Frequency Diversity in Low-Altitude Target DOA Estimation

In the presence of sea-surface multipath, multipath distortion has been a challenge problem for low elevation target's direction of arrival (DOA) estimation in monopulse radar. Frequency diversity has been explored as a technique in communication to resist multipath and propagation effects. In this paper, approach to integrating frequency diversity into the DOA estimation, that is suitable for sea-surface multipath environment, is proposed. In particular, principles that seek for appropriate frequency selection with higher accuracy of angle measurement, is investigated. Compared with the general circumstances without frequency diversity, the advantage of this method in DOA estimation accuracy for low elevation targets is validated from a theoretical point of view as well as from numerical simulations.