滑窗式线性调频及衍生多相码旁瓣抑制滤波器

线性调频波形由于多普勒性能突出 ,一直是一种在雷达中具有广泛应用的脉冲压缩波形 ,但是线性调频的旁瓣不够理想。对线性调频旁瓣结构进行了理论分析 ,指出其主瓣附近旁瓣所具有的逐点倒相特性 ,并据此提出 3点滑窗旁瓣抑制滤波器 ,理论分析及仿真计算表明 ,3点滑窗滤波可以通过灵活的改变参数 ,达到不同的脉压要求 ,信噪比损失大约在 1d B左右 ,而且基本不随多普勒频率增长而变化。该滤波器同样适用于线性调频波形衍生的多相码 (P3/ P4)旁瓣抑制

Slide window sidelobe suppression filter for LFM and LFM derived polyphase coded waveforms

The linear Frequency Modulation (FM) waveform has been widely used in radar applicat ions because of its excellent Doppler performance, but the sidelobe level of its autocorrelation function is far from satisfactory. A theoretical analysis of the structure of the sidelobes of the linear FM signal autocorrelation function is presented. The phase of the sidelobes near the mainlobe of the linear FM autocorrelation function appears to change by π from one bin to another. A new sidelobe suppression filter structured as a 3 points sliding-window is then presented. Theoretical analysis and computer simulations show that through altering a parameter balance can be achieved among low sidelobes, low range resolution loss and low mismatch loss. The output SNR loss is around 1dB and the degradation introduced by increa sing Doppler frequency is negligible. The sidelobe suppression filter also works for the LFM derived polyphase coded waveforms, the P3/P4 codes.