NLOS mitigation techniques in GNSS receivers based on Level Crossing Rates (LCR) of correlation outputs

摘要

Global Navigation Satellite Systems (GNSS) provide navigation services with a highly precise estimation of the position. First military influenced, the use of satellite-based positioning has gained a lot of interest also in civilian tasks nowadays. Because the GNSS performance has been improved over the years, the state-of-the-art GNSS navigation does include indoor positioning and moving autonomously with help of GNSS. The accuracy, which essentially has to be high, can be disturbed by multipath (e.g. diffraction, reflection, refraction or scattering). A possibility to detect multipath, and possibly to avoid those signals in the position solution, is totally necessary. A non-direct signal, namely Non-Light-of-Sight (NLOS), can lead to low accuracy of the positioning.Therefore, this thesis is dealing with the NLOS detection by using the Level Crossing Rate (LCR), which has been used in electronic communication such as Wifi. The thesis is divided in two parts, including a literature review part, following by a simulation of the developed detection technique. All basic knowledge about this work can be extracted from the literature part. In the simulation section, several tests will be provided, done by Matlab simulations. To perform a realistic GNSS signal, a dynamic Galileo Composite Binary Offset Carrier (CBOC) signal was produced.