一种水声声速的时频测量综合算法研究

Research on a Time-frequency Measurement Algorithm for Underwater Acoustic Velocity

针对飞行时间测量法中信号起振点难以检测而导致的测量误差问题,提出了一种基于时频的综合测量算法,以获得高精度超声波声速。首先运用信号时域互相关法,测量声波飞行的整周期时间;再利用信号频域信息中相位差,获得超声传播群延时信息;最终通过时域与频域综合信息获得高精度的飞行时间测量,从而提高声速的测量精度。声速测量平台采用“FPGA+微处理器”架构,对提出的方法进行验证,实测数据结果表明该声速时频测量算法有效,并具有较好的实用价值。

It s difficult to detect the starting point of signal during measuring time-of-flight of sound propagation,caused by which measurement error should be eliminate.A comprehensive measurement algorithm based on time-frequency analysis is proposed to obtain high-precision ultrasonic velocity.Firstly,cross-correlation method within time domain is used to measure the whole cycle time of sound wave traveled;then,phase difference in the signal frequency domain is used to obtain the ultrasonic propagation group delay information;finally,the high-precision time-of-flight measurement is obtained by combining time and frequency domain information,so as to improve the measurement accuracy of sound velocity.By building the sound velocity measurement platform employed“FPGA+microprocessor”architecture,results show that the algorithm is effective and instructive to practice.