Ionospheric data assimilation using satellite observations

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.