MIMO雷达正交频分相位编码波形优化

摘要

正交频分相位编码(Orthogonal Frequency Division-Phase Coded,OFD-PC)信号是多输入多输出(Multiple Input Multiple Output,MIMO)雷达中的一种重要波形.为进一步提高该波形对目标的探测能力,在分析OFD-PC空域合成信号脉压特性的基础上,提出了一种降低其距离旁瓣的波形优化方法.一方面,通过优化选取自相关性能优良的相位编码序列来直接降低空域合成信号的距离旁瓣;另一方面,通过随机离散化OFD-PC信号中的载频间隔,构建一种非均匀间隔的OFD-PC信号形式,进一步改善其距离旁瓣特性.为合理平衡波形的正交性能和自相关性能,建立空时联合优化模型,并采用序列二次规划法求解.仿真结果表明,该方法能在获取近似全向发射功率方向图的同时,降低信号自相关距离旁瓣;所优化设计的波形比传统OFD-PC波形具备更优的脉冲压缩性能.%Orthogonal frequency division phase-coded(OFD-PC)signal is an important signal in multi-ple-input-multiple-output(MIMO)radar.To improve the target detection ability with this waveform,the pulse compression property of the spatial synthesized OFD-PC signal is analyzed,and a waveform optimiza-tion method to reduce the range sidelobe is proposed.On one hand,selecting the code sequence with good autocorrelation performance can reduce the sidelobe level directly.On the other hand,building OFD-PC sig-nal with non-uniform frequency interval by randomly discretizing the carrier frequency steps can improve the sidelobe property further.To balance the waveform orthogonality and autocorrelation properties reasonably, a joint temporal-spatial optimization model is established,and the sequential quadratic programming method is utilized to solve the optimization problem.Simulations validate that the autocorrelation sidelobes of the optimized waveform are reduced while the transmitted power beam pattern approaches omnidirectionality, which reveals the superiority of the optimized OFD-PC waveform over the traditional OFD-PC waveform.