Dual Circularly Polarized GNSS-Reflectometry for Remote Sensing of Land and Sea Surfaces
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
University of Oulu
Topic of the dissertation
Dual Circularly Polarized GNSS-Reflectometry for Remote Sensing of Land and Sea Surfaces
Doctoral candidate
Master of Science (Technology) Ankit Regmi
Faculty and unit
University of Oulu Graduate School, Faculty of Information Technology and Electrical Engineering, Centre for Wireless Communication-Radio Technologies (CWC-RT)
Subject of study
Communications Engineering
Opponent
Professor Rüdiger Haas, Chalmers University of Technology
Custos
Docent Marko E. Leinonen, University of Oulu
Observations of Sea and Land surfaces by reflected GPS signals.
Remote sensing of the environment is crucial to better observe the effects of climate change. This thesis presents the analysis of reflected Global Navigation Satellite System (GNSS) signals for remote sensing of land and sea surfaces. The utilization of GNSS signals reflected from different Earth surfaces allows the investigation of important surface parameters such as the sea level, sea-ice thickness, soil moisture, etc., with the method known as GNSS-Reflectometry (GNSS-R). In this thesis, a cost-effective GNSS-R system was developed to collect direct and reflected GNSS signals for characterization of various Earth surfaces.
GNSS-R measurement campaigns conducted during this thesis investigated surface properties in different seasons and surface conditions. Sea ice thickness was estimated from the total freeboard, which was derived from the difference between the sea level bias calculated using GNSS-R and the sea level data from the Finnish Meteorological Institute. The signatures of penetration of the GNSS signals through the sea ice in received GNSS data enabled characterization of sea ice thickness. The statistics of the received GNSS data showed a correlation with the wind speed observations over the open sea. The relative permittivity of the open sea and land was measured by utilizing the change in electromagnetic wave polarization of reflected GNSS signals. The practicality of performing dynamic measurements using the developed dual circularly polarized GNSS-R system was tested onboard a drone for different remote sensing applications.
The developed system and the GNSS polarimetric analysis provide important tools for observations of our changing environment.
GNSS-R measurement campaigns conducted during this thesis investigated surface properties in different seasons and surface conditions. Sea ice thickness was estimated from the total freeboard, which was derived from the difference between the sea level bias calculated using GNSS-R and the sea level data from the Finnish Meteorological Institute. The signatures of penetration of the GNSS signals through the sea ice in received GNSS data enabled characterization of sea ice thickness. The statistics of the received GNSS data showed a correlation with the wind speed observations over the open sea. The relative permittivity of the open sea and land was measured by utilizing the change in electromagnetic wave polarization of reflected GNSS signals. The practicality of performing dynamic measurements using the developed dual circularly polarized GNSS-R system was tested onboard a drone for different remote sensing applications.
The developed system and the GNSS polarimetric analysis provide important tools for observations of our changing environment.
Last updated: 7.3.2025