针对混沌信号应用于雷达系统中由于具有较高的峰均功率比(PRMS)容易被远距离的敌方电子侦察设备截获的问题, 提出了一种改进的混沌序列调制的雷达信号。基于Lorenz系统的混沌信号具有初值敏感、随机性强、宽频谱等优点, 可取代普通的伪随机序列应用于低截获概率雷达信号设计中。然而由于Lorenz混沌信号具有较高的PRMS, 容易被敌方截获。通过对Lorenz混沌信号引入一个与其实部信号功率交错排列的虚部信号, 并通过映射得到一种改进的Lorenz混沌信号, 降低信号的峰均功率比。理论分析和仿真结果表明, 改进的Lorenz混沌信号PRMS得到降低, 信号的低截获性能得到进一步改善。

The chaotic signal applied in radar system can be easily intercepted by electronic reconnaissance equipment of the distant enemy in modern electronic war due to its high PeaktoRMS ratio (PRMS).To solve the problem,an improved radar signal modulated by chaotic sequence was presented.The Lorenz chaotic signal has good randomicity,a sensitive dependence on initial conditions and a wide spectrum,which can be used to substitute the existing pseudorandom sequence for the signal design of LPI radar.The Lorenz chaotic signal can be easily detected by the receiver of enemy because of its high PRMS,thus an improved signal was introduced by combining an imaginary component with a real component,and the two parts appeared in different time region.Additionally,a map was introduced in order to further reduce the PRMS,so that the LPI performance of signal was improved.The performance of the new signal was simulated and compared with the original Lorenz chaotic signal.The result showed that the PRMS of the improved Lorenz chaotic signal was reduced effectually,and its LPI performance can be improved.