【作者】 徐祥；

【导师】 方世良； 田华玲；

【作者基本信息】 东南大学 ， 电子与通信工程， 2016， 硕士

【摘要】 ADCP(Acoustic Doppler Current Profilers,声学多普勒流速剖面仪)是二十世纪八十年代初发展起来的一种测流设备,主要用来测量大范围海流的速度,在河流测量中有着极为广泛的应用。系统基本原理是利用多普勒效应,得到与发射信号对应的水流回波并对回波信号进行分层、计算,得到剖面流速信息。本文在对ADCP技术的基本理论和Matlab建模进行研究后,提出了环境适应思想并将其运用到ADCP系统当中。同时针对测量中出现的测速模糊和层间干扰这两个测量时不可避免的问题提出改进方案,完成了系统软件平台的搭建和水上实验分析,论文具体内容如下：1.简述ADCP测流的基本原理。对多普勒效应、不同换能器的阵列形式、水流分层概念、底跟踪测量方法进行简要介绍,论证了回波信号与空间分层的对应关系,从盲区和旁瓣干扰两个角度探讨了ADCP测流的局限性。2.对基于复自相关理论的频率估计方法在ADCP测流中的可行性进行了验证；分析了不同测流方式的性能,包括窄带非相干测流、窄带相干测流和宽带测流,得出宽带测量通过编码改善了信号相关性,增大了时间带宽积,是对窄带非相干和窄带相关两种测流方式的优点结合的结论；通过改变发射信号参数,验证发射信号形式对测流性能的影响。3.针对ADCP测量中出现的测速模糊和层间干扰这两个问题,提出一种基于脉冲延时变化的解模糊算法,同时针对解模糊范围、解模糊准确性和具体实现这三者之间的矛盾,通过组合判定对原有算法进行改进。对于测量时的层间干扰问题,提出使用滑动平均算法抑制层间干扰,通过精细化分层增加滑动平均算法的样本点,进一步抑制了层间干扰。通过Matlab验证了以上两种算法的可行性。4.完成了基于CCS的OMAPL138处理器的软件开发,在软件中实现上述两种算法。系统中加强了开发板与各模块之间的通信,信号和算法参数均可以根据环境的不同实时改变,为环境适应思想提供了软件支持。同时进行了场外水上实验,分析实验结果验证了算法的可行性。更多还原

【Abstract】 Acoustic Doppler Current Profilers is a kind of the current measurement equipment which was developed in the early 1980s.It is mainly used to measure the speed of a wide range of ocean current, and has been widely used in the river measurement. Based on the Doppler effect, the system receives the doppler frequency of the echo corresponding to the emission signal, layers and calculates the echo signal to gain the profile velocity information. Based on the basic theory of ADCP technique and the numerical modeling, the thesis proposes the idea of the adaptive environment and applies it to the ADCP system, improves the scheme to solve the measuring speed fuzzy and the interlayer interference, which are inevitable in measurement procedure, and finally completes the construction of the system platform and the water experimental analysis. The main works of this thesis are as follows:1. The basic principle of ADCP current measurement is described firstly. The thesis introduces the doppler effect, the different transducer array and the method of measurement at the bottom, demonstrates the relationship of the echo signal and spatial layer, and then discusses the limitation of ADCP current measurement from two aspects:the blind area and the sidelobe disturbance.2. The feasibility of the frequency estimation method is verified based on the theory of the complex autocorrelation in the ADCP current measurement; the performance of different measurement methods are analyzed, including the narrowband incoherent measurement, narrowband coherent measurement and broadband measurement, and it is concluded that the broadband measurement improves the signal correlation and increases the time bandwidth product through coding, because of the combination of the advantages of the narrowband incoherent measurement and the narrowband coherent measurement; the effect of transmitting form is verified through the performance of the speed measurement with changing the parameters of the transmitting signal.3. A kind of ambiguity resolution algorithm is proposed based on the pulse delay variation, to resolve the problems of the measuring speed fuzzy and the interlayer interference. At the same time, the thesis improves the original algorithm by combining determination, which resolves the contradiction of the ambiguity resolution scope, the ambiguity resolution accuracy and the implementation. On the other hand, the thesis uses the moving average algorithm to restrain the interlayer interference in order to resolve the problem of the interlayer interference during the measurement, and further restrains the interlayer interference by increasing the sample points. The feasibility of the above two algorithms are verifiesd by numerical simulations.4. The ADCP system is developed based on the CCS and OMAPL138 processor. The thesis describes the modules of the algorithm, and strengthens the communication between the development board and the various modules. The signal and algorithm parameters can be changed depending on the environment in real time, and the software support is provided for the environmental adaptation. Finally, the outdoor water experiment is carried out, where the experiment result is analyzed and the feasibility of the algorithms above is verified.更多还原