it can be very useful when used as a navigation system for autonomous driving or unmanned delivery service. However, because the strength of the signal is weak, it is easily affected by surrounding environment error sources. A large position error may occur due to the arrangement of satellites, the visibility of satellites, and the error environment. In particular, in urban areas or canyons, the number of visible satellites decreases due to buildings or mountain obstacles, and multi-path errors occur. As the result, a satellite navigation performance declined[1].&nbsp;2. MEASUREMENT ESTIMATION METHODIn order to overcome such performance degradation, the unmanned vehicle is equipped with various heterogeneous sensors ​​or techniques to correct the position based on the map database. However, these techniques has a problem in that errors are accumulated or hardware should be added. Because they don’t have the function to know absolute position, a satellite navigation system should set an initial position or reset the accumulated errors ultimately. In this study, we proposed a technique to maintain the satellite navigation performance by verifying the pseudorange based on the measured values ​​of the satellite navigation receiver without the help of these heterogeneous sensors and databases. This method estimates the pseudoranges and position when an abnormality occurs. In the future, unmanned vehicles to be operated in urban areas are expected to utilize the correction information of the GNSS augmentation system. In this study, anomalies in the satellite navigation signal are detected using the signal strength, pseudorange(code measurement value), and carrier measurement value of the satellite navigation signal with the correction data. After this signal abnormality was detected, the pseudorange is traced using the moving trajectory and correction information.&nbsp;3. CONCLUSIONIt is very convenient to calculate a location using a satellite navigation signal, but improving the reliability of a satellite navigation receiver is not an easy topic considering the intrinsic characteristics of a satellite navigation system. If the performance and reliability is improved, it is possible to simplify the system and reduce the cost of the unmanned vehicle.&nbsp;REFERENCES[1] J. Marais, D. F. Nahimanaa, N. Viandier, E. Duflosa, “GNSS Accuracy enhancement based on pseudo range error estimation in an urban propagation environment,” Expert Systems with Applications, Vol. 40, No. 15, pp. 5956-5964, 2013.

Gnss Performance Enhancement Using Receiver Raw Measurement in Urban Area

Paper Proceedings: https://asmedigitalcollection.asme.org/ISPS/ISPS2021/volume/84799

ASME 2021 Information Storage and Processing Systems (ISPS2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.