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Time filter

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Lei C.,China Academy of Electronic and Information Technology | Zhang J.,Beihang University | Gao Q.,Beihang University
IET Signal Processing | Year: 2014

The detection of sparse signals against background noise is difficult since the information in the signal is only carried by a small portion of it. Prior information is usually assumed to ease detection. This study considers the general unknown and arbitrary sparse signal detection problem when no prior information is available. Under a Neyman-Pearson hypothesis-testing problem model, a new detection scheme referred to as the likelihood ratio test with sparse estimation (LRT-SE) is proposed. The SE technique from the compressive sensing theory is incorporated into the LRT-SE to achieve the detection of sparse signals with unknown support sets and arbitrary non-zero entries. An analysis of the effectiveness of LRT-SE is first given in terms of the characterisation of the conditions for the Chernoff-consistent detection. A large deviation analysis is then given to characterise the error exponent of LRT-SE with respect to the signal-to-noise ratio and the angle between the sparse signal and its estimate. Numerical results demonstrate superior detection performance of the proposed scheme over existing asymptotically optimal sparse detectors for finite signal dimensions. In addition, the simulation shows that the error probability of the proposed scheme decays exponentially with the number of observations. © The Institution of Engineering and Technology 2014. Source


Zhang W.,University of Electronic Science and Technology of China | Zhang W.,China Academy of Electronic and Information Technology | Liu Z.,China Academy of Electronic and Information Technology | Liu Z.,Beijing Institute of Technology
MMWCST 2013 - Proceedings of 2013 International Workshop on Microwave and Millimeter Wave Circuits and System Technology | Year: 2013

How to generate a waveform that can realize communication of data and detection of radar at the same time is a key technology of radar-communications integration. In this paper, with the use of existing theory that proposes a novel compatible waveform by modulation LFM signal by MSK, the digital orthogonal modulation MSK-LFM signal is realized on FPGA; and the high-speed DAC and multi-channel synthesis are applied to directly generate wave at UHF-band wave. The algorithms and hardware of the modulator are discussed in detail and the test data is also given. © 2013 IEEE. Source


Zhang W.,University of Electronic Science and Technology of China | Zhang W.,China Academy of Electronic and Information Technology | Cao C.,China Academy of Electronic and Information Technology
2013 International Conference on Communications, Circuits and Systems, ICCCAS 2013 | Year: 2013

Through the calculating of the received clutter power distribution of airborne early warning radar of different PRF based on mean sidelobe level, also considering the restrict between PRF, the main beam clutter block and the coherent integration, this paperbuilds the relation between PRF and the detected area percentage. The optimized PRF of different sidelobe level and landform is found by this model, and an example of designing the multi PRF under M/N criterion is also given. © 2013 IEEE. Source


Li B.-Q.,China Academy of Electronic and Information Technology | Zhang S.,China Academy of Electronic and Information Technology | Wang Z.-W.,China Academy of Electronic and Information Technology | Xu S.-F.,China Academy of Electronic and Information Technology
Beijing Ligong Daxue Xuebao/Transaction of Beijing Institute of Technology | Year: 2015

Different multimedia services have different requirement of delay and jitter, it is essential to select an appropriate schedule algorithm to meet the quality of service (QoS) of different multimedia services. Firstly, the impact on performance of delay and fairness of WRR and WFQ algorithm was studied; then, an enhanced WRR (E-WRR) algorithm based on packet length and queue weight was proposed. Simulation results show that when the packet length in different queues are same, almost same delay performance can be approached by both WRR and WFQ; when the packet length in different queues are different, the delay requirement of higher priority queue cannot be approached with WRR algorithm. However, the delay performance of proposed E-WRR algorithm can be close in upon WFQ algorithm, which can guarantee the delay requirement of higher priority queue, and greatly reduce the calculation complexity of schedule algorithm. ©, 2015, Beijing Institute of Technology. All right reserved. Source


Zhao H.-Y.,Research Institutes of Electronic Science and Technology | Zhao H.-Y.,China Academy of Electronic and Information Technology | Cai A.-H.,Research Institutes of Electronic Science and Technology | Cai A.-H.,China Academy of Electronic and Information Technology | Zhang S.-S.,China Academy of Electronic and Information Technology
MMWCST 2013 - Proceedings of 2013 International Workshop on Microwave and Millimeter Wave Circuits and System Technology | Year: 2013

Locating remote slow sea-surface targets with airborne radar is a problem of the non-linear and non-Gaussian state estimation, resulting in the deviation of the target location and the track jitter when dealing with tradition Kalman filter. In this paper, adaptive particle filter (APF) is used to solve the ship tracking problem under glint noise. The algorithm can choose the number of particles based on KLD-Sampling, which is efficient and has smaller time consumption. Computer simulation proves that adapti ve particle filter can track quickly sea-surface targets under glint noise, and the tracking performance is superior to that of standard particle filter (PF), so APF is practically valuable for engineering use. © 2013 IEEE. Source

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