Ionospheric data assimilation using satellite observations

地球的电离层影响无线电传播，是通信、导航和监视系统的兴趣所在。巴斯大学的研究小组利用地面和空间观测对电离层数据同化进行了广泛的研究。但是，有新的机会利用近距离近地轨道卫星的观测资料进行高分辨率电离层同化成像项目。这些卫星被命名为CIRCE，将有2个关键仪器：一个GNSS接收器（TOPCAT）和一个光学成像仪（Tri-tip）。该博士旨在通过开发数据同化算法来克服成像的挑战，并研究如何将GNSS和光学数据结合成统一的输出。目的和目标：项目的可交付成果包括三个关键里程碑。利用GNSS数据进行数据同化。使用国际参考电离层模型（IRI）创建一个模拟环境，范围从80公里到1000公里。b.集成通过模拟LEO卫星到GNSS卫星的观测。创建算法，将LEO观测“合并”到IRI的不同模型中进行验证。利用光学数据进行数据同化。使用国际参考电离层模型（IRI）创建一个模拟环境，范围从80到1000km. b。通过集成模拟LEO卫星光学观测，“三尖”海军研究实验室式仪器。c.创建算法，将LEO观测“合并”到IRI的不同模型中进行验证。3. GNSS与光学数据相结合的数据同化。融合GNSS和光学同化的能力，以达到更高的精度。每个目标的输出是卫星绕地球飞行时电子密度随时间变化的三维地图。目标2和目标3将各自形成独立的论文。研究的好处：该博士学位由工程与物理科学研究委员会（EPSRC）和国防科学与技术实验室（DSTL）赞助。主要受益者是DSTL，他们对预测电离层动态以预测和减轻电离层影响具有特殊兴趣。这适用于实时系统操作和任务规划目的的预测。EPSRC对工程、信息和通信技术、数学科学、物理科学、数字经济和英国各地的创新感兴趣。在定位和定时应用方面的商业部门对这项工作有广泛的兴趣。确保资金相关性：这项工作由DSTL部分资助，作为iCASE奖励的一部分。这建立在DSTL和巴斯大学在空间天气领域工作的现有关系的基础上。有定期的交互来确保项目过程中的相关性。这包括每月的进度更新，以及更具描述性的季度报告。这两者都要遵循与DSTL商定的格式。

Earth's ionosphere affects radio propagation, and is of interest to communication, navigation, and surveillance systems. The research team at Bath have conducted extensive research into ionospheric data assimilation using ground & space-based observation. However, there are new opportunities to undertake a high-resolution ionospheric assimilation imaging project using observations from closely spaced low-Earth orbit satellites. These satellites, named CIRCE, will have 2 key instruments onboard: A GNSS receiver (TOPCAT), and an optical imager (Tri-tip). This PhD aims to overcome the challenge of imaging through developing data assimilative algorithms, and includes research of how to combine GNSS and Optical data into a uniform output. Aims and objectives:The deliverables of the project come as three key milestones.1. Data assimilation using GNSS data.a. Create a simulation environment using the International Reference Ionosphere model, IRI, from 80 to 1000km. b. Integrate through to simulate LEO satellite to GNSS satellite observations.c. Create algorithms to 'merge' the LEO observation into a different model to IRI for verification.2. Data assimilation using Optical data.a. Create a simulation environment using the International Reference Ionosphere model, IRI, from 80 to 1000km. b. Integrate through to simulate LEO satellite optical observations, 'Tri-Tip' Naval Research Laboratory-like instrument. c. Create algorithms to 'merge' the LEO observation into a different model to IRI for verification. 3. Data assimilation of a combination of GNSS and Optical data.a. Merge the capabilities of GNSS and Optical assimilation, with the aim of achieving a higher degree of accuracy.The output of each aim is a 3D time-evolving map of electron density as the satellite flies around the Earth. Aims 2 and 3 are expected to each form their own independent paper. Benefits of the research:This PhD is sponsored by the Engineering and Physical Sciences Research Council (EPSRC) and the Defence Science and Technology Laboratory (DSTL). The primary beneficiary is the DSTL, who have specific interests in forecasting the dynamics of the ionosphere for the prediction and mitigation of ionospheric effects. This applies to real time systems operations, and forecasting for mission planning purposes. The EPSRC has interests in engineering, Information and communication technologies, mathematical sciences, physical sciences, the digital economy, and innovation across the UK. There is a wide area of interest in this work from the commercial sector working in applications of positioning and timing.Ensuring funding Relevance:This work is part-funded by the DSTL as part of an iCASE award. This builds on existing relationships established between the DSTL and the University of Bath working in the space weather area. There are regular interactions to ensure relevance over the course of the project. This includes monthly progress updates, as well as more descriptive quarterly reports. Both of these are to follow an agreed upon format with the DSTL.