Space Science Seminar: Imaging Earth’s High Latitude Ionosphere using GNSS signals

Dr Joe Kinrade, Department of Physics, Lancaster University

Wednesday 14 October 2015, 1400-1500
Cavendish Colloquium Room

Radio signals from Global Navigation Satellite Systems (GNSS) are delayed by the Earth’s ionosphere as they travel from satellite to receivers on the ground. Using measurements of these delays from a ground receiver network, it is possible through tomographic imaging to reconstruct images of the ionospheric electron content. Wide area images of the ionosphere are useful in profiling the plasma response to space weather events and geomagnetic storms, particularly at high latitudes where magnetic field lines channel energy into the atmosphere from the near-Earth space environment. Tomography offers a novel view of the ionosphere’s more dynamic and unpredictable morphology.

Sporadic geomagnetic events drive the production of turbulent, fast moving electron density structures in the ionosphere at auroral and polar latitudes, which refract and diffract travelling radio signals. Manifesting at a user receiver as a local interference field, this effect, known as scintillation, can severely affect sensitive GNSS positioning and timing applications such as ocean-floor drilling or glacial motion surveys. Modified low phase-noise receivers can measure these satellite signal fluctuations at high time resolution, allowing the remote sensing of ionospheric structures with the free-to-use signals of GNSS.

This seminar introduces the application of GNSS tomography to ionospheric imaging at high latitudes, and the effects of plasma structures on GNSS signals. Joe led an expedition to Antarctica to deploy a network of atmospheric monitoring stations across the continent, and the seminar will also highlight his fieldwork experiences and the challenges of remote deployment in polar regions.