基于双曲调频的组合波形设计研究

Research on Combination Waveform Design Based on Hyperbolic Frequency Modulation

主动声呐通常采用的单频或调频波形时频耦合分辨能力弱,不利于混响背景下的信号检测与估计。先前工作表明,“V”和“W”形双曲调频(HFM)组合波形可以实现距离-速度高分辨和低混响输出,其中W-HFM波形还有效解决了V-HFM波形在多目标场景中的虚假目标问题,但是设计复杂、运算量大。为优化HFM组合波形的设计和应用,该文推导了HFM组合波形的峰脊线斜率表达式。一方面提出V-HFM波形的最小无虚警距离(MNFAD)指标,分析了其多目标适用性;另一方面以典型的W-HFM波形为例,提出了优化的波形设计方案,对工程应用具有指导意义。水池实验数据表明,HFM组合波形实现了距离-速度高分辨、混响输出降低5 dB以上,并且W-HFM波形还抑制了虚假目标干扰。

The single frequency or modulated frequency waveform employed in active Sound Navigation and Ranging(SONAR)systems yields inferior range or velocity resolution.This deficiency impairs signal detection and estimation in reverberation background.Previous work demonstrates that“V”and“W”type Hyperbolic Frequency Modulation(HFM)combination waveforms substantially enhance range–velocity resolution while simultaneously reducing reverberation.The W-HFM waveform serves as an effective solution to the false-target problem inherent in the V-HFM waveform when applied to multiple-target scenarios.However,the complex design and extensive computation required pose considerable challenges.Thus,the ridge slope equation of HFM combination waveforms is derived to optimize their design and application.Furthermore,the minimum no false alarm distance index of the V-HFM waveform is proposed,and its applicability in multipletarget scenarios is analyzed.Additionally,an optimized waveform design scheme is proposed,using the typical W-HFM waveform as an example,which can serve as a guide for engineering applications.Tank experimental data reveal that the HFM combination waveform achieves high range–velocity resolution,reverberation is reduced by more than 5 dB,and the W-HFM waveform suppresses false target interference.