An Adaptive Range-Angle-Doppler Processing Approach for FDA-MIMO Radar Using Three-Dimensional Localization

High pulse repetition frequency incurs range ambiguity in radar systems, which in turn results in clutter suppression performance degradation and parameter estimation ambiguities. To tackle this issue, this paper proposes an adaptive range-angle-Doppler processing approach with airborne frequency diverse array (FDA) for multiple-input multiple-output (MIMO) radar. The FDA employs a small frequency increment across array elements and introduces additional controllable degrees-of-freedom (DOFs) in range dimension in the transmit antenna. Thus, it is able to perform range-angle-Doppler processing by exploiting the DOFs in transmit, receive, and pulse dimensions in the FDA-MIMO radar. By properly designing the frequency increment of the FDA, the clutter spectra of different ambiguous range regions can be discriminable in the transmit-receive spatial domains. As a result, multiple beams are formed in the transmit spatial, receive spatial, and Doppler domains and clutters from different range regions can be suppressed. An enhanced three-dimensional localization technique is proposed for the case with severe range ambiguity problem, which evidently reduces the dimensions of the processor and efficiently suppresses clutter in practical applications. Several numerical examples are presented to verify the effectiveness of the proposed approach.