噪声修正的混响反演海底反射系数幅值参数
Inversion for amplitude parameter of bottom reflection coefficient by using reverberation with noise correction
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摘要: 利用一种噪声修正方法解决低混噪比条件下混响数据反演海底反射系数幅值参数偏差的问题。将全波动混响理论中的混响非相干平均强度,叠加海洋环境噪声平均强度,获得包含噪声的混响平均强度理论,分析背景噪声平均强度对反演海底反射系数幅值参数的影响。数值仿真表明,背景噪声平均强度的叠加使得混响平均强度衰减趋势减缓,导致海底反射系数幅值参数反演结果偏小,混响噪声比越低,影响越明显。提出一种噪声平均强度相减的修正方法,对混响噪声比为0,6 dB的混响平均强度数据进行修正,利用修正后的混响数据反演得到偏差较小的海底反射系数幅值参数。对比浅海混响实验数据衰减至不同混噪比时反演所得海底反射系数幅值参数,以及经噪声修正后的反演结果,验证了本文提出方法的可行性。Abstract: Low reverberation-noise ratio makes it difficult to inverse reliable amplitude parameter of bottom reflection coefficient from reverberation data.In order to reduce the error of the inversion result,a method of noise correction is proposed.The average intensity of reverberation containing that of noise is obtained by overlaying the average intensity of marine environmental noise with the incoherent average intensity of reverberation based on the full-wave reverberation model.The effect of the average intensity of noise on the inversion results of amplitude parameter of bottom reflection coefficient is analysed.The simulation results indicate that the superposition with energy of ambient noise can slow down the trend of reverberation average intensity.As a result,smaller amplitude of bottom reflection coefficient will be gotten.And the effect is more obvious with reverberation-noise ratio decreasing.The accurate amplitude parameter of bottom reflection coefficient is supposed to be obtained from data of reverberation average intensity decaying to 0,6 dB of reverberation-noise ratio by subtracting the average intensity of noise.The experimental data analyse inversion results from data decaying to different reverberation-noise ratio before and after noise correction.The numerical results verify that the noise correction can increase the data utilization on the premise of decreasing the derivation of inversions results from real value effectively.