GNSS accuracies under multipath propagation conditions

One major error source for precise GNSS (Global Navigation Satellite System) kinematic positioning is multipath signal propagation. Therefore, it is very important to get more information about the possible multipath sources in positioning scenarios and the corresponding error in the range and phase measurements. We developed a simulation program based on ray tracing techniques, to predict the multipath signal propagation and the corresponding errors in the code and carrier phase measurements. This can be achieved by the combination of our propagation simulation with the results of the measurements in quasi-standardized propagation scenarios. Through the ray tracing algorithm we computed the objects which reflected the satellite waves from the satellites to the receiver in complex positioning scenarios. Simultaneously we recorded the current measuring data for this propagation scenarios. We found out, that the form of the calculated error histograms are nearly identical for the same reflection conditions. This gives the potential to predict the positioning error of GNSS receivers operating in known scenarios by combining this data with the actual reflection conditions. One step to solve the integrity problem of GNSS applications is to predict the positioning error in difficult propagation scenarios. This is essential for the certification of high precise positioning systems like airplane landing systems or railroad controlling systems. In this paper the major algorithms for solving this problem and the first results are presented.