Multipath Mitigation Technique Based on Modifications to GNSS Monitor Station Antennas Field

Abstract

Monitor station is an important part of global navigation satellite system (GNSS) ground operating and control system. The quality of the observation data by GNSS monitor stations directly influences the precision of positioning, navigation and timing (PNT) provided by the GNSS system. Multipath effect is one of the major error factors, which causes the precision decrease and quality deterioration of observations. In general, both the GNSS receiver’s multipath mitigation techniques based on hardware processing and the monitor system multipath mitigation techniques based on data post-processing are adopted to improve the quality of observation data. However, for the limit of receiver’s hardware resources, manufacture techniques and the system’s real-time requests, the application of the two techniques cannot make the quality of observation data meet the system’s requirement. According to the characteristic of multipath signals, this paper proposes a novel installation which is named RF absorbing nest to further suppress multipath effect around the antenna field. With the absorbing nest, on the one hand the multipath signals from horizon or below are mitigated in effect, on the other hand the direct signals is effectively reflected from the inside surface of the foam. The experimental results show that the quality of the monitor stations’ observation data improves 20–40% and the precision of processing for ionosphere model and wide area difference is improved effectively.