An extended target signal integration method via mainlobe broadening

Abstract

To improve the detectability of extended targets, a novel mismatched filter is designed, which deliberately broadens the 3 dB mainlobe width (MW) of the output response. Similar to how narrowband radar accumulates target energy, this filter concentrates the energy of scattering centers into the same resolution unit. To achieve this, constraints on 3 dB MW, mismatched filter gain, and signal-to-noise ratio (SNR) are imposed on the mismatched filter, while the integration sidelobe level (ISL) is minimized as the figure of merit. To handle the resulting non-convex problem, a polynomial-time method based on sequential convex approximation (SCA) which slacks the non-convex constraint is proposed to decrease ISL. Numerical results demonstrate successful broadening of the 3 dB MW within a certain range, and efficient accumulation of extended target energy.