Time-Range Focus-Before-Detect Method in Clutter Background

Abstract

The traditional coherent radar signal processing generally adopts the cascaded processing method of pulse compression and Radon-Fourier Transform (RFT) for a target moving across the range cell. However, the cascaded processing exhibits the following problems: first, during the energy integration of a high-speed target, problems including the offset of the target peak, even broadening of the main lobe, gain reduction and increases in the side lobes will occur; second, the lack of effective clutter suppression affects the detection of weak targets. Based on the multi-dimensional signal combination and clutter suppression, this paper proposes a Time-Range Focus-Before-Detect method (Adaptive-Pulse Compression Radon-Fourier Transform, A-PCRFT) in clutter background, which combines the pulse compression, RFT and adaptive clutter suppression. First, the method combines the two radar signal processing dimensions of intra-pulse time (fast time) and inter-pulse time (slow time). The two-dimensional steering vector corresponding to the high-speed target is introduced to compensate for the intra-pulse time and inter-pulse Doppler shifts; Then, the clutter covariance matrix before pulse compression is estimated based on the secondary data; Finally, the optimal filter weight vector is determined according to the clutter covariance matrix and the steering vector. This method can effectively suppress the clutter and focus the target energy simultaneously in the range-velocity space. Simulation results show that this method is superior to the cascaded method, which adopts the pulse compression and adaptive Radon–Fourier transform.

Keywords

• pulse compression
• radon-fourier transform (rft)
• adaptive clutter suppression
• time-range combination
• focus-before-detect (fbd)