基于双曲线调频波形的高速目标成像

Imaging of high speed targets based on hyperbolic frequency modulated waveform

高速运动目标下,雷达回波的尺度调制效应不可忽略,线性调频(LFM)波形的常规脉压性能恶化,造成成像散焦。双曲线调频(HFM)波形作为一种多普勒不变性波形,在高速目标成像中具有重要应用价值。本文建立高速运动目标回波模型,基于瞬时频率分析比较线性调频波形与双曲线调频波形面对高速运动目标的成像效果,重点分析双曲线调频波形的系统实现、成像特点和应用优势,并与线性调频波形成像进行比较,数值仿真实验结果验证了该方法的有效性。

When the relative velocity between radar and targets is really high,the scale modulation effect of radar echoes is not negligible.The pulse compression of received Linear Frequency Modulated(LFM)echoes is degraded significantly,which causes defocused image of radar systems.Hyperbolic Frequency Modulated(HFM)waveform is of the characteristic of Doppler invariance,and it has a high application value in the imaging of high speed targets.First,the received echoes of high speed moving targets are modeled and the imaging results are compared between LFM and HFM by instantaneous frequency analysis.Then,the system implementation,imaging characteristics and application superiority of HFM echoes from high speed targets are analyzed in detail,and compared with that of LFM method.Finally,numerical results validate the effectiveness of the proposed method.