Radwan N. K. Sharif

Topic

Monitoring Earth Using the Software Defined Radio (SDR) Earth Imager

Department of Mechanical Engineering

Date & location

• Tuesday, February 13, 2024

• 9:00 A.M.

• Virtual Defence

Reviewers

Supervisory Committee

• Dr. Rodney Herring, Department of Mechanical Engineering, University of Victoria (Supervisor)

• Dr. Brad Buckham, Department of Mechanical Engineering, UVic (Member)

• Dr. Geoffrey Steeves, Department of Physics and Astronomy, (Outside Member)

• Dr. Peter Driessen, Department of Electrical and Computer Engineering, UVic (Outside Member) 

External Examiner

• Dr. Jann-Yeng (Tiger) Liu, Space Science and Engineering, National Central University 

Chair of Oral Examination

• Dr. Tim Hopper, School of Exercise Science, Physical and Health Education, UVic

   

Abstract

The ionosphere, which is the highest region of Earth's atmosphere, contains waves created from both space and Earth disturbances. The ionosphere is considered the largest sensor on Earth and has been the subject of study since the 1920s, primarily through the use of ionosondes. A Software Defined Radio (SDR) Earth Imager has been devised to obtain information about these Earth disturbances. This research is divided into four stages: 1) engineering of the SDR Earth Atmosphere Imager, 2) imaging of waves that exist within the ionosphere, 3) determining the location of the earth disturbance that created the waves, and 4) measuring the power of the ionospheric waves.

The SDR Earth Imager device functions similarly to a camera by utilizing an antenna array to create images of the ionosphere and its waves. The radio wave, i.e., the carrier wave of the ionosphere information, is transmitted up through the atmosphere at a near-vertical incidence from the Earth's surface. It reflects off the ionosphere back down to the Earth's surface, where it is detected by an antenna array to produce a phase image of the ionosphere.

The proof of concept of the SDR Earth Imager occurred at the University of Victoria, Victoria, BC, Canada, and was initially constructed at the Dominion Radio Astrophysical Observatory (DRAO), Penticton, BC, Canada. From the DRAO data analysis, two types of waves were found: one with a constant frequency, possibly originating from power losses in transmission lines, and another with a single sharp spike, potentially caused by earthquakes or lightning.

Further experiments at the University of New Mexico, utilizing Long Wavelength Array (LWA-1 and LWA-SV) antennae arrays, served as a high-resolution radio wave camera. The datasets from the LWA-1 and LWA-SV sites provided results showing the wavevector directions of one set of ionospheric waves, i.e., the strongest sets of waves, which have a spatial frequency of 0.06 cycle/m. The wavevectors were used to identify the location of the generation of the ionospheric waves and, thus, the likely source of the disturbance. This analysis revealed that the most likely source of ionospheric disturbance was the power generators and their transmission lines in and around Albuquerque, which is the highest electricity consumption city in the identified source area of the measured disturbances.

This Ph.D. research thesis shows a correlation between the waves in the ionization layer and Earth's disturbing events, including man-made disturbances like nuclear tests, as well as the electromagnetic radiation emitted by power lines and electrical grids, which generate waves within the ionosphere that generate waves within the ionosphere. Further, this research illustrated how the phase image, not the amplitude image, determined from Fourier analysis is critical to characterizing these waves. The phase image enables the characterization of these waves by providing information about their phase shifts, frequencies, and wave vectors.

This research demonstrates a clear relationship between waves within the ionosphere and disturbing events occurring on Earth. One significant finding of this dissertation is the deduction that all power generated and consumed by humans is not completely dissipated but rather transformed and captured by the Earth's ionosphere. This fact may assist climate modelers in gaining a better understanding of climate change.