Improved Range-Doppler Algorithm for SAR Imaging Based on Phase-Coded Signals

Abstract

Traditional synthetic aperture radar (SAR) imaging typically employs linear frequency modulation (LFM) signals, but such signals have simple structures, are vulnerable to interference, and often require increased bandwidth to improve range resolution, resulting in low spectral efficiency. In complex electromagnetic environments requiring multiple target balancing, this approach may waste bandwidth resources. This research proposes an improved range-Doppler algorithm imaging scheme using phase-coded signals for SAR echo signals. The study applies dual quadrature phase-shift keying (QPSK) processing to LFM signals and further enhances system performance through adaptive phase coding strategies, improved range cell migration correction methods, and novel Doppler compensation mechanisms. The improved algorithm has been extensively tested in simulated environments, demonstrating significant enhancements in anti-interference capability, imaging quality, and Doppler tolerance, with peak sidelobe ratio (PSLR) improvement of approximately 22% and integrated sidelobe ratio (ISLR) improvement of approximately 22%. This method has important value in applications requiring high-quality imaging and anti-interference capabilities, such as military reconnaissance and disaster monitoring.