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水中目标强度的一致性时域有限差分计算
Uniform finite-difference time-domain method for underwater target strength estimation
【摘要】 本文应用一致性时域有限差分法(FDTD)和近场 远场变换计算散射声目标的反射声压强度,找出反射声压级与目标声中心到换能器间距离的关系。数值计算中考虑了自由场和有海面及海面波浪影响时的不同情况。根据声源和目标的几何特征对入射波和散射波分别作了球面和柱面扩散修正,并将计算结果与水池实验结果进行了比较。本文的讨论可对水下目标强度测量方法提供参考。
【Abstract】 Using the finite difference time-domain (FDTD) method and near field to far field transformation, pressure of the reflected sound from the scattering target is calculated. The aim is to find the relationship between the reflected sound pressure and the distance from the transducers to the target. In the calculation, both free field and surface bounded field with surface waves are considered. Spherical and cylindrical corrections are made based on the geometry of the source and the target. The calculated results are compared with the measured data. The method described may provide a means to aid the target strength measurement.
【Key words】 FDTD； target strength； scatteringA method for improving the performance of ALE using two coherent accumulators$$$$ WANG Yan, MA Zhang yong,HUANG Jian ren (Department of Radio Engineering,Southeast University,Nanjing 210018,China)Abstract:Underwater acoustic channels are usually time varying with strong noise, in which various signals with narrow bandwidth are superimposed. Using conventional filters or adaptive spectral line enhancers to detect CW signals is not ideal in these channels. In this paper, a method based on ALE using two coherent accumulators is introduced, which attempts to adjust the IIR filter to treat CW signals. Its performance in low SNR channels is satisfactory. In addition, implementation of the technique is simple. Computer simulation results are also presented. Key words: adaptive spectral line enhancer； coherent accumulate； noise suppression；
- 【文献出处】 声学技术 ,Technical Acoustics , 编辑部邮箱 ,2003年01期
- 【分类号】O427.2
- 【被引频次】1
- 【下载频次】157