Probing the ionosphere using radio signals

This project will involve evaluating the use of software defined radio (SDR) as a realistic tool for probing the ionosphere. Initially in the laboratory, and then utilising transmissions from the Defence Science & Technology Group (DST) Murray Bridge field site to evaluate the concept experimentally.

The ionosphere is a region of the atmosphere-space environment. It is a thick shell of electrons and ions surrounding the Earth, extending from a height of around 50 km to beyond 1000 km. The ionosphere supports propagation of high-frequency (HF) radio signals over long distances via refraction, allowing applications such as long-distance communications and over-the-horizon radar, such as those comprising Australia’s Defence surveillance system, the Jindalee Operational Radar Network (JORN). The ionosphere also affects global navigation satellite systems (GNSS), such as GPS signals, by reducing position accuracy through signal absorption, scintillation, Faraday rotation & decoherence.

Ionospheric sounders (or Ionosondes) are instruments which characterise the ionosphere by measuring the time delay of ionospherically propagated HF signals across a wide frequency range. Ionospheric sounder measurements are important for investigating the physical processes which give rise to ionospheric disturbances, wave phenomena and deviations from great-circle path propagation. They are also an important instrument for measuring the electron density profile of the ionosphere. They allow the development of ionospheric models for forecasting, now-casting and real-time operations.

Software defined radio (SDR) provides the potential for development of low-cost ionospheric sounder receivers. This may provide an economical means for increasing the number of deployable ionospheric sounder receivers, increasing the spatial and temporal fidelity of the ionospheric models and giving greater physical insight and understanding of ionospheric disturbance processes.


Tagged in Honours projects - Physics, Honours Projects - Trevor Harris, Honours in Physics subtheme - Space and atmospheric