宽带声学多普勒流速剖面仪回波信号模型分析

The model analysis of volume reverberation for broadband Acoustic Doppler Current Profile

宽带声学多普勒流速剖面仪(Broadband Acoustic Doppler Current Profile,BBADCP)通过接收海洋体积混响信号进行频偏估计,体积散射模型的准确性决定了理论仿真的正确性。针对BBADCP的信号模型特点,建立了散射体单元散射叠加效应的海洋体积回波时空特性及散射模型,推导了叠加噪声后散射回波的具体表达式。通过散射回波的离散化,把各参数(幅度、频率、调制)分离开来,单独考虑各参数对测速精度的影响。利用复协方差算法对水流流速进行估计,分析了信噪比、水流流速、紊流效应等因素对BBADCP流速估计的影响,验证了体积散射模型的正确性。

By receiving ocean volume reverberation, the broadband Acoustic Doppler Current Profile estimates the Doppler shift of ocean current. The correctness of volume reverberation model decides the correctness of theoretical simulation. From the signal model of BBADCP and the superposition effect of reverberation cell, the spatio-temporal characteristics of ocean volume reverberation and the model of volume reverberation are created, and the formula of reverberation signal, added with noise, is deduced. According to the dispersion of volume reverberation, the parameters split from each other, and the effects of amplitude, frequency and modulation on speed estimation are severally consi- dered. Also the effects of SNR, current velocity, and turbulence on BBADCP are analyzed. The results validate that the volume reverberation model is correct.