Target detection and tracking via sparsity-promoting Tikhonov regularization

We discuss the utilization of sparsity-promoting regularization within the SIFTER target detection capability for OTH radar. SIFTER combines ionospheric modeling and ray tracing to detect small-RCS targets in noise and clutter. The SIFTER solution is interpreted as the distribution of backscatter cross section in ground coordinates (scattering surface). Solutions are obtained by solving the inverse problem with Tikhonov regularization. The utilization of concepts of sparsity-promoting regularization with fractional norms helps to combine multimode target returns into an single enhanced peak on the scattering surface, the position of which provides a high-fidelity estimate of target geolocation.