Imaging of the ionospheric storm over China and adjacent areas with BDS/GPS data

With the gradual completion of the BeiDou Navigation Satellite System (BDS) developed by china, its applications in monitoring of ionospheric is gradually expanding. Due to the feature of satellite diversity, BDS data may bring more advantages than GPS in ionospheric monitoring, more work needs to be done to discuss whether BDS data can improve the results of ionospheric tomography. In this paper, an ionospheric tomography algorithm based on GPS data, combined with the BDS data is proposed to reconstruct the ionosphere over China and adjacent areas（15-55°N, 70-140°E）during the period of ionospheric storm on Sep. 7−9, 2017. BDS data consist of geosynchronous orbit (GEO) satellites data, inclined geosynchronous orbit (IGSO) satellites data and medium earth orbit (MEO) satellites data. First, the accuracy of inversions using the double-constellation(GPS+BDS) tomographic algorithm and single-constellation（GPS）tomographic algorithm is discussed by comparing with SA418 and WU430 ionosonde data. Secondly, we have made a further study of ionospheric imaging results, include that electron density profiles and total electron content（TEC）maps during the two periods with the strongest disturbance on September 8, 2017. The results show that BDS data can improve not only the vertical accuracy but the accuracy of inversions of structural abnormalities in ionospheric. For example, plasma bubbles over the middle and lower latitude region are more accurate inverted by using this method during the ionospheric storm.