SOFTWARE-DEFINED COHERENT-ON-RECEIVE PROCESSING FOR MAGNETRON-BASED COMMERCIAL MARINE RADAR

Abstract

Commercial navigational marine radar systems are attractive for maritime and oceanographic use due to their high power and low cost. However, their magnetron-based transmitters generate random phase variations, and their receive subsystems are susceptible to intermediate frequency drift. This thesis develops a software-based coherent-on-receive signal processing framework that enables coherent Doppler processing on unmodified magnetron-based radar platforms. To resolve the random pulse-to-pulse phase variations, the study proposes two distinct phase correction algorithms: a Gradient Ascent optimization and a computationally efficient Phase Difference Averaging technique. The proposed algorithms are evaluated in comparison with an existing technique rooted in matched filtering principles. Furthermore, the research mitigates non-stationary intermediate frequency by utilizing the proposed power spectral density and template matching estimation techniques. The efficacy of the framework is rigorously tested through experimental data collections in radar environments, including stationary ground targets, dynamic platform motion, and true sea clutter. Experimental results confirm that signal processing algorithms can extract coherent Doppler information on moving targets, including unmanned aerial vehicles, helicopters, thrown projectiles, and birds, even when obscured by dominant environmental clutter. Ultimately, this work develops and validates advanced adaptive signal processing techniques that overcome the inherent hardware limitations of affordable marine radars, rendering them viable for advanced detection applications.