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Zhao N.,Nanjing University of Science and Technology | Yu Y.-G.,Nanjing University of Science and Technology | Lu X.,Nanjing University of Science and Technology | Li S.-D.,Xichang Satellite Launch Center
Dandao Xuebao/Journal of Ballistics | Year: 2013

The circumferential distribution characteristics of the spray field of the impinging jet in the atmosphere were studied by using phase-Doppler particle dynamic analyzer(PDA). The results indicate that, under the injection pressure of 0.8-1.8 MPa, the uniformity at circumferential distribution of the droplet spray parameters(D32, vz and vr) improves with the increase of the axial distance, while it gets worse at the position further away from the nozzle under the injection pressure of 2.2-2.6 MPa. The distribution uniformity of the spray parameters along the axial and radial direction was quantified by the radial nonuniformity index(RNI)theory, and the results agree with the test ones. It proves that the RNI theory is a useful method to represent the nonuniformity of spray field. Source

Guo Z.,Xichang Satellite Launch Center | Li Q.,Beijing Institute of Technology
Proceedings of the International Astronautical Congress, IAC | Year: 2013

This paper focuses on system level EMC database modeling of spacecraft. Since there are many electromagnetic interference sources for the sensitive electron devices on the spacecraft, kinds of different EMI sources will be discussed at the beginning. The EMI radiated sources such as strong electromagnetic pulse, various payloads radiated emissions and high-power AC/DC conducted emissions etc will be analyzed in details. After that, as for sensitive devices easily to be interfered by others types of EMI sources, the EMI estimation formulae will be deduced. Following that, according to deduced EMI estimation formula, the EMI prediction models for sensitive devices will be given out. Because of several of sensitive devices on the spacecraft, different database estimation model should be made according to the allowed EMI safeguard levels. Based on which has been discussed spacecraft database of EMC, the subsystem (equipment) level devices EMC prediction can be simulation under this model. This design methodology can be used in spaceflight project of the various payloads to ensure compliance with the stringent EMI requirements.Copyright ©2013 by the International Astronautical Federation. Source

Liang S.,Anhui University of Science and Technology | Peng C.,North China Institute of Science and Technology | Liao Z.,Xichang Satellite Launch Center | Wang Y.,Anhui University of Science and Technology
International Journal of Control, Automation and Systems | Year: 2015

A class of uncertain fractional order systems is concerned where intervals of system matrices parameters are affected by the fractional order. Moreover, the order is also uncertain and belongs to an interval containing the integer one. This kind of system models are reasonable results of fractional order system identifications. In this note, we derive the robust stability analysis and synthesis of such uncertain fractional order systems. Two numerical examples are presented to illustrate the effectiveness and potential of the developed theoretical results. © 2015, Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg. Source

Han Y.,National University of Defense Technology | Zheng Z.,National University of Defense Technology | Chong Y.,Xichang Satellite Launch Center
2015 IEEE International Conference on Information and Automation, ICIA 2015 - In conjunction with 2015 IEEE International Conference on Automation and Logistics | Year: 2015

Integrated guidance and control laws have the potential to improve the overall performance of missile systems by taking advantage of the synergism existing between the subsystems. This paper examines the proposed integrated guidance and control by using θ - D suboptimal method to the engagement of ground-fixed target. First, the basic longitudinal mathematical integrated guidance and control model is established. next, a new suboptimal control method, called θ - D, is employed to obtain an approximate closed form solution to this integrated guidance and control problem based on approximations to the Hamilton-Jacobi-Bellman equation. Finally, the performance of designed algorithm is verified via numerical simulation, which shows the feasibility and realizability of the proposed method. © 2015 IEEE. Source

Xing K.,University of Sichuan | Xing K.,Xichang Satellite Launch Center | Yin Y.,University of Sichuan | Huang Y.,University of Sichuan | Gao Y.,University of Sichuan
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2011

In communication networks, the transmission of coordinated universal time (UTC) is always influenced by delay, hence the accuracy is reduced. In this paper, a correction method based on Kalman filter has been proposed. The delay of networks is divided into three parts, which include fixed delay, jitter delay and burst delay. Kalman filter is employed to reduce the jitter delay, while a tracking door is used for burst delay reduction. Therefore, the delay of networks will approach to the fixed delay and the accuracy is improved. In order to verify the accuracy improvement effect of Kalman filter, the SimEvents expansion module in MATLAB is used to build a terminal-to-terminal computer network transmission model. When the algorithm works steadily, the accuracy of the estimated time delay can be improved by 100 times compared with the measured time delay. A real-time test platform was designed in LabVIEW, which embeds the MATLAB program. Real-time communication network delay was obtained and then filtered. Results indicate that the proposed correction method is effective through the verification of the actual data in both wireless and cable networks. Source

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