Subarray-Based Frequency Diverse Array for Target Range-Angle Localization With Monopulse Processing

Frequency diverse array (FDA) can offer new degrees-of-freedom, but the target localization of basic FDA is fundamentally limited by the range-angle-coupled and range-periodic peaks of beampattern. In this paper, we propose a localization system with the combination of subarray-based FDA and full-band FDA, as the transmitter and the receiver, respectively. The transmit and receive beampatterns are both decoupled in range and angle domains. Target range-angle localization is achieved by two steps. First, using the outputs of subarrays, we solve the range ambiguity and obtain a coarse location. Second, the monopulse processing of range-angle localization is developed for the proposed system by taking the coarse location as the receiving beam pointing. The localization performance is also analyzed in Cramér-Rao lower bound, computational complexity, and output signal to interference-plus-noise ratio. Several simulation results demonstrate that unambiguous target range-angle localization can be achieved with a low computational cost by the proposed method.