Resolving Velocity Ambiguity in Multifrequency, Pulse-to-Pulse Coherent Doppler Sonar
Resolving Velocity Ambiguity in Multifrequency, Pulse-to-Pulse Coherent Doppler Sonar
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DOI：
10.1109/joe.2010.2066710
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发表时间：
2010-10
影响因子：
4.1
通讯作者：
L. Zedel;A. Hay
中科院分区：
文献类型：
--
作者：
L. Zedel;A. Hay
相干多普勒声纳允许无创速度测量，适用于实验室和现场应用。该方法在光学技术因功率要求或更重要的水浊度而不适用的环境中特别有吸引力。值得注意的是，该技术已成功应用于海洋和河流边界层研究。然而，距离和速度模糊性的出现限制了该技术的更广泛应用。本文介绍了一种通过宽带发射脉冲同时采集两个（或更多）频率的声学反向散射来克服速度模糊的方法。不同的频率具有不同的速度模糊度，从而可以消除速度测量的歧义。该方法在概念上类似于使用多个传输脉冲速率，但具有可以同时采集数据的优点，因此不会损失数据速率。此外，系统几何形状通常限制允许的脉冲重复率，使得使用频率的消歧更加灵活且更普遍适用。理论上，双频系统的有效模糊度速度可以任意扩展，但实际系统中的相位噪声将该方法限制在模糊度速度大约增加五倍。
Coherent Doppler sonar allows noninvasive velocity measurements and is suitable for both laboratory and field applications. The approach is particularly attractive in those environments where optical techniques are not suitable either because of power requirements or more critically, water turbidity. Notably, the technique has been employed successfully in oceanic and river boundary layer studies. However, the occurrence of range and velocity ambiguities limit the more general application of the technique. This paper introduces a method to overcome speed ambiguities by acquiring acoustic backscatter at two (or more) frequencies simultaneously with a broadband transmit pulse. The different frequencies have distinct velocity ambiguities allowing disambiguation of the velocity measurements. The approach is conceptually similar to the use of multiple transmit pulse rates but has the advantage that the data can be acquired simultaneously and so there is no loss in data rate. In addition, system geometry often restricts the allowed pulse repetition rate so that disambiguation using frequency is more flexible and more generally applicable. Theoretically, the effective ambiguity velocity of a dual-frequency system can be extended arbitrarily but phase noise in a practical system restricts the method to about a fivefold increase in ambiguity velocity.