共查询到20条相似文献,搜索用时 78 毫秒
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针对舰船摇摆下,探雷声纳工作参数难以确定的特点,建立了舰船摇摆模型和探雷声纳多波束照射海底模型,定义了探雷声纳有效搜索面积,给出了舰船摇摆下探雷声纳工作参数的最优化设置建议,该方法简便有效,为探雷声纳的作战使用提供了依据。 相似文献
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针对水下声发射源较多,为能准确鉴别敌我声呐发射源问题.利用数字水印技术,结合分数阶傅里叶变换(FRFT)的良好时频特性,提出了基于分数阶傅里叶变换的声呐水印方法,通过在声呐信号的分数阶傅里叶变换域进行数字水印的嵌入,结合声呐信号在分数阶傅里叶变换的系数特性,选择合适的水印位置.利用嵌入前与嵌入后信号的特性自适应设定水印检测阈值,实现对声呐信号的鉴别.通过仿真分析验证了该方法的可行性,在仿真结果中示出该方法在保证具有较高的分辨力,以及较大的水印容量的同时,水印的鲁棒性较好,检测精度得到了进一步的提高. 相似文献
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水下声呐成像探测技术日益成为各国普遍重视的技术。声呐图像具有对比度低、成像质量差的特点,对声呐图像进行增强处理是进行声呐图像判读和提高视觉效果的基础之一。针对声呐图像增强算法研究较少等问题,提出了一种迭代阈值图像增强算法,并采用评价准则算法和频域响应法对常用的几种图像增强算法进行比较分析。结果表明,该方法具有算法简单、易于实现等特点,且增强效果可较好地满足视觉效果的需求。 相似文献
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Jenhwa Guo 《Journal of Marine Science and Technology》2008,13(2):147-153
This study presents a localization system using visual information for guidance and navigation of a biomimetic autonomous
underwater vehicle (BAUV). The BAUV tracks a mooring cable using two cameras and sonar. Sonar has good accuracy in detecting
longitudinal distances but is poor in detecting lateral distances. Since a stereo image has quantization errors, for the cameras,
measurement errors in lateral directions are less than those in the optic-axis direction. An extended Kalman filter was employed
to combine observational information derived from the cameras and sonar of the mooring cable position with the navigation
data of the BAUV. This work demonstrates, using water tank experiments, the effectiveness of the proposed tracking technique
in decreasing uncertainty in position estimations of the BAUV and mooring cable. 相似文献
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声呐系统测向精度指标是舰艇声呐系统的一个十分重要的战技指标.声呐系统作为舰艇作战系统的一个重要组成部分,它所提供测量数据精度的大小,直接关系到指控系统对鱼雷射击诸元的解算精度,从而影响鱼雷的射击效果.从理论上明确测向精度指标的描述问题,然后通过对声呐测向系统误差的校准,测向精度海上试验的航路约定的分析,研究并提出一种适应现代声呐高测向精度指标要求的测向精度真值解算方法,并对算法的误差进行详细分析. 相似文献
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根据相控阵多普勒声纳测试的需要,自主设计了基于PXI的相控声纳回波仿真模块设计,具有一路采集和四路回放,四路回波之间可以产生设定相对相移,同时,回放波形可以相对于采样波形有任意的频移、延时及衰减。该模块包括接口电路、DDS电路、存储电路、相移电路、A/D和D/A电路、衰减电路等,经试验验证,该模块具有通用性、高效性和易用性等特点,具有较高的实用价值。 相似文献
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This paper studies the algorithm of the adaptive grid and fuzzy interacting multiple model (AGFIMM) for maneuvering target tracking, while focusing on the problems of the fixed structure multiple model (FSMM) algorithm's cost-efficiency ratio being not high and the Markov transition probability of the interacting multiple model (IMM) algorithm being difficult to determine exactly. This algorithm realizes the adaptive model set by adaptive grid adjustment, and obtains each model matching degree in the model set by fuzzy logic inference. The simulation results show that the AGFIMM algorithm can effectively improve the accuracy and cost-efficiency ratio of the multiple model algorithm, and as a result is suitable for enineering apolications. 相似文献
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针对船舶动力定位状态估计时使用扩展卡尔曼滤波导致模型失配而产生滤波精度不高甚至滤波发散的问题,设计一种融合无迹卡尔曼滤波和粒子滤波的动力定位船舶状态估计算法.该算法以粒子滤波作为整体框架,运用无迹卡尔曼滤波对粒子状态的每次更新进行最优化估计,从而最优化了每个粒子的状态,再根据每个粒子的重要性分布,得出船舶复合运动中的低频状态.Matlab仿真结果表明,该方法能够从含有高频和噪声干扰的测量信息中估计出的船舶低频运动状态,相比于直接使用UKF,该方法的滤波精度更高,滤波性能也比较稳定. 相似文献
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SHEN Yan XIE Mei-ping 《船舶与海洋工程学报》2005,4(2):56-60
A DRNN (diagonal recurrent neural network) and its RPE (recurrent prediction error) learning algorithm are proposed in this paper . Using of the simple structure of DRNN can reduce the capacity of calculation. The principle of RPE learning algorithm is to adjust weights along the direction of Gauss-Newton. Meanwhile, it is unnecessary to calculate the second local derivative and the inverse matrixes, whose unbiasedness is proved. With application to the extremely short time prediction of large ship pitch, satisfactory results are obtained. Prediction effect of this algorithm is compared with that of auto-regression and periodical diagram method, and comparison results show that the proposed algorithm is feasible. 相似文献
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This paper studies the algorithm of the adaptive grid and fuzzy interacting multiple model(AGFIMM) for maneuvering target tracking, while focusing on the problems of the fixed structure multiple model(FSMM) algorithm's cost-efficiency ratio being not high and the Markov transition probability of the interacting multiple model(IMM) algorithm being difficult to determine exactly. This algorithm realizes the adaptive model set by adaptive grid adjustment, and obtains each model matching degree in the model set by fuzzy logic inference. The simulation results show that the AGFIMM algorithm can effectively improve the accuracy and cost-efficiency ratio of the multiple model algorithm, and as a result is suitable for engineering applications. 相似文献
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