Improving the Angular Resolution of a Scanning Radar with Imperfectly Known Antenna Patterns

Abstract

This paper proposes a technique able to improve the angular resolution of a scanning radar, i.e. to discriminate the responses of objects located in the main beam of the radar scan, in the extreme case of an unknown antenna pattern. The blind estimation of the effective antenna scattering features is conducted in the angular spectral domain, exploiting the principle of circular convolution. Angular resolution improvement may be achieved through numerous techniques, and a well-known deconvolution approach, called the Richardson-Lucy iterative techniques, is used in this study for illustration purposes. The effectiveness of the proposed approach is demonstrated using both simulated signals and real acquisitions performed using an X-Band maritime navigation radar designed within the Diades Marine company. Results indicate that applying deconvolution techniques using erroneous antenna diagrams leads to numerous false alarms and globally poor discrimination performance. The proposed technique permits to overcome this limitation and reaches comparable to the ones obtained in the case of an ideal antenna diaaram.