Residual-Feedback-Aware Range-Profile Sidelobe Suppression for Stepped-Frequency Radar

Abstract

Under locally strong ground clutter, strong clutter residuals and range sidelobes in stepped-frequency radar may mask weak scattering points, produce false peaks, and degrade range-profile quality when detecting low, slow, and small UAVs. APC-RMMSE constructs the covariance matrix from power estimates of the current iterative range profile. When highamplitude non-target components dominate, the estimated power may deviate from the true scattering power, contaminating the covariance matrix and causing excessive suppression of weaktarget responses. A residual-feedback-aware adaptive pulse compression method (RF-AAPC) is proposed to address this problem. After the first APC-RMMSE update, a candidate protection region is determined from the amplitude and neighborhood structure of the range profile and retained during subsequent iterations to preserve potential target scattering responses. For range cells outside the protection region, differences between two successive iterative outputs are recursively smoothed, and the resulting residuals are used to correct the range-cell power estimates. Strong-clutter residuals are also incorporated into the covariance reconstruction as interference, reducing their influence on filter updates. Simulation and measured-data results show that, compared with APC-RMMSE, RF-AAPC further suppresses range sidelobes and background fluctuations, reduces false peaks, and improves the visibility of weak targets under locally strong ground clutter.