Bistatic FDA-MIMO radar space-time adaptive processing

Abstract

Detection of moving targets under range-dependent clutter background is a challenging task in conventional bistatic space-time adaptive processing (STAP) radar. It is more intractable in the presence of range ambiguity, which also results in parameter estimation ambiguities. To tackle these issues, this paper proposes a novel framework of bistatic multiple-input multiple-output (MIMO) STAP radar with frequency diverse array (FDA) as the transmit array. The FDA employs a micro frequency increment across the array elements. Therefore, it is capable of providing additional degrees-of-freedom (DOFs) in range domain in the transmit end. After combining the DOFs in transmit, receive and pulse dimensions, the clutter or target of bistatic FDA-MIMO radar possesses the following properties: (i) for a particular range region, the clutter ridges of all range bins are located in a common plane of the three-dimensional (3D) space. (ii) By properly designing the frequency increment of FDA, the clutter ridges from different range regions are located in distinct 3D planes and thus are discriminable in 3D space. (iii) As long as the sum of the target radial velocities relative to the transmitter and the receiver is unequal to zero, the target will not be located in these clutter planes. By exploiting these new properties, a 3D localized space-time-range adaptive processing (STRAP) approach is presented to realize clutter suppression. It evidently reduces the computational complexity and the requirement for the amount of training data. Several numerical examples are provided to demonstrate the superiority of the proposed technique over the existing techniques.