Improving Temporal Resolution and Spatial Coverage of SuperDARN Radars using Wide Transmission Beams and Multistatic Operation
Date
2025-04-29
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-2208-1553
Type
Thesis
Degree Level
Masters
Abstract
The recently developed Borealis digital radar system for Super Dual Auroral Radar Network (SuperDARN) radars has the potential to vastly improved the resolution of retrieved ionospheric data. The standard common operating mode for SuperDARN radars scans sequentially through 16 or 24 beam directions over the course of one minute. The data from each radar are combined to generate maps of plasma drift in each hemisphere, from which the global ionospheric plasma convection pattern and hemispheric electric potentials are estimated. The network has been operational for over 30 years, providing an unparalleled historic dataset. The work presented in this thesis improves upon the standard common operating mode through increasing temporal resolution and extending spatial coverage of SuperDARN radars, enabling high resolution data collection with the potential to increase data rates by two orders of magnitude.
The first improvement to the common operating mode was achieved through broadening the transmitter beam pattern to illuminate the entire radar field of view at once, thereby enabling simultaneous sampling of all receiver beam directions. Broadening the beam decreased the peak directivity and increased the relative side lobe level. Given the high signal-to-noise ratio of signals received by SuperDARN radars, the decrease in peak directivity only marginally impacts data quality. The increased side lobe levels have been remedied through applying an amplitude taper to individual antenna signals during beamforming. The second improvement to the common operating mode is achieved through multistatic radar operation. Implementation of pulse sequence synchronization between different sites provided the necessary timing stability for multistatic operations. A geolocation model for single-hop ionospheric scatter of HF waves at high latitudes was derived for bistatic radars, and shown to converge in the case of a monostatic radar.
The decrease in scan duration achieved by transmitter beam spoiling increases data production sixteen-fold, increasing temporal resolution without sacrificing spatial coverage. A full-day experiment utilizing a multistatic configuration with one transmitting radar and three receiving radars yielded a 114% increase in spatial coverage over single-site monostatic operation, plus additional independent measurements in 81% of single-site scattering locations.
The new operating modes are a significant improvement to SuperDARN radar capabilities. To further advance this work, transmitter calibration, transmitted power modulation, optimization of beam patterns, interferometry, and multi-hop multistatic geolocation could be explored.
Description
Keywords
SuperDARN, radar, phased array, multistatic, beam spoiling, phased-array synthesis, genetic algorithm,
Citation
Degree
Master of Science (M.Sc.)
Department
Physics and Engineering Physics
Program
Physics