Quality Assessment for GNSS Relative Positioning under Topographic Obstruction

As the spatial information technology advances, one could easily have access to high quality digital terrain data (e.g., digital surface model, digital elevation model, etc.). This advance also makes possible an accurate analysis for the topographic effects in the Global Navigation Satellite System (GNSS) positioning task. In this study, an integrated approach for analyzing the impact of topographic obstruction on GNSS relative positioning has been established and verified by numerical validations. Results from case studies reveals that, by incorporating terrain data in an analysis, the rate of successfully predicted number of satellites has been improved by 40%. It illustrates that the topographic effect should be an essential consideration in a satellite surveying. Additionally, the proposed methodology was also applied successfully to three related tasks, including baseline accuracy assessment, base station location optimization, and GPS network desification. Consequently, the reliability for a satellite surveying and its related applications can now be significantly improved by incorporating the proposed approach.