火箭发射的次声信号分析*

在距离发射点20km和230km的两个阵列上，记录了我国一次火箭发射产生的次声波。从信号中识别出点火与声爆事件，观察到火箭在飞行中产生持续的次声波，以及声爆前后明显能量特征上的变化，观测到完整的火箭发射和飞行过程中系列次声波。为了验证采集信号中包含声爆事件，使用Fisher检测估计方位角和视速度，计算结果与火箭飞行轨迹一致，并且声爆信号的预计到达时间和估计方位与实际的时间和方位角相符合。结合火箭速度变化的特征，给出了声爆前低频能量较弱现象的解释和火箭超声速后次声能量特征的变化，揭示了火箭产生次声波的机理，为火箭发射等目标的监测提供有益的借鉴和参考。

Analysis of the infrasound signals from rocket launch

The infrasound generated by a domestic rocket launch was recorded at two receiving arrays 20km and 230km apart respectively. Ignition and sonic boom events are identified from the signal. The continuous infrasound generated by rocket in flight and the obvious energy characteristics changes before and after the acoustic explosion are observed. A complete series of infrasound waves during rocket launching and flight are observed. In order to verify that the observed signals contain sonic boom, Fisher detection is used to estimate the azimuth and apparent velocity. The results are in good agreement with the trajectory of the rocket. The estimated time and azimuth of the sonic boom signals match those observed. Combining the characteristics of rocket velocity changes, the explanation of the low-frequency energy weak phenomenon before sonic boom and the change of infrasound energy characteristics after rocket supersonic speed are given. The mechanism of infrasound generation by rocket is revealed, which provides useful reference for the monitoring of rockets and other targets.