Two-dimensional filter bank design for velocity estimation in Forward Scatter Radar configuration

The focus of this paper is on the estimation of the velocity of moving targets with a Forward Scatter Radar system. To this aim a two-dimensional filter bank is proposed with the generic filter impulse response depending on the target electrical size and on the target trajectory that are a priori unknown. In order to limit the computational load required by the bank for practical applications, a two-step processing is proposed: in the first step a rough estimate of the target cross-baseline velocity component is obtained by applying the Radon transform to the spectrogram of the acquired signal while in the second step the bank is exploited to refine the velocity estimation provided by the previous step and also to provide a rough estimation of the target electrical size. The performance of the proposed approach is analyzed against synthetic data under different case studies such as different motion directions, baseline crossing points and different target dimensions. Finally results obtained by applying the proposed processing to FM-based passive FSR experimental data are shown demonstrating the effectiveness of the considered approach.