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Mao Y.-X.,Chinese Academy of Sciences | Mao Y.-X.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Ma J.-Y.,Chinese Academy of Sciences | Zhang J.,Chinese Academy of Sciences | Song Y.-Z.,Chinese Academy of Sciences
Yuhang Xuebao/Journal of Astronautics | Year: 2014

In a satellite launch task using spring separation mode, the satellite obtains a velocity increment produced from the separating force of spring, data of two segments before and after the epoch of satellite-rocket separation are not in the same orbit, and can't be used to calculate the orbit together by using traditional method. To solve the problem, a new method, improved method of perturbed initial orbit determination based on Unit Vector Method, is proposed to solve a position vector and two velocity vectors simultaneously in this paper. The results of simulated and measured data show that the method can realize combined orbit determination by using the measured data of two different orbits before and after the satellite-rocket separation. Because the orbit determination data is increased, the accuracy of initial orbit determination in injection phase is also improved. ©, 2014, China Spaceflight Society. All right reserved. Source


Qin H.,Xidian University | Han J.,Xidian University | Yan X.,Xidian University | Zeng Q.,Xidian University | And 4 more authors.
Infrared Physics and Technology | Year: 2016

Infrared small moving target detection is one of the crucial techniques in infrared search and tracking systems. This paper presents a novel small moving target detection method for infrared image sequence with complicated background. The key points are given as follows: (1) since target detection mainly depends on the incoherence between target and background, the proposed method separate the target from the background according to the morphological feature diversity between target and background; (2) considering the continuity of target motion in time domain, the target trajectory is extracted by the RX filter in random projection. The experiments on various clutter background sequences have validated the detection capability of the proposed method. The experimental results show that the proposed method can robustly provide a higher detection probability and a lower false alarm rate than baseline methods. © 2016 The Authors. Source


Qu Y.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Cong B.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control
Proceedings of the International Astronautical Congress, IAC | Year: 2013

Ship rolling affects greatly the stable tracking of the space tracking ship's instrumentation radar, especially of the unified X-band system, whose beam is very narrow and object acquisition and stable tracking becomes much more difficult in dynamic environment of the sea. This paper proposes and elaborates various techniques to overcome this challenge and to get quick acquisition, improve isolation of ship rolling, reduce dynamic lag, and enable the shipboard narrow-beam system to track stably with required accuracy. Copyright© (2013) by the International Astronautical Federation. Source


Li K.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Lin X.-L.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Hu X.-J.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Cai Z.-G.,Xian Jiaotong University
Journal of Donghua University (English Edition) | Year: 2015

To overcome the problem that a single feature can not reflect the state of machinery in different stages, a method of vibration feature fusion based on self-organizing map (SOM) is presented. Minimum quantization error (MQE) is obtained unsupervised based on SOM network. And trend information of the MQE curve is extracted by the wavelet packet to enhance state differentiating. Experimental flat is designed for bearing accelerating fatigue. And experimental results show that the method of vibration feature fusion based on SOM can reflect the state of machinery in different stages effectively. Copyright © 2015 Editorial Department of Journal of Donghua University. All rights reserved. Source


Cong B.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Xi Z.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Wang J.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control | Wu Y.,Joint Laboratory of Flight Vehicle Ocean Based Measurement and Control
Proceedings of the International Astronautical Congress, IAC | Year: 2013

Space tracking ship is still playing an important role in Chinese TT&C (Telemetry, Tracking and Command) network. To meet the needs of future space programs, the new-generation space tracking ships were built, which adopted many new and advanced techniques. This paper introduces the TT&C system and ship attitude and positioning system of the new-generation space tracking ships. Limited room, adversary environment and ship rolling are the main challenges which must be overcome and thus the design is much different from those of land- based stations. The concept of integration and reuse prevails in the whole system and is elaborated in this paper. The error of ship positioning and attitude contributes greatly to the final result, so various techniques are exploited to improve the accuracy. Future research directions are also addressed and possible approaches for future challenges are discussed. Copyright© (2013) by the International Astronautical Federation. Source

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