GPR noise immunity evaluation using polarization-matched spectral expansion

Abstract GPR performance optimization in complex environments requires a consideration of evaluating the noise immunity of polarization matching based spectrum expansion methods. This study investigates the polarization matching characteristics in a microwave chamber, normal, and extreme environments, coupled with the effects of spectral expansion on target responses and noise distribution. The results demonstrate the following: (1) With noise power fixed at –80 dBm, multipath interference mainly increases phase error, while amplitude remains stable, ensuring robust polarization matching if deviation angles are kept small. (2) Spectral expansion significantly enhances noise immunity by widening the signal bandwidth. When the maximum frequency increases from 2 GHz to 7 GHz, the SNR improves by 8.3 dB, confirming that broader frequency bandwidth distribution effectively suppresses local noise. This study provides a theoretical framework for optimizing GPR system parameters in multipath interference environments, quantifying polarization deviation tolerance (polarization error threshold of 30°) and spectral bandwidth selection criteria (≥5 GHz), offering design guidelines for engineering applications in complex scenarios.