Coherent integration with null constraint on clutter spectrum for pulse Doppler radar

In this paper, the null constrained coherent integration (NCCI) is proposed to improve detectability of the slow moving or maneuvering target for pulse Doppler radar. The projection matrix for clutter mitigation is predetermined based on clutter spectrum shape and the required clutter attenuation. In the real time processing, received clutter is mitigated by applying the projection matrix, then a target signal is coherently integrated by DFT or FFT. The process without adaptive processing relaxes the computational complexity and burden compared to the optimum Doppler filter. By computer simulation, the proposed method shows higher magnitude response around zero Doppler and wider flatten magnitude response in the passband compared with MTI followed by coherent integration.