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661.
防空导弹武器兵力分配优化模型 总被引:2,自引:0,他引:2
高尚 《南京航空航天大学学报》2000,32(3)
兵力优化分配是防空作战部署中的重要问题。文中利用排队论、对策论理论和方法 ,研究了防空导弹兵力分配问题 ,建立了防空导弹兵力分配优化模型及其解法。给出了一个实例 ,并用线性规划方法得到了最优混合策略。最后讨论了实战中的情况与基本假设不符合时的解决方法。对于多通道的导弹武器部署问题可用类似的方法处理 ,此方法为防空导弹部署优化提供了一个基本思路。 相似文献
662.
SIMOTION在数字化对接系统中的多轴同步控制应用 总被引:1,自引:0,他引:1
针对数字化对接系统,基于运动控制系统SIMOTION提出了虚拟轴的方法,实现多轴同步控制,开发了SIMOTION控制接口软件,实现数据和指令的可靠传输。数字化对接系统中的试验结果验证了多轴同步控制方法的有效性。 相似文献
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Aeroelastic analysis of a shipboard helicopter rotor with ship motions during engagement and disengagement operations 总被引:2,自引:0,他引:2
An aeroelastic simulation of a shipboard helicopter rotor with ship motions during engagement and disengagement operations is investigated to explore the coupled dynamic behavior between the rotor and the ship. A finite element analysis based on a moderate deflection beam model is employed to capture the flap, lag and torsion deflections of the rotor blade. The ship is treated as a six-degree-of-freedom rigid body. By using the Hamilton?s principle, system equations of motion are derived based on the generalized force formulation. The responses agree well with the test data of the rotor blade droop stop impact and the transient aeroelastic response of the shipboard teetering model rotor. Parametric investigations illustrate that the ship pitch motion has significant influence on the maximum negative displacement of the blade tip. Additional over 25% increase of the tip deflection can be introduced by the ship pitch motion. The aerodynamic and inertial couplings between the ship motion and the rotor have significantly nonlinear influence on the transient aeroelastic response. Both terms should be taken into account in the coupled helicopter–ship dynamics model. 相似文献
666.
阐述外层空间活动具有现实和潜在的安全问题,指出国际法中的外层空间法存在的不足和漏洞,阐明应借鉴发达国家的做法,通过国内立法来维护我国外层空间活动安全的必要性和可行性,并对如何立法提出初步设想。 相似文献
667.
Youtao Gao Zhicheng You Jingyu Liu Bo Xu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(6):1733-1742
The right ascension of the ascending node is unobservable if only the inter-satellite ranging is used for autonomous orbit determination (AOD) of an Earth navigation constellation. However, if an Earth-Moon libration point satellite is added to the Earth navigation constellation to construct an extended navigation constellation, all the orbital elements can be determined with only the inter-satellite ranging. Furthermore, the extended navigation constellation can provide navigation information for interplanetary probes. For such an extended navigation constellation, orbital control needs to be considered due to the instability of the libration-point satellite orbit. This study concerns the influence of satellite orbital maneuver on the AOD of the extended navigation constellation. An AOD method under orbital maneuver is proposed. A low thrust controller is designed to achieve libration point satellite autonomous orbit maintenance by using AOD results. A navigation constellation consisting of three GPS satellites and one libration point satellite are designed for simulation. The simulation results show that libration point satellites can achieve autonomous navigation and autonomous orbit maintenance by only using inter-satellite ranging information. The rotation drift error of the Earth navigation constellation is also suppressed. 相似文献
669.
Zheng Li Peng Chen Naiquan Zheng Hang Liu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(4):1317-1332
In recent years, with the continuous development of Global Navigation Satellite System (GNSS), it has been applied not only to navigation and positioning, but also to Earth surface environment monitoring. At present, when performing GNSS-IR (GNSS Interferometric Reflectometry) snow depth inversion, Lomb-Scargle Periodogram (LSP) spectrum analysis is mainly used to calculate the vertical height from the antenna phase center to the reflection surface. However, it has the problem of low identification of power spectrum analysis, which may lead to frequency leakage. Therefore, Fast Fourier Transform (FFT) spectrum analysis and Nonlinear Least Square Fitting (NLSF) are introduced to calculate the vertical height in this paper. The GNSS-IR snow depth inversion experiment is carried out by using the observation data of P351 station in PBO (Plate Boundary Observatory) network of the United States from 2013 to 2016. Three algorithms are used to invert the snow depth and compared with the actual snow depth provided by the station 490 in the SNOTEL network. The observations data of L1 and L2 bands are respectively used to find the optimal combination between different algorithms further to improve the accuracy of GNSS-IR snow depth inversion. For L1 band, different snow depths correspond to different optimal algorithms. When the snow depth is less than 0.8 m, the inversion accuracy of NLSF algorithm is the highest. When the snow depth is greater than 0.8 m, the inversion accuracy of FFT algorithm is higher. Therefore, according to the different snow depth, a combined algorithm of NLSF + FFT is proposed for GNSS-IR snow depth inversion. Compared with the traditional LSP algorithm, the inversion accuracy of the combined algorithm is improved by 10%. For L2 band data, the results show that the accuracy of snow depth inversion of various algorithms do not change with the variations of snow depth. Among the three single algorithms, the inversion accuracy of FFT algorithm is better than that of LSP and NLSF algorithms. 相似文献