一种基于非线性调频信号和空域编码的FDA雷达波形设计方法

A Waveform Design Method Based on Nonlinear Frequency Modulation and Space-coding for Coherent Frequency Diverse Array Radar

频率分集阵列(FDA)雷达通过在不同发射阵元间引入微小的载频增量,实现发射方向图在脉冲持续时间内对大尺度空域的均匀连续扫描。然而FDA雷达方向图主瓣的扫描特性,使得其在一个方位角度位置的波束驻留时间缩短,积累带宽减小,从而降低其距离分辨率。针对上述问题该文提出了一种空时域联合的FDA雷达波形设计方法,通过引入阵元间的空域相位编码显著改善了相干FDA雷达的距离分辨率,同时在时域设计一种非线性调频波形获得了更低的距离旁瓣。该文从理论上分析了该方法的有效性,并通过仿真实验证明了该波形设计方法同时具有距离向高分辨和低峰值旁瓣比的优势,具有更好的一维距离向成像性能,并分析了其对高速运动目标的观测能力。

A Frequency Diverse Array(FDA) radar achieves the uniform coverage of a large-scale airspace within a pulse duration by introducing a designed carrier frequency increment between adjacent transmitting elements. Unfortunately, the beam scanning property of an FDA radar leads to a reduction in dwell time at certain azimuth direction, which results in the deterioration of the range resolution. To solve this problem, we propose a novel coherent FDA radar waveform in the space-time domain, in which spatial phase encoding is introduced between transmitting elements to significantly improve the range resolution of a coherent FDA radar. A nonlinear frequency modulation signal is also used in the time domain to obtain a low-range Peak to SideLobe Ratio(PSLR). Simulation results verify that the proposed FDA radar waveform design realizes both a low PSLR and high range resolution. Finally, we analyze the Doppler sensitivity of our proposed method for the observation of high-speed moving targets.