基于BDS/GPS数据的中国及周边地区电离层暴层析成像研究

随着我国BDS的逐步建成，其在电离层监测上的应用也在逐步拓展. 凭借卫星类型多样性的特点，BDS卫星数据在电离层监测上可能比GPS卫星带来更多的优势，但能否改进电离层层析成像结果仍值得进一步研究. 文中基于GPS数据电离层层析算法，把BDS中的地球同步轨道（geosynchronous orbit, GEO）卫星、倾斜地球同步轨道（inclined geosynchronous orbit, IGSO）卫星和中轨轨道（medium earth orbit, MEO）卫星数据与GPS数据融合，对2017-09-07—09电离层暴期间中国及周边地区（15～55°N, 70～140°E）上空电离层进行重构. 首先借助SA418和WU430测高仪数据分别讨论了单星座（GPS）与双星座（GPS+BDS）层析对电子密度反演的精度结果；其次对2017-09-08两个扰动最强烈时段的电离层成像结果，包括电子密度剖面图与总电子含量（total electron content, TEC）分布图进行深入研究. 研究结果表明:BDS卫星数据不仅可以改进垂向精度，还可以提高对电离层异常结构的反演精度，融合了BDS数据的电离层层析技术能较为准确地重构出本次电离层暴期间出现在中低纬度的等离子体泡.

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.