MIMO雷达OFDM-LFM波形设计与实现

由于MIMO雷达发射相互正交的波形,因此正交波形设计是MIMO雷达实现的关键问题。针对MIMO雷达发射波形正交的特点,介绍了正交频分复用线性调频波形(OFDM-LFM)的设计原理。提出了一种正交频分线性调频波形产生的实现方案,该方案通过并行发射多路频分的线性调频信号形成OFDM-LFM波形。设计了一种由主控计算机、波形控制模块和数字中频合成模块构成的OFDM-LFM波形产生器。给出了基于AD9910数字斜坡调制方式产生单通道线性调频信号的方法和OSK功能产生多通道线性调频脉冲信号的方法,并对单通道线性调频信号线性度进行了分析。最后给出了其中两通道LFM信号频谱和一通道线性调频脉冲信号的时域波形的测试结果,验证了方案的正确性和可行性。

Design for MIMO Radar and Implementation of OFDM-LFM Waveform

Waveform design is crucial for MIMO radar that transmits mutually orthogonal waveforms. Based on the characteristics of transmitted orthogonal waveforms, the design principles of the orthogonal fre- quency division multiplexing linear frequency modulation（OFDM-LFM） signals are introduced. In this paper a new realization scheme is presented where multi-channel frequency division linear frequency modulation sig- nals are used to generate OFDM-LFM signals. We design a waveform generator composed of a host comput- er, a waveform control module, and a digital intermediate frequency synthesis module. The method for forming single-channel linear frequency modulation signal based on the digital ramp modulation mode of AD9910 and the method for forming multi-channel chirp signal based on the OSK function of AD9910 are in- troduced and the linearity of the single-channel LFM signal is analyzed. Finally, the experimental results of the two-channel LFM signal spectrum and the time domain waveform of one channel chirp signal are presen- ted to verify the correctness and feasibility of the method.