由传统DBF 方法得到分布式MIMO 雷达S 曲线的线性区很窄，不利于单脉冲测角。基于无栅瓣的分布式MIMO 雷达发射-接收联合波束方向图提出利用回波信号的绝对值相加减得到和、差波束，该方法可以获得理想的零值深度，差波束主瓣能被和波束主瓣包围，有效扩展了S 曲线的线性区。针对切向速度较高的目标进行单脉冲测角的数值仿真。在信噪比大于−15 dB 时，所提方法精度优于传统方法。在信噪比等于−15 dB 时，取绝对值之前进行相参积累，表明所提方法精度接近传统方法。
The linear zone of the S-curve, which is formed with the digital beamforming (DBF) method, is extremely narrow for monopulse angle measurements with distributed Multiple-Input and Multiple-Output (MIMO) radar. Based on the transmitting-receiving beam pattern without gratelobe, the DBF method is proposed to form the ΣΔ-beam by using the absolute value of the echo signal. The ideal null depth can be achieved and the linear zone of the S-curve is expanded because the main lobe of the Δ-beam is enveloped by the Σ-beam. The monopulse angle for a target with high angle velocity was estimated. When the Signal-to-Noise Ratio (SNR) was higher than −15 dB , the accuracy of the proposed method was better than that of conventional methods. When the SNR was equal to −15 dB , the accuracy of the proposed method was similar to conventional methods that use coherent integration before taking the absolute value of the echo signal.
