共查询到16条相似文献,搜索用时 143 毫秒
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研究了双线阵在两种阵形畸变(轴向滑移和航向偏差)条件下的左右舷分辨性能,根据双线阵指向性函数的背瓣特性分析了阵形畸变对左右舷分辨性能的影响。理论分析表明,在无阵形畸变的理想阵形情况下,窄带信号的左右舷分辨能力取决于阵间距和信噪比,而对宽带信号,左右舷分辨能力不仅与阵间距和信噪比有关,而且还与接收信号的功率谱密度、处理频段有关。在阵形发生轴向滑移和航向不一致的情况下,在正横方向附近,左右舷分辨性能主要受双线阵的航向差影响,偏离正横方向,较大的轴向滑移会导致左右舷误判。 相似文献
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基于二元假设检验理论,研究了双线列阵对目标方位左右舷分辨的正确和错误概率。根据阵列接收窄带信号的概率密度函数,定义了左右舷判决统计量,当信号快拍数足够大时,左右舷判决统计量接近正态分布,从而可得到窄带信号的左右舷分辨概率。利用子带信号左右舷分辨概率的频率加权或波束加权,得到频率或波束加权的宽带信号左右舷分辨概率。理论和数值分析表明,窄带信号的左右舷分辨概率取决于双阵间距,而宽带信号的左右舷分辨概率对阵间距的宽容性较大。 相似文献
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双线列阵左右舷目标分辨性能的初步分析 总被引:16,自引:7,他引:9
以单水听器阵列构成的单线阵声呐无法区分目标来自左舷或右舷。多线阵为解决左右舷目标的模糊问题提供了一种途径,本文讨论双线列阵左右舷目标分辨的性能,提出把波束指向方向的响应对对称方向的响应的抑制比作为评估左右舷分辨能力的一个参数,并对抑制比的性能作了初步分析,给出了理论表达及实际计算结果。理论分析结果对实际双线列阵设计中的参数选择具有重要意义。 相似文献
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References: 《声学学报:英文版》2008,27(1):23-33
The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results. 相似文献
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References: 《声学学报:英文版》2007,26(4):337-344
A passive synthetic aperture based on phase correction algorithm for solving the port-starboard discrimination problem in the non-aligned towed twin-line array sonar,is de- scribed.This method creates a virtual array through applying the estimated phase correction into one array of twin-line arrays.Because the synthetic virtual array is aligned with the other array in twin-line arrays,the right port-starboard discriminated results can be obtained by array processing based on the new synthetic twin-line array.The effect of proposed method has been shown by simulated and sea-trials results in towed twin-line array sonar.With low extra computational loads,the proposed method is easy to apply to the practice. 相似文献
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矢量水听器线阵和弧线阵抗左右舷模糊性能分析 总被引:1,自引:0,他引:1
针对线阵声纳左右舷模糊问题,建立了基于矢量水听器直线阵 和 两种信息处理模式以及标量水听器弧线阵不同布阵方式的抗左右舷模糊性能数学模型,分析了不同布阵方式以及不同信息处理模式的抗左右舷模糊性能,并进行了仿真计算。分析和仿真结果表明,矢量水听器直线阵和标量水听器弧线阵在分辨左右舷性能和观察范围上各有优势。矢量水听器直线阵虽然可分辨左右舷且在作用距离上具有优势,但由于在一定扇面内分辨左右舷是依靠声纳方位历程图的明暗差异,在多目标情况下易造成声纳观察上的干扰;具有一定弧心角的标量水听器弧线阵,可以在更宽的扇面内具有抗左右舷模糊能力,但其以减小观察范围作为代价。 相似文献
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针对单线阵左右舷模糊问题,提出了结合盲源分离的非直单线阵多目标左右舷分辨算法。该算法首先通过离散傅里叶变换将阵列接收信号离散化为若干个窄带频谱分量,之后对每个频点的窄带数据讲行盲源分离,得到每个频点上各个来波信号的导向向量;然后通过常规波束形成对各个导向向量进行方位谱估计,并根据左右舷抑制比进行单目标左右舷分辨,确定各个频点上的来波方向;最后对所有频点上的来波方向进行聚类,得到各个真实目标的方位,从而实现多目标左右舷分辨。仿真实验中,相比常规波束形成方法(CBF)和最小方差无畸变响应算法(MVDR),该算法更准确地估计出了目标数目,且保持了较快的计算速度;海试数据处理中,该算法排除了目标镜像的干扰,准确估计出了船只目标的轨迹。仿真及海试数据处理均表明,该算法可以分辨真实目标与目标镜像,具有比CBF和MVDR算法更好的左右舷分辨能力。 相似文献
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The energy ratio of broadband signal is utilized for port/starboard discrimination in towed line array with hydrophone triplets in tradition.It works well in most conditions except for two cases:One is low signal to noise ratio(SNR),and the other is that there is a stronger interference lied on the other side of the line array with approximate bearing angles. A method called line-spectrum character extracting is proposed to discriminate port/starboard for these two cases in this paper,and the SNR needed for port/starboard discrimination is reduced significantly.Simulation and the sea-trial data are analyzed to show that the method is stable and valid,and is expected to be applied in real towed line array sonar.A line-spectrum enhancing technology with lower calculation complexity and stable validity is proposed to ensure the application of this method in lower SNR condition. 相似文献
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The design of aperture weightings in ultrasound arrays is a multi-objective optimization problem, involving parameters such as delays, aperture size, focal depth, operating frequency and beam properties. Besides, apodization causes the SNR in array output to be decreased. We introduce an analytic expression of the lateral point spread function and a model for SNR as nonlinear functions of weights, based on which, a new aperture design method is established, resulting in an optimal set of weights. These weights provide a point spread function having the predetermined peak sidelobe level, while the SNR in array output is optimized. Optimization results from a linear array with M=128 elements equally spaced at one wavelength, center frequency f0=3.5 MHz and 50% relative bandwidth, have shown that decreasing the peak sidelobe level, decreases the SNR. Therefore, an array designer can select a proper set of weights according to its application, using a SNR curve versus to the peak sidelobe level. In addition, the method can maintain the same beam properties over a long range with low variations in the SNR. Simulation results have shown only 1 dB variations in the SNR for depths from 20 mm to 120 mm, which is a longer range and better SNR performance than the conventional methods. 相似文献