如何提高水下测距精度是水声测距的要点和难点。本文采用线性调频信号（LFM）为发射信号，使用分数阶傅里叶变换（FrFt）处理提高距离分辨率，在已测海底深度的前提下，利用界面反射信号与直达信号的声程差对非同步条件下测量水下声源的精确距离的影响因素进行研究，并通过海上实验验证得到使用LFM信号利用分数阶傅立叶变换可有效提高测距精度，在已知海深的前提下可精确测量非同步发射源位置，测量精度与已知海深精度和发射信号时间带宽积有关。
Improving ranging accuracy in the water is very important and difficult. This article chooses the pulse with linear frequency-modulation (LFM) for transmit signal. For improved ranging accuracy, using fractional Fourier transform (FrFt) analyzed signals. When the bed deep was knew, using distance differences of interface echo and direct sound, research on influence factor of non-synchronization measuring distance exactly of source in the water. The experimentation was performed, and results are as follows:When LFM was used and using FrFt analysis, to compare with tradition method ranging accuracy was improved. The ranging accuracy depend on the bed deep and bandwidth of signal.
2019,41(3): 131-136 收稿日期：2017-11-28
DOI：10.3404/j.issn.1672-7649.2019.03.026
分类号：U666.7
作者简介：曹清刚(1982-),男,工程师,研究方向为水声工程及信号处理
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