National Key Laboratory of Information Control Technology for Communication System

Jiaxing, China

National Key Laboratory of Information Control Technology for Communication System

Jiaxing, China
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Xia M.,Xidian University | Xia M.,Xi'an University of Science and Technology | Yang X.-N.,National Key Laboratory of Information Control Technology for Communication System
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2012

Due to the effect on clutter suppression, Doppler parameters estimation and target focus imaging, motion error compensation is a key technology to bistatic synthetic aperture radar-ground moving target indication (SAR-GMTI). An effective method of motion error analysis and compensation is presented based on the characters of spaceborne-airborne bistatic systems. According to the spaceborne-airborne bistatic SAR-GMTI signal geometry, the influence of error on the parameters of moving target is deduced, and the corresponding compensation factors are also proposed. Especially for the cases when relief and squint cannot be ignored, an offset error compensation is analyzed and an effective compensation is given. Finally, the simulation results show the effectiveness of the method.


Xia M.,Xi'an University of Science and Technology | Yang X.-N.,National Key Laboratory of Information Control Technology for Communication System
Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China | Year: 2013

Target acceleration of SAR moving target detection results in three-phase, and affects stationary target suppression and the precision of parameter estimation. Aiming at this problem, a parameter estimation method based on three-phase compensation is proposed. According to the analysis of signal model, phase compensation is achieved by dechirp and one-dimensional search in time-chirp distribution. After the phase compensation, in order to overcome potential problem of target loss caused by peak overlap in time-frequency distribution, an improved FrFT is employed for parameter estimation and the method is given in detail. Finally, the computer simulation confirms the correctness and validity of the method.


Zhang H.-F.,University of Electronic Science and Technology of China | Zhang H.-F.,National Key Laboratory of Information Control Technology for Communication System | Li L.-P.,University of Electronic Science and Technology of China | Yang X.-N.,National Key Laboratory of Information Control Technology for Communication System | Li W.-C.,University of Electronic Science and Technology of China
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2011

Independent component analysis (ICA) is one of the most important methods for blind source separation (BSS), in which the pre-whitening procedure of the observed signals plays an important role. Usually, principle component analysis (PCA) is employed for this preprocessing task. In practice, the observed signals of a passive radar system are usually corrupted by strong noise and outliers, which greatly reduces the performance of BSS methods. However, this problem is rarely taken into account in the whitening step of traditional BSS methods. We focus on this problem and propose a new whitening framework for noisy BSS. The idea is that the noise variance is removed from the covariance matrix of the observed signals before whitening. The experiments show that the BSS performance is greatly improved using the proposed whitening framework.


Xia M.,Xidian University | Yang X.-N.,National Key Laboratory of Information Control Technology for Communication System
Yuhang Xuebao/Journal of Astronautics | Year: 2011

Aiming at the influence of fast moving target with acceleration on imaging and parameter estimation, a novel method for moving target detection with three-channel is proposed based on refocusing image. After the moving target echo is analyzed, the general two-order keystone transform is used to correct range curve for clutter suppression result. Time-frequency analysis is employed to construct phase compensation function and to correct the residual range walk. Finally azimuth Fourier transform is performed to get the image. Moving target parameters can be obtained by using the interferometric processing technique. Simulation results show the validity of the method.


Xia M.,Xidian University | Yang X.,National Key Laboratory of Information Control Technology for Communication System
Zhongguo Kongjian Kexue Jishu/Chinese Space Science and Technology | Year: 2011

For residual clutter caused by system errors and motion errors in spaceborne SAR-GMTI with three-channel when using displaced phase center antenna(DPCA) technology to suppress clutter, a novel method of detection and position for moving target was presented based on error compensation. Aiming at elimination of residual clutter, errors were analyzed in detail and corresponding compensation functions were derived. After compensation, DPCA and interferometric processing were applied to cultter suppression and moving target position.


Luo M.,University of Science and Technology of China | Luo M.,National Key Laboratory of Information Control Technology for Communication System | Gan L.,University of Science and Technology of China | Li L.,University of Science and Technology of China
Journal of Information and Computational Science | Year: 2012

In modern wireless communication systems, one of the most promising techniques to improve the communication reliability and rate relies on the use of Multiple Input Multiple Output (MIMO) systems in association with Space-time Block Code (STBC). The recognition of communication parameters is a key step to decode the signals intercepted by receiver in a MIMO-STBC system. A new algorithm is developed to identify STBCs by adopting the Frobenius norms of space-time correlations matrices as features in a high dimensional space when the Channel State Information (CSI) is unavailable. In this high dimensional feature space, STBCs possess better divisibility than the methods in literature. A classifier based on Support Vector Machine (SVM) is trained to recognize STBCs. Simulations show that our classifier works well in the environments of short samples, limited number of receiver antennas and various modulations; the new method can recognize some STBCs which can not be distinguished by the algorithms in literatures; our method has better performance of correct recognition probability than these algorithms. © 2012 by Binary Information Press.


Xia M.,Xidian University | Yang X.-N.,National Key Laboratory of Information Control Technology for Communication System
Yuhang Xuebao/Journal of Astronautics | Year: 2012

Based on the multiple-input multiple-output synthetic aperture radar, an approach with dual-satellites dual frequency for detection, imaging and parameter estimation of the ground fast moving target is proposed. General two-order Keystone transform is employed to eliminate range migration. For the Doppler ambiguity of fast moving target, modified discrete Chirp-Fourier transform and least waveform entropy search are applied to Doppler parameters estimation. The actual target velocity can be obtained by searching of different frequency data, and a fast data search method with little calculation is also presented. Finally, simulation results show the effectiveness of the method.

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