Abstract

Frequency diverse array (FDA) radar applies a tiny frequency offset across its adjacent transmitting array elements to generate a range-angle-dependent beampattern. The increased degrees-of-freedom (DOFs) in range domain can help improve the performance of radar in target detection, localization, and clutter suppression.

Passive radar utilizes uncontrollable external signal as illuminator, which makes it difficult to apply traditional frequency diverse process method. However, the third-party illuminator such as Orthogonal Frequency Division Multiplexing (OFDM) signal usually consists of several closely spaced modulated carriers, and it has been widely selected as the illuminator for passive radar in recent years.

Considering the orthogonality between even separated subcarriers, we propose a new frequency diverse process method by extracting and processing each subcarrier of received data independently and attempt to provide a range-angle dependent beampattern for OFDM passive radar. Numerical results and real data analyses verify the superiority of frequency diversity process on the received data of OFDM passive radar.