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Resource saving based dwell time allocation and detection threshold optimization in an asynchronous distributed phased array radar network

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Chinese Journal of Aeronautics 2023年第11期36卷 311-327页

作者： Haowei ZHANG weijian liu Xiao YANG Air and Missile Defense College Air Force Engineering UniversityXi’an 710051China Air Force Early Warning Academy Wuhan 410039China Chinese People’s Liberation Army 93557 Troops Shijiazhuang 050000China

The resource optimization plays an important role in an asynchronous Phased Array Radar Network(PARN)tracking multiple targets with Measurement Origin Uncertainty(MOU),i.e.,considering the false alarms and missed detections.A Joint Dwell Time Allocation and Detection Threshold Optimization(JDTADTO)strategy is proposed for resource saving in this *** Predicted Conditional Cramér-Rao Lower Bound(PC-CRLB)with Bayesian Detector and Amplitude Information(BD-AI)is derived and adopted as the tracking performance *** optimization model is formulated as minimizing the difference between the PC-CRLBs and the tracking precision thresholds under the constraints of upper and lower bounds of dwell time and false alarm *** is shown that the objective function is nonconvex due to the Information Reduction Factor(IRF)brought by the MOU.A cyclic minimizer-based solution is proposed for problem *** results confirm the flexibility and robustness of the JDTADTO strategy in both sufficient and insufficient resource *** results also reveal the effectiveness of the proposed strategy compared with the strategies adopting the BD without detection threshold optimization and amplitude information.

关键词： Asynchronous data fusion Bayesian detector Phased Array Radar Network(PARN) Predicted Conditional CramE´R-Rao Lower Bound(PC-CRLB) Resource management

A rescaling algorithm for multi-relaxation-time lattice Boltzmann method towards turbulent flows with complex configurations

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Applied Mathematics and Mechanics(English Edition) 2023年第9期44卷 1597-1612页

作者： Haoyang LI weijian liu Yuhong DONG Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai UniversityShanghai 200072China Shanghai Frontier Science Center of Mechanoinformatics Shanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Understanding and modeling flows over porous layers are of great industrial *** accurately solve the turbulent multi-scale flows on complex configurations,a rescaling algorithm designed for turbulent flows with the Chapman-Enskog analysis is *** mesh layout and the detailed rescaling procedure are also *** numerical simulations(DNSs)for a turbulent channel flow and a porous walled turbulent channel flow are performed with the three-dimensional nineteen-velocity(D3Q19)multiple-relaxation-time(MRT)lattice Boltzmann method(LBM)to validate the accuracy,adaptability,and computational performance of the present rescaling *** results,which are consistent with the previous DNS studies based on the finite difference method and the LBM,demonstrate that the present method can maintain the continuity of the macro values across the grid interface and is able to adapt to complex *** reasonable time consumption of the rescaling procedure shows that the present method can accurately calculate various turbulent flows with multi-scale and complex configurations while maintaining high computational efficiency.

关键词： slattice Boltzmann method(LBM) direct numerical simulation(DNS) rescaling algorithm complex configuration

Adaptive detection based on orthogonal partition of the primary and secondary data

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Journal of Systems Engineering and Electronics 2014年第1期25卷 34-42页

作者： weijian liu Wenchong Xie Yongliang Wang College of Electronic Science and Engineering National University of Defense Technology Air Force Early Warning Academy

A novel adaptive detection scheme both for point-like and distributed targets in the presence of Gaussian disturbance in the partial y homogeneous environment （PHE） is proposed. The novel detection scheme is based on the orthogonal projection technique. Both the case of known covariance matrix structure and the case of unknown covariance matrix structure are con-sidered. For the former case, the closed-form statistical pro-perty of the novel detectors is derived. When the covariance matrix is unknown, the corresponding detectors have higher probabilities of detection （PDs） than their natural competitors. Moreover, they ensure constant false alarm rate （CFAR） property.

关键词： partially homogeneous environment (PHE) orthogo-nal partition orthogonal projection.

A robust joint frequency spectrum and power allocation strategy in a coexisting radar and communication system

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Chinese Journal of Aeronautics 2024年第10期37卷 393-409页

作者： Haowei ZHANG weijian liu Qun ZHANG Taiyong FEI Air and Missile Defense School Air Force Engineering UniversityXi’an 710051China Air Force Early Warning Academy Wuhan 410039China Information and Navigation School Air Force Engineering UniversityXi’an 710082China

The resource allocation technique is of great significance in achieving frequency spectrum coexistence in Joint Radar-Communication(JRC) systems, by which the problem of radio frequency spectrum congestion can be well alleviated. A Robust Joint Frequency Spectrum and Power Allocation(RJFSPA) strategy is proposed for the Coexisting Radar and Communication(CRC)system. Specifically, we consider the uncertainty of target Radar Cross Section(RCS) and communication channel gain to formulate a bi-objective optimization model. The joint probabilities that the Cramér-Rao Lower Bound(CRLB) of each target satisfying the localization accuracy threshold and the Communication Data Ratio(CDR) of each user satisfying the communication threshold are simultaneously maximized, under the constraint of the total power budget. A Three-Stage Alternating Optimization Method(TSAOM) is proposed to obtain the Best-Known Pareto Subset(BKPS) of this problem, where the frequency spectrum, radar power, and communicator power are allocated using the greedy search and standard convex optimization methods, respectively. Simulation results confirm the effectiveness of the proposed RJFSPA strategy, compared with the resource allocation methods in a uniform manner and that ignores the uncertainties. The efficiency of the TSAOM is also verified by the comparison with the exhaustive search-based method.

关键词： Radar and communication system Bi-objective optimization Resource allocation Cramér-Rao lower bound Communication data ratio

Multichannel adaptive signal detection: basic theory and literature review

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Science China(Information Sciences) 2022年第2期65卷 5-44页

作者： weijian liu Jun liu Chengpeng HAO Yongchan GAO Yong-Liang WANG Wuhan Electronic Information Institute Department of Electronic Engineering and Information Science University of Science and Technology of China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences School of Electronic Engineering Xidian University

Multichannel adaptive signal detection uses test and training data jointly to form an adaptive detector to determine whether a target exists. The resulting adaptive detectors typically possess constant false alarm rate(CFAR) properties; thus, no additional CFAR processing is required. In addition, a filtering process is also not required because the filtering function is embedded in the adaptive detector. Adaptive detection typically exhibits better detection performance than the filtering-then-CFAR detection *** has been approximately 35 years since the first multichannel adaptive detector was proposed by Kelly in 1986. However, there are few overview articles on this topic. Thus, in this study, we present a tutorial overview of multichannel adaptive signal detection with an emphasis on the Gaussian background. We discuss the main design criteria for adaptive detectors, investigate the relationship between adaptive detection and filtering-then-CFAR detection techniques, investigate the relationship between adaptive detectors and adaptive filters, summarize typical adaptive detectors, present numerical examples, provide a comprehensive literature review, and discuss potential future research tracks.

关键词： constant false alarm rate multichannel signal signal mismatch statistical distribution subspace signal

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Polycyclic aromatic hydrocarbons in ambient air,surface soil and wheat grain near a large steel-smelting manufacturer in northern China

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Journal of Environmental Sciences 2017年第7期29卷 93-103页

作者： weijian liu Yilong Wang Yuanchen Chen Shu Tao Wenxin liu Laboratory for Earth Surface Processes College of Urban and Environmental SciencesPeking UniversityBeijing 100871China

The total concentrations and component profiles of polycyclic aromatic hydrocarbons（PAHs） in ambient air,surface soil and wheat grain collected from wheat fields near a large steel-smelting manufacturer in Northern China were *** on the specific isomeric ratios of paired species in ambient air,principle component analysis and multivariate linear regression,the main emission source of local PAHs was identified as a mixture of industrial and domestic coal combustion,biomass burning and traffic *** total organic carbon（TOC） fraction was considerably correlated with the total and individual PAH concentrations in surface *** total concentrations of PAHs in wheat grain were relatively low,with dominant low molecular weight constituents,and the compositional profile was more similar to that in ambient air than in *** with more significant results from partial correlation and linear regression models,the contribution from air PAHs to grain PAHs may be greater than that from soil PAHs.

关键词： PAHs Ambient air Surface soil Wheat grain Steel-smelting activity

Reduced-rank space-time adaptive detection for airborne radar

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Science China(Information Sciences) 2014年第8期57卷 106-116页

作者： WANG YongLiang liu weijian XIE WenChong ZHAO YingJun Key Research Lab Wuhan Radar Academy College of Electronic Science and Engineering National University of Defense Technology

For airborne radar,there are usually insufficient independent and identically distributed(IID)training data because of geometric considerations and terrain *** rank reduction technique is one of the most effective approaches to circumvent this *** this study,we investigate four reduced-rank spacetime adaptive detectors for airborne radar,namely,the reduced-rank sample-matrix-inversion(RR-SMI),the reduced-rank adaptive matched filter(RR-AMF),the reduced-rank adaptive coherence estimator(RR-ACE),and the reduced-rank generalized likelihood ratio test(RR-GLRT).Their asymptotic analytical probabilities of detection(PD’s)and false alarm(PFA’s)are all *** detectors all asymptotically attain a constant false alarm rate(CFAR).It is shown that these four reduced-rank detectors exhibit detection performance which is better than or comparable to that of two existing reduced-rank detectors,proposed by Reed and Gau(RG1and RG2).Moreover,these four reduced-rank detectors are more robust to change in power of clutter and noise than RG1 and RG2.

关键词： airborne radar constant false alarm rate(CFAR) rank reduction space-time adaptive detection(STAD) space-time adaptive processing(STAP) target detection

Multichannel radar adaptive signal detection in interference and structure nonhomogeneity

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Science China(Information Sciences) 2017年第11期60卷 221-234页

作者： weijian liu Hui HAN Jun liu Hongli LI Kai LI Yong-Liang WANG Air Force Early Warning Academy State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National Laboratory of Radar Signal Processing Xidian University Collaborative Innovation Center of Information Sensing and Understanding Xidian University School of Electronic Information Wuhan University

In this paper, we consider the problem of multichannel radar signal detection in interference and structure nonhomogeneity. The interference is often caused by electromagnetic countermeasure(ECM) systems or industrial activity, while the nonhomogeneity usually arises because of rapid variations in terrain or radar antenna structure. We propose three adaptive detectors according to three common criteria of detector design, namely, the generalized likelihood ratio test(GLRT), Rao test, and Wald test. Extensive performance comparisons are conducted under different scenarios. It is shown that when the nonhomogeneity is severe, the detector devised according to the GLRT achieves the best detection performance. In other scenarios, the detector designed according to the Wald test may be the best choice, which has the highest probability of detection.

关键词： adaptive detection generalized likelihood ratio test heterogeneity interference multichannel sig nal nonhomogeneity Rao test Wald test

GLRT-based generalized direction detector in partially homogeneous environment

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Science China(Information Sciences) 2019年第10期62卷 211-213页

作者： weijian liu Fei GAO Yuwen LUO Jun liu Yongliang WANG Wuhan Electronic Information Institute Xi'an Institute of Space Radio Technology Department of Electronic Engineering and Information Science University of Science and Technology of China

Dear editor,Target detection is a basic function for any radar system [1]. For the problem of generalized direction detection, two adaptive detectors were proposed in [2], according to the generalized likelihood ratio test (GLRT). For the above problem,under the signal-presence hypothesis, the rows and columns of a rank-one matrix-valued signal belong to known subspaces; however, the corresponding coordinates are unknown. The resulting detectors

关键词： GLRT-based generalized direction detector in partially homogeneous environment pro NK SD