Focus-before-detection radar signal processing: Part II-recent developments

Due to high-speed, highly maneuvering, and weak targets as well as strong clutter and jamming, it is known that the environment of modern radar becomes increasingly challenging [1-7]. To deal with the challenges, focus-before-detection (FBD) [8-15] has been introduced in the first article [1] of this two-article series. As some of the typical FBD methods, Radon-Fourier transform (RFT) and generalized RFT (GRFT) originally proposed in [8, 9] have briefly introduced in [1] for coherent integration of a long time on target (TOT) to focus the energy of a target in parameter space with arbitrary parametric motion. That is, the motion is modeled with a finite number of translational and rotational motion parameters, such as velocity, acceleration, and also jerk. The FBD methods can overcome the effects of across range cells (ARC), across Doppler cells (ADC), and even across beamwidths (ABW) in a long TOT. As a result, by combining accurate environment sensing from echoes and effective resource management for optimization, the proposed FBD-based methods can effectively improve target detection and parameter estimation without changing system parameters in a complicated environment.