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Synthetic Aperture Positioning: A Review
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作者 Guangcai Sun Wenlong Dong +1 位作者 Yuqi Wang Mengdao Xing 《Journal of Beijing Institute of Technology》 EI CAS 2024年第2期89-102,共14页
Obtaining precise position of interested emitters passively has wide applications in both civilian and military fields.Different from traditional parameter measurement and direct position determination(DPD)method,rece... Obtaining precise position of interested emitters passively has wide applications in both civilian and military fields.Different from traditional parameter measurement and direct position determination(DPD)method,recently a new passive localization method based on synthetic aper-ture technique,named synthetic aperture positioning(SAP),has been proposed.The method com-pensates for the nonlinear phase produced by relative motion between the moving platform and the emitter,achieving coherent summation of intercepted signals.The SAP can obtain high-resolution and high-precision localization results at a low signal-to-noise ratio.This paper summarizes the research progress of SAP,including localization principles,spaceborne applications,and application scope analysis.Besides,the possible future outlook of SAP is considered. 展开更多
关键词 passive localization synthetic aperture positioning coherent processing
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Ultrawide-band radar imagery from multiple incoherent frequency subband measurements 被引量:8
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作者 Xiaojian Xu Jia Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第3期398-404,共7页
The problem of combined radar imagery from multiple sparse frequency subbands initially incoherent to each other is of practical importance for radar target discrimination.A new coherent processing technique based on ... The problem of combined radar imagery from multiple sparse frequency subbands initially incoherent to each other is of practical importance for radar target discrimination.A new coherent processing technique based on probability density analysis of the subband data is proposed,which is applicable for radar imaging from measurements of two or more initially incoherent radar subbands.The coherence parameters for both amplitude and phase are obtained by combining modern spectral analysis with probability density estimation.The major advantage of the proposed technique lies in that it enables much more robust cohering for the sparse subband data of real-world complex targets. 展开更多
关键词 radar imagery coherent processing SUBBAND spectral analysis.
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Long term integration of radar signals with unknown Doppler shift for ubiquitous radar 被引量:4
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作者 Qinglong Bao Zengping Chen Yue Zhang Jian Yang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第2期219-227,共9页
Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in "pop-up" targets in clutter to long-range target... Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in "pop-up" targets in clutter to long-range targets impacts selection of waveform parameters. The coherent processing interval (CPI) must be long enough to achieve a certain signal-to-noise ratio (SNR) that ensures the efficiency of detection. The condition of detection in the case of low SNR is analyzed, and three different cases that would occur during integration are discussed and a method to determine the CPI is presented. The simulation results show that targets detection with SNR as low as -26 dB in the experimental system can possibly determine the CPI. 展开更多
关键词 ubiquitous radar low signal-to-noise ratio (SNR) coherent processing interval (CPI) coherent integration non-coherent integration.
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Fast direction of arrival algorithm based on vector-sensor arrays using wideband sources 被引量:1
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作者 孙国仓 惠俊英 陈阳 《Journal of Marine Science and Application》 2008年第3期195-199,共5页
An acoustic vector sensor(AVS)can capture more information than a conventional acoustic pressure sensor(APS).As a result,more output channels are required when multiple AVS are formed into arrays,making processing the... An acoustic vector sensor(AVS)can capture more information than a conventional acoustic pressure sensor(APS).As a result,more output channels are required when multiple AVS are formed into arrays,making processing the data stream computationally intense.This paper proposes a new algorithm based on the propagator method for wideband coherent sources that eliminates eigen-decomposition in order to reduce the computational burden.Data from simulations and lake trials showed that the new algorithm is valid:it resolves coherent sources,breaks left/right ambiguity,and allows inter element spacing to exceed a half-wavelength. 展开更多
关键词 acoustic vector sensor propagator method coherent processing fast algorithm
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Weak GPS L1 Signal Acquisition Based on BPDC 被引量:3
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作者 曾庆喜 唐琳琳 +1 位作者 王庆 陈小惠 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2014年第3期331-337,共7页
It is difficult to achieve accurate acquisition of weak global positioning system( GPS) signals with traditional methods. A weak signal acquisition strategy based on block processing and differentially coherent( BPDC)... It is difficult to achieve accurate acquisition of weak global positioning system( GPS) signals with traditional methods. A weak signal acquisition strategy based on block processing and differentially coherent( BPDC) is put forward after analyzing the advantages and disadvantages of coherent and non-coherent integration algorithms. Code phase parallel search of the pre-coherent integration is conducted by using fast Fourier transform( FFT),and the results are then differential coherent processed and block processed. BPDC method reduces computation cost compared with coherent and noncoherent( CNC) algorithm. The performance of the two algorithms is also compared based on simulated signals. The result shows that the noise suppression effect of BPDC algorithms is superior to that of traditional CNC algorithm,and the superiority of BPDC is more apparent with the reduction of carrier to noise ratio( CNR). In the case that the pre-coherent integration length is 4 ms and CNR is reduced to 28 dB-Hz,CNC algorithm cannot yet acquire signal correctly while BPDC has well acquisition performance. Therefore,for weak GPS signal acquisition,BPDC algorithm can acquire the signal with lower CNR and has better acquisition property. 展开更多
关键词 block processing and differentially coherent(BPDC) coherent and non-coherent(CNC) weak GPS signals
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The wide-band coherent signal-subspace processing based on propagator method
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作者 ZHI Wanjun LI Zhishun (College of Marine Engineering, Northwestern Polytechnical University Xi’an 710072) 《Chinese Journal of Acoustics》 2000年第4期363-370,共8页
The narrow band propagator method is introduced to the wide-band coherent signal-subspace processing in the direction finding problem. A new technique that needs no direction pre-estimation or matrix decomposition is ... The narrow band propagator method is introduced to the wide-band coherent signal-subspace processing in the direction finding problem. A new technique that needs no direction pre-estimation or matrix decomposition is presented to compute the focusing matrices, so the focusing matrices are robust and the computation,.is simple. Then, the propagator method is extended to the focused covariance matrix to find the directions of the sources. The whole estimation process avoids the rather expensive matrix decomposition, and the results of simulations proved the effectiveness of the new method. 展开更多
关键词 CSM The wide-band coherent signal-subspace processing based on propagator method DOA MPM
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Quantum coherence preservation of atom with a classical driving field under non-Markovian environment
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作者 高德营 高强 夏云杰 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期89-96,共8页
The exact dynamics of an open quantum system consisting of one qubit driven by a classical driving field is investigated. Our attention is focused on the influences of single-and two-photon excitations on the dynamics... The exact dynamics of an open quantum system consisting of one qubit driven by a classical driving field is investigated. Our attention is focused on the influences of single-and two-photon excitations on the dynamics of quantum coherence and quantum entanglement. It is shown that the atomic coherence can be improved or even maintained by the classical driving field, the non-Markovian effect, and the atom-reservoir detuning. The interconversion between the atomic coherence and the atom-reservoir entanglement exists and can be controlled by the appropriate conditions. The conservation of coherence for different partitions is explored, and the dynamics of a system with two-photon excitations is different from the case of single-photon excitation. 展开更多
关键词 quantum coherence non-Markovian process classical driving field
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Preservation of Quantum Coherence for Gaussian-State Dynamics in a Non-Markovian Process
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作者 Jun Wen Guan-Qiang Li 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第6期1-5,共5页
Coherence is a key resource in quantum information science.Exactly understanding and controlling the variation of coherence are vital for implementation in realistic quantum systems.Using P-representation of density m... Coherence is a key resource in quantum information science.Exactly understanding and controlling the variation of coherence are vital for implementation in realistic quantum systems.Using P-representation of density matrix,we obtain the analytical solution of the master equation for the classical states in the non-Markovian process and investigate the coherent dynamics of Gaussian states.It is found that quantum coherence can be preserved in such a process if the coupling strength between system and environment exceeds a threshold value.We also discuss the characteristic function of the Gaussian states in the non-Markovian process,which provides an inevitable bridge for the control and operation of quantum coherence. 展开更多
关键词 Preservation of Quantum Coherence for Gaussian-State Dynamics in a Non-Markovian Process
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A combined signal processing approach against coherent interference with pressure and particle velocity
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作者 HUI Junying, LI Chunxu, LIANG Guolong, LIU Hong (Harbin Engineering University Harbin 150001) 《Chinese Journal of Acoustics》 2001年第3期193-202,共10页
Comparing with traditional underwater acoustic system which only utilizes pressure information, combine sensor system processes pressure together with particle velocity information of sound field. More information ce... Comparing with traditional underwater acoustic system which only utilizes pressure information, combine sensor system processes pressure together with particle velocity information of sound field. More information certainly brings nicer processing result. By using spatial directional information collected by combine sensor, the Coherent Interference Energy Suppress (CIES) technology, which can effectively suppress coherent interference and detect linear spectrum signal and wide-band continuous-spectrum signal as well, is presented. Current research has shown favorite result, and further research is going on. 展开更多
关键词 A combined signal processing approach against coherent interference with pressure and particle velocity
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