Pixel Based Shadow Profile Retrieval in Forward Scatter Radar Using Forward Scatter Shadow Ratio

The existing optimization method for target shadow profile retrieval in forward scatter radar using forward scatter shadow ratio (FSSR) can only retrieve rectangular strips aggregated in one dimension. As a result, it can only handle one target, rather than multiple targets. In this paper, a pixel based shadow profile retrieval approach is proposed, in which the target retrieval plane is divided into square pixels in two dimensions. A nonlinear least-square algorithm, combined with hard thresholding, is introduced to obtain binary values for all pixels. Unlike the strip based approach, this new method simplifies the analytical aspects by eliminating the imaginary error function from the nonlinear least-square algorithm. Instead, complex coefficients of the pixels are calculated once only and stored for use in the nonlinear least-square. Numerical results suggest that two receivers are sufficient to retrieve shadow profiles for a single target with various shapes and sizes. For fleets of targets, two or more receivers are typically required, with additional receivers further enhancing performance.