Continuous active sonar (CAS) waveforms provide an advantage over conventional pulsed active sonar (PAS) waveforms, which is, they can be processed to provide a higher target update rate through subpulse processing. Performance in reverberation limited conditions is particularly important in shallow water. This article compares the signal-to-reverberation ratio (SRR), echo level, and reverberation level of simultaneously transmitted linearly frequency modulated (LFM) PAS with an equal bandwidth LFM CAS waveforms processed with different CAS subpulse durations in a littoral environment. Data from an experimental sea trial showed that the LFM PAS waveform outperformed the full-band LFM CAS waveform in terms of SRR by 3.0 $\pm$ 2.1 dB. The SRR of the CAS waveform degraded by less than the expected 3 dB per halving of the subpulse bandwidth and duration. Energy spreading loss, which increases with bandwidth, was shown to be the dominant cause of the deviation from expected degradation rate. The detection performance of the full-band LFM CAS waveform was approximately equal to that of the LFM PAS waveform as measured by a receiver operating characteristic analysis.

中文翻译：

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线性调频连续有源声纳和脉冲有源声纳的信噪比比较

连续有源声纳（CAS）波形提供了优于常规脉冲有源声纳（PAS）波形的优势，也就是说，可以通过子脉冲处理对它们进行处理，以提供更高的目标更新率。在混响受限条件下的性能在浅水中尤为重要。本文比较了在沿海环境中同时发送的线性调频（LFM）PAS与等带宽LFM CAS波形同时处理的不同CAS亚脉冲持续时间下的信号混响比（SRR），回波电平和混响电平。来自海上试验的数据显示，就SRR而言，LFM PAS波形优于全频带LFM CAS波形3.0$ \ pm $2.1分贝。每减少一半子脉冲带宽和持续时间，CAS波形的SRR降低不到预期的3 dB。能量扩展损耗随带宽增加而增加，这是导致其与预期降级速率偏离的主要原因。通过接收机工作特性分析测得的全频带LFM CAS波形的检测性能近似等于LFM PAS波形的检测性能。