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541.
542.
舰载直升机在护航编队中担负着很多重要的作战任务,由于索马里海域特殊的作战环境和海盗目标独特的特征,使得舰载直升机在中国海军护航编队遂行作战任务时对海盗目标的预警成为其重要任务之一。文章从护航编队舰载预警雷达对海盗目标预警探测的局限性和舰载直升机预警探测的优势出发,论证了舰载直升机对海盗目标预警探测的可行性、优点以及舰载直升机预警探测时应注意的事项,重点对舰载直升机探测海盗目标的应用方式进行了分析。 相似文献
543.
544.
国外光电无源干扰技术的发展 总被引:1,自引:0,他引:1
光电无源干扰技术在现代战争中发挥着越来越重要的作用。文章介绍了光电无源干扰技术的发展历程以及装备的研制、改进情况,指出了在现代战争中发展光电无源干扰技术的优势和重要性,重点探讨了几种光电无源干扰技术的性能及其特点,最后论述了光电无源干扰技术的发展动向与分析。 相似文献
545.
After an aerial object enters the water, physical changes to sounds in the water caused by the accompanying bubbles are quite complex. As a result, traditional signal analyzing methods cannot identify the real physical object. In view of this situation, a novel method for analyzing the sounds caused by an aerial object’s entry into water was proposed. This method analyzes the vibrational mode of the bubbles by using empitical mode decomposition. Experimental results showed that this method can efficiently remove noise and extract the broadband pulse signal and low-frequency fluctuating signal, producing an accurate resolution of entry time and frequency. This shows the improved performance of the proposed method. 相似文献
546.
基于相位差的方位估计(英文) 总被引:2,自引:0,他引:2
The phase difference method (PDM) is presented for the direction of arrival (DOA) estimation of the narrowband source. It
estimates the DOA by measuring the reciprocal of the phase range of the sensor output spectra at the interest frequency bin.
The peak width and variance of the PDM are presented. The PDM can distinguish closely spaced sources with different and unknown
center frequencies as long as they are separated with at least one frequency bin. The simulation results show that the PDM
has a better resolution than that of the conventional beamforming. 相似文献
547.
实际海浪环境大尺度模型试验遥控遥测系统(英文) 总被引:1,自引:0,他引:1
Physical testing of large-scale ship models at sea is a new experimental method. It is a cheap and reliable way to research
the environment adaptability of a ship in complex and extreme wave conditions. It is necessary to have a stable experimental
system for the test. Since the experimental area is large, a remote control system and a telemetry system are essential, and
were designed by the authors. An experiment was conducted on the Songhuajiang River to test the systems. The relationship
between the model’s speed and its electromotor’s revolutions was also measured during the model test. The results showed that
the two systems make it possible to carry out large-scale model tests at sea. 相似文献
548.
非结构化网格浸入边界法的流固耦合数值模拟(英文) 总被引:1,自引:0,他引:1
This paper presents an improved unstructured grid immersed boundary method. The advantages of both immersed boundary method
and body fitted grids which are generated by unstructured grid technology are used to enhance the computation efficiency of
fluid structure interaction in complex domain. The Navier-Stokes equation was discretized spacially with collocated finite
volume method and Euler implicit method in time domain. The rigid body motion was simulated by immersed boundary method in
which the fluid and rigid body interface interaction was dealt with VOS (volume of solid) method. A new VOS calculation method
based on graph was presented in which both immersed boundary points and cross points were collected in arbitrary order to
form a graph. The method is verified with flow past oscillating cylinder. 相似文献
549.
船舶远程识别与跟踪(LRIT)系统自建立并全功能运行以来,国际移动卫星组织(IMSO)作为LRIT协调人,制订了临时性的数据中心审核费计算公式,但在国际上一个广为接受的永久性计算公式仍未能确定。文中阐述了LRIT计算公式的最新制订进展,并对各种方案进行了分析,提出了下一步的工作建议。 相似文献
550.