主动声呐恒包络波形设计及其性能分析

为主动声呐设计恒包络的伪随机编码MSK调制波形。通过分析MSK信号表达式，得到波形的复包络信号。使用遗传算法优化伪随机序列，降低波形的自相关旁瓣，可减小声呐的虚警概率。通过优化复包络信号的自相关函数旁瓣值和互相关函数值，得到自相关性能和正交性能优良的恒包络波形，可以缓解多部声呐间的同频干扰。通过仿真分析波形的模糊度图，波形具有良好的频率分辨率和距离分辨率，可以取代峰均比过高的编码调相信号，满足主动声呐对运动目标的探测需求。

Constant envelop waveforms design and performance analysis for active sonar

Constant envelop waveforms modulated by pseudo random codes and Minimum Shift Keying (MSK) method were designed for active sonar. The complex envelop signals were obtained, after the expression of MSK signals was analyzed. The pseudo random codes optimized by genetic algorithm can reduce the autocorrelation sidelobe values of waveforms, and reduce the false alarm probability of active sonar. Constant envelop waveforms with good autocorrelation and orthogonality performances can be obtained, by optimizing the autocorrelation sidelobe values and cross-correlation values of complex envelope signals, which can alleviate interference between multiple active sonars. Ambiguity function shows that the designed waveforms has good frequency resolution and range resolution, which means that designed MSK waveforms can replace phase-modulated signals with high peak-to-average power ratio, and can be used for active sonar detecting moving targets.