Global Ionosphere Estimation Based on Data Fusion From Multisource: Multi-GNSS, IRI Model, and Satellite Altimetry

摘要

Traditionally, the ionosphere determination just uses American Global Positioning System and Russian GLObal NAvigation Satellite System dual-frequency data and has a low precision particularly on oceans. With the rapid development of Chinese BeiDou and European Galileo systems, they are playing an increasingly important role for modeling global ionosphere. Meanwhile, satellite altimetry provides valuable and precise ionosphere delay over the oceans. Through introducing priori ionosphere values from an advanced empirical ionosphere model, combining the advantages of Global Navigation Satellite System (GNSS) and satellite altimetry technologies, the precision of global ionosphere estimation can be further improved. To assess the improvement, we collect satellite altimetry data from Jason-2/3 and more than 300 global GNSS stations, the data are processed in 2014 and 2018 when the Sun is in a high and a low activity conditions. The results suggest that the ionosphere determination based on multitechnique fusion in a solar-geomagnetic reference frame is well suitable to represent the ionosphere and its structure. The determined ionosphere achieves a better global consistency, and its formal accuracy is significantly reduced. By comparing with the International GNSS Service products, evaluating by satellite altimetry measurements,and independently validating with ionosonde techniques, it is proved that the ionosphere results are further improved through employing additional available data, especially for the ionosphere over the oceans.