基于超声相控技术的船舶吃水测量方法

Measurement method of ship draft based on ultrasonic phase control technology

为了解决内河船舶因超吃水引起的通航阻塞以及船舶安全问题,提出一种基于超声相控技术的船舶吃水测量方法。以超声相控技术为理论基础,通过控制一维线型超声相控阵列换能器发射聚焦声波,实现对目标船舶的相控扫描,获取各扫描点的回波信号;利用匹配滤波算法对回波信号进行滤波,改善信噪比;利用阈值法提取回波信号的时延;利用渡越时间法,计算出扫描点到各发射振元中心的距离,利用双曲交汇法计算出扫描点的空间坐标;分析回波信号幅值和扫描点位置坐标即可得到船舶吃水深度。为验证方法的可靠性,搭建了小比尺船模吃水测量实验系统,分析了110~140 mm不同吃水深度下的实验结果,计算了实际吃水与测量吃水间的相对误差。实验结果表明,使用匹配滤波法处理后的回波信号信噪比从15.26 dB提高至36.39 dB,实验时,最大相对误差出现在船舶实际吃水130 mm时,绝对误差为2.3 mm,相对误差为1.7%。

In order to solve the navigation jam and ship safety problems caused by excessive draft of inland ships,a ship draft measurement method based on ultrasonic phase control technology is proposed.In this method,an onedimensional linear ultrasonic phased array transducer emits the focused sound wave to perform phase control scan for the target ship to obtain the echo signal from each scanning point;then the matched filtering algorithm is used to improve the signal to noise ratio of echo signal,and the time delay of echo signal is extracted by threshold method;finally,the transit time method is used to calculate the arrival time of scanning point.The space coordinates of scanning points are calculated by hyperbolic intersection method,and the ship draft can be obtained by analyzing the amplitudes of echo signals and the position coordinates of scanning points.An experimental system for measuring the draft of small scale ship model is built to verify the effectiveness of the method.The experimental results of different drafts of 110~140 mm are analyzed,and the relative error between the actual draft and the measured draft is calculated.It is shown that the signal to noise ratio of the echo signal processed by the matched filtering method increases from 15.26 to 36.39 dB.The maximum relative error of the experiment occurs when the actual draft of the ship is 130 mm,the absolute error is 2.3 mm,and the relative error is 1.7%.