基于互相关函数法的海水声速测量方法研究

Study on measurement method of seawater sound speed based on crosscorrelation function

精准的海水声速测量具有重要意义,高精度的时差估计是使用时差法进行声速测量的关键.针对时差测量精度不高而导致海水声速测量准确性低的问题,本文采用互相关函数法进行时差估计,并利用插值技术提高时差估计精度.该方法利用发射超声波信号与接收超声波信号之间相关性强,超声信号与随机噪声相关性弱的特点,将发射信号和接收信号滤波、去噪后,作互相关处理,计算延时.通过实验可以证明,此方法可提高时差估计精度,进一步可提高时差法测量海水声速的准确性.

High-precision measurement of seawater sound speed has a great significance, and the key to water sound velocity measurement problem is the time delay estimation. During the seawater sound speed measurement by using difference method, to resolve the problem that the measurement accuracy of seawater sound speed is tow caused by ~he time difference measurement accuracy is not high, cross-correlation function method was used to measure the speed of sound in seawater, and using interpolation technique to improve the precision of time delay estimation. The method utilizes the characteristics that the transmitting signals ultrasonic and the receiving uhrasonic signals have a strong correlation and the weak correlation with random noise, which makes the transmit signals and receive signals for cross-correlation process and filters out noise and other interfering signals. The experimental results show that this method can improve the accuracy of measurement of the difference of the speed of sound seawater.