基于参量阵的声呐发射机信号处理算法研究与实现

发布时间：2018-04-22 12:29

本文选题：参量阵 + 声呐　；参考：《电子科技大学》2016年硕士论文

【摘要】：声呐设备的用途十分广泛,其在军事和民事上的应用诱发了并大力推动了声呐技术的研究与发展。声呐技术的一个研究热点便是增加它的作用距离,但目前,各方面的原因都在一定程度上限制了其作用距离的增加。利用介质中的非线性作用,参量阵技术可以生成二次声波,这个声波的频率比较低,适合于远距离传播,该二次声波还具有很强的指向性。而且,由于原波的频率较高,所以发射阵的尺寸并不需要太大。参量阵的这些优点恰好可以应用在主动声呐之中,增大声呐的作用距离,并且其高指向性也能被很好地应用于声呐中,增加声呐的方位分辨力。本文研究声呐发射波形与参量阵调制技术的结合,分析DSB调制算法和SSB调制算法对CW信号和LFM信号的作用机制,利用Berktay远场解,分析CW信号和LFM信号在各个调制算法作用下所生成的二次声波的形式。通过对二次声波频域特性和时域特性的研究,得到几种可行的发射波形和参量阵调制技术的组合。结果表明,DSB法和全载波SSB法能很好地应用于参量阵声呐中,抑制载波SSB法不适用于参量阵声呐。全载波调制算法将产生频率为输入信号两倍的谐波,调制系数的降低有利于减少谐波失真,但同时也会降低有效信号的幅度。抑制载波DSB法产生二次声波的频率比较单一,其频率为输入信号的两倍,可以用做主动声呐的探测信号。通过对发射波束指向性控制的研究,提出了一种发射基阵阵列设计方法,设计了参量阵声呐的发射阵列,该平面阵采用5*15的矩形组阵形式,其水平方向上有5列,指向性开角为3.8度,垂直方向上有15行,指向性开角为13.1度。研究了参量阵声呐的相控偏转方法,利用时延波束合成技术,实现了本系统发射信号的相控发射。开发了一个基于FPGA的硬件处理平台,在该平台上完成了参量阵声呐的信号处理算法,包括:发射波形设计、调制算法、时延波束合成技术。在消声水池环境中,搭建了实验平台,通过对接收信号的波形和极大值方位的分析,验证了参量阵声呐的可行性,验证了本系统算法的正确性。
[Abstract]:Sonar equipment is widely used. Its application in military and civil affairs induces and promotes the research and development of sonar technology. One of the research hotspots of sonar technology is to increase its range of action, but at present, all kinds of reasons restrict the increase of its range to some extent. The parametric array technique can generate secondary sound wave by using nonlinear action in medium. The frequency of this sound wave is relatively low, which is suitable for long distance propagation, and it also has strong directivity. Moreover, due to the high frequency of the primary wave, the size of the emitter array does not need to be too large. These advantages of parametric array can be used in active sonar to increase the range of sonar, and its high directivity can also be applied to sonar to increase the azimuth resolution of sonar. In this paper, the combination of sonar emission waveform and parametric array modulation technology is studied. The mechanism of DSB modulation algorithm and SSB modulation algorithm on CW signal and LFM signal is analyzed, and the far field solution of Berktay is used. The form of quadratic acoustic wave generated by CW signal and LFM signal under the action of each modulation algorithm is analyzed. Based on the study of frequency domain and time domain characteristics of quadratic acoustic wave, several feasible waveforms and parametric array modulation techniques are obtained. The results show that the DSB method and the full carrier SSB method can be applied to parametric sonar very well, but the suppression carrier SSB method is not suitable for parametric sonar. The full-carrier modulation algorithm will produce harmonics twice the frequency of the input signal. The decrease of modulation coefficient will help to reduce the harmonic distortion, but also reduce the amplitude of the effective signal. The frequency of secondary acoustic wave produced by suppressing carrier DSB method is single, and its frequency is twice that of input signal, so it can be used as the detection signal of active sonar. Based on the research of beam directivity control, a design method of emission matrix array is proposed, and the emission array of parametric sonar is designed. The planar array is a rectangular array with 5 columns in horizontal direction. The directivity angle is 3.8 degrees, the vertical direction is 15 rows, and the directivity angle is 13.1 degrees. The phase-controlled deflection method of parametric sonar is studied. The phased emission of the system is realized by using the time-delay beam synthesis technique. A hardware processing platform based on FPGA is developed, on which the signal processing algorithm of parametric sonar is completed, including: waveform design, modulation algorithm and time-delay beam synthesis technology. The experimental platform is built in the environment of the silencing tank. The feasibility of the parametric sonar is verified by analyzing the waveform and maximum azimuth of the received signal, and the correctness of the system algorithm is verified.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN830

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