检索结果-南通市图书馆

EVALUATION OF POWER SPECTRAL DENSITY OF PASSIVE INTERMODULATION DISTORTION IN HIGH-POWER communication satellite SYSTEMS

在线全文

学校读者我要写书评

暂无评论

引用

Journal of Electronics(China) 2005年第2期22卷 181-184页

作者： ZhangShiquan GeDebiao PhysicsDepartment XidianUniversityXi＇an710071China PhysicsDepartment XidianUniversityXi＇an710071China／／TheArmedPoliceCollegeofEngineeringXi＇an710086China

In order to analyze the deleterious effects of Passive InterModulation (PIM) on high power communication satellite systems, the basic concept of PIM is introduced, and an equation for the power spectral density of the n-th order PIM distortion insuch systems is derived by applying flat signal-power spectrum assumption and Fourier transform method. It is indicated that PIM level generally decreases with order and the lowest frequency receive channel in the receive band is the channel of most affected by PIM interference.

关键词： Passive InterModulation(PIM) Power spectral density Fourier transform communication satellite

DOA estimation for attitude determination on communication satellites

在线全文

学校读者我要写书评

暂无评论

引用

Chinese Journal of Aeronautics 2014年第3期27卷 670-677页

作者： Yang Bin He Feng Jin Jin Xiong Huagang Xu Guanghan School of Electronic and Information Engineering Beihang University School of Aerospace Tsinghua University

In order to determine an appropriate attitude of three-axis stabilized communication satellites, this paper describes a novel attitude determination method using direction of arrival （DOA） estimation of a ground signal source. It differs from optical measurement, magnetic field measurement, inertial measurement, and global positioning system （GPS） attitude determination. The proposed method is characterized by taking the ground signal source as the attitude reference and acquiring attitude information from DOA estimation. Firstly, an attitude measurement equation with DOA estimation is derived in detail. Then, the error of the measurement equation is analyzed. Finally, an attitude determination algorithm is presented using a dynamic model, the attitude measurement equation, and measurement errors. A developing low Earth orbit （LEO） satellite which tests mobile communication technology with smart antennas can be stabilized in three axes by corporately using a magnetometer, reaction wheels, and three-axis magnetorquer rods. Based on the communication satellite, simulation results demonstrate the effectiveness of the method. The method could be a backup of attitude determination to prevent a system failure on the satellite. Its precision depends on the number of snapshots and the input signal-to-noise ratio （SNR） with DOA estimation.

关键词： Attitude determination communication satellite Direction of arrival (DOA) estimation Low Earth orbit (LEO) Smart antennas

Deploying process modeling and attitude control of a satellite with a large deployable antenna

在线全文

学校读者我要写书评

暂无评论

引用

Chinese Journal of Aeronautics 2014年第2期27卷 299-312页

作者： Zhigang Xing Gangtie Zheng School of Aerospace Tsinghua University

Modeling and attitude control methods for a satellite with a large deployable antenna are studied in the present paper. Firstly, for reducing the model dimension, three dynamic models for the deploying process are developed, which are built with the methods of multi-rigid-body dynam- ics, hybrid coordinate and substructure. Then an attitude control method suitable for the deploying process is proposed, which can keep stability under any dynamical parameter variation. Subse- quently, this attitude control is optimized to minimize attitude disturbance during the deploying process. The simulation results show that this attitude control method can keep stability and main- tain proper attitude variation during the deploying process, which indicates that this attitude con- trol method is suitable for practical applications.

关键词： Attitude control communication satellite Deploying process modeling Disturbance rejection Large deployable antenna