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Moving Target Coherent Integration Method Based on TRCM-KT for UAV-Mounted Through-the-wall Radar

IEEE Signal Processing Letters 2025年 32卷 1775-1779页

作者： Qu, Xiaodong Sun, Xiaolong Liu, Feiyang Zhang, Hao Yang, Xiaopeng Beijing Institute of Technology School of Information and Electronics Beijing100081 China Beijing Institute of Technology Key Laboratory of Electronic and Information Technology in Satellite Navigation Beijing100081 China Jiaxing Research Center of Beijing Institute of Technology Jiaxing314000 China

Moving target detection in through-the-wall scenario can be achieved by utilizing unmanned aerial vehicle (UAV) radar. However, considering indoor human target detection, the distance between the radar and the moving target is relatively short, and the ratio of target's velocity to the UAV's velocity varies greatly, which makes the range migration and Doppler phase much more complex and poses huge challenges for coherent integration. To address this issue, this letter proposes a moving target coherent integration method based on time reverse conjugate multiply and keystone transform (TRCM-KT) for UAV-mounted through-the-wall radar. In the proposed method, the reference signal is constructed by azimuthal time reverse and conjugation. Then, by multiplying the echo signal and the reference signal, the second-order range migration and doppler phase terms are eliminated. Next, keystone transform is employed to correct the remained first-order range migration. Finally, the fully coherent integration results can be obtained by performing Fourier transform along the azimuth direction. The effectiveness of the proposed method is verified by both simulation and experiment results. © 1994-2012 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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Robust signal phase tracking in the gnss space-time array processing anti-interference receiver 6

Robust signal phase tracking in the gnss space-time array pr...

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6th International Conference on Geoscience and Remote Sensing Mapping, GRSM 2024

作者： Xie, Yuchen Ni, Shaojie Ma, Ming Xiao, Wei Lei, Chen College of Electronic Science National University of Defense Technology Changsha China Key Laboratory of Satellite Navigation Technology Changsha China

ISBN: (纸本)9781510688018

Electromagnetic interference is one of the most serious threats to satellite navigation receivers, and the most effective countermeasures in the existing research is the space-time array processing (STAP) anti-interference technology. However, the traditional STAP will cause the signal signal phase to deviate, resulting in a decrease in phase tracking accuracy, or even serious consequences such as receiver loop loss. There are three bottleneck problem for the STAP bias correction, including the delay uncertainty in anti-interference filters, the non-ideal nature of the analog devices, and the unclearness of signal direction. Here, we propose a method for modifying the GNSS antenna array receiver’s signal phase deviation. Compared with the traditional algorithms, the proposed algorithm is implemented in a simple way and requires no a priori information. Simulation and 2 types of real data test results show that the proposed algorithm can effectively suppress the signal phase deviation caused by the STAP, and the residual error after the algorithm processing is less than 8°, which improves the receiver's signal phase tracking performance. © 2025 SPIE.

关键词： Antenna arrays

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High-Precision Time Delay Estimation Algorithm Based on Multi-Path Fractional Farrow Structure 24

High-Precision Time Delay Estimation Algorithm Based on Mult...

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3rd International Conference on Signal Processing, Computer Networks and Communications, SPCNC 2024

作者： Song, Jie Zeng, Yejia Lu, Cheng Zhao, Xiaoyu Yu, Yi Sun, Guangfu College of Electronic Science and Technology National University of Defense Technology Hunan Changsha China Key Laboratory of Satellite Navigation Technology Changsha China College of Electronic Science and Technology National University of Defense Technology Key Laboratory of Satellite Navigation Technology Hunan Changsha China Hunan Xinghe Electronics Co. Ltd. Hunan Changsha China

ISBN: (纸本)9798400710834

Interference propagation delay estimation is a key technique for locating interference sources. However, the traditional delay estimation can only be accurate to the sampling interval, or it has its own shortcomings in low complexity and improving the accuracy of delay estimation. In this paper, a high-precision interference delay estimation algorithm based on four-branch Farrow structured fractional delay filter is proposed by combining generalized cross correlation and fractional delay filter. The cross-correlation can be used to estimate the time delay, and the fractional delay filter can realize the non-integer delay and the accurate delay estimation of the interference signal. Under the premise of reducing the processing complexity and ensuring the amplitude-phase characteristics of the filter, the approximation of the ideal fractional delay filter is realized, which breaks the limit of the sampling rate and improves the estimation accuracy of the delay error of interference propagation. The experimental results indicate that with the receiver sampling rate of 25 MHz and the sampling interval of 40 ns, the estimation accuracy of interference propagation delay exceeds 10 ns. © 2024 Copyright held by the owner/author(s).

关键词： Time delay

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Determining geocenter motion using combined ground and spaceborne GPS observations with ambiguity resolution

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Advances in Space Research 2025年第11期75卷 7903-7916页

作者： Guo, Shiwei Fan, Lei Li, Zongnan Fang, Xinqi Huo, Chenshu Shi, Chuang School of Space and Earth Sciences Beihang University Beijing102206 China Key Laboratory of Navigation and Communication Fusion Technology Ministry of Industry and Information Technology Beijing100191 China College of Electronic Science National University of Defense Technology Changsha410005 China School of Electronic and Information Engineering Beihang University Beijing100191 China

Owing to the dense global tracking network and the abundant satellites providing continuous observations, the Global navigation satellite System (GNSS) has the potential to measure geocenter motion. However, the high altitude of GNSS satellites and the estimation of phase ambiguities compromise the quality of the estimated geocenter coordinates (GCC). This study conducted a combined zero-difference processing of ground observations from 98 global stations and spaceborne observations from four low Earth orbiters (LEOs), investigating the impact of integer ambiguity resolution and LEO configuration on GPS-derived GCC estimates. The ambiguity resolution in the double-difference mode between ground stations and one LEO can significantly improve the observability of GCC estimates, reducing the formal errors by 69.4 %, 69.4 % and 55.0 % for the X, Y and Z components, respectively. The faster relative motion between LEO and GPS satellites contributes to a faster change of tracking geometry. Integrating four LEOs into ground network, the formal errors of GCC parameters are reduced by 77.8 %, 78.2 % and 50.5 % for the X, Y and Z components, respectively. For the most concerned GCC Z component, its correlation with the B1C empirical parameter is reduced from 0.69 to 0.41, demonstrating that the GCC Z component is more separable from the orbital parameters. Besides, the 5th and 7th draconitic harmonics of the Z component are mitigated by 67.0 % and 73.5 %, respectively. The derived annual signal shows a good consistency with the external SLR-based solution, and the amplitude differences are only 0.9 mm, 1.6 mm and 1.2 mm for the X, Y and Z components, respectively. © 2025

关键词： Global positioning system

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Multi-DRFM Jamming Localization Method Using hybrid TDOA-AOA Measurements in Distributed Array Radar 4

Multi-DRFM Jamming Localization Method Using hybrid TDOA-AOA...

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4th International Computational Imaging Conference, CITA 2024

作者： He, Pufeng Tian, Dezhi Li, Renjie Pu, Weiming Liang, Zhennan Liu, Quanhua Radar Technology Research Institute Beijing Institute of Technology Beijing100081 China Key Laboratory of Electronic and Information Technology in Satellite Navigation Beijing Institute of Technology Ministry of Education Beijing100081 China Chongqing Innovation Center Beijing Institute of Technology Chongqing401135 China

ISBN: (纸本)9781510688834

This paper focuses on locating passively multiple digital radio frequency memory (DRFM) jammers in the three-dimensional (3D) space, using hybrid measurements of time difference of arrival (TDOA) and angle of arrival (AOA) observed by a distributed array radar. The method mainly comprises two steps: the grouping of multiple DRFM jamming signals and the jamming localization. Initially, jamming feature sets are generated by extracting amplitude distribution features from the received echoes. Next, leveraging within-cluster compactness and between-cluster separation of different DRFM jamming in the feature sets, we introduce an improved K-means clustering algorithm termed Davies-Bouldin index-based K-means (DBI-K-means). This algorithm integrates the Davies-Bouldin index into the traditional K-means clustering algorithm to improve cluster formation without prior information, enabling accurate estimation of the number of jammers and signal grouping. Furthermore, we propose a closed-form solution method based on multi-station TDOA and single-station AOA measurements. Numerical simulations validate the effectiveness of the proposed method and investigate the impact of AOA measurement errors on its performance. © 2025 SPIE.

关键词： Time difference of arrival

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Two efficient beamforming methods for hybrid IRS-aided AF relay wireless networks

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Science China(information Sciences) 2025年第4期68卷 363-379页

作者： Xuehui WANG Qingbo LI Wen ZHU Feng SHU Mengxing HUANG Fuhui ZHOU Riqing CHEN Cunhua PAN Yongpeng WU Jiangzhou WANG School of Mathematics and Statistics Hainan Normal University Key Laboratory of Data Science and Smart Education Ministry of Education Hainan Normal University School of Information and Communication Engineering Hainan University Collaborative Innovation Center of Information Technology Hainan University School of Electronic and Optical Engineering Nanjing University of Science and Technology College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Digital Fujian Institute of Big Data for Agriculture Fujian Agriculture and Forestry University National Mobile Communications Research Laboratory Southeast University Shanghai Key Laboratory of Navigation and Location Based Services Shanghai Jiao Tong University School of Engineering University of Kent

Owing to its ability to mitigate the double-fading effect by amplifying the reflected signal, the active intelligent reflecting surface(IRS) has garnered significant attention. In this paper, an amplify-and-forward(AF) relay network assisted by a hybrid IRS consisting of both passive and active units is developed. A signal-to-noise ratio(SNR) maximization problem is formulated, where the AF relay beamforming matrix and the hybrid IRS reflecting coefficient matrices for two-time slots need to be optimized. To address the SNR maximization problem, this paper proposes both a high-performance(HP) method and a low-complexity(LC) method. The HP method is based on the semidefinite relaxation and fractional programming(SDR-FP)algorithm, with rank-1 solutions obtained through Gaussian randomization. For the LC method, the amplification coefficient of each active IRS element is assumed to be equal. The SNR maximization problem is then addressed using the whitening filter,generalized power iteration, and generalized Rayleigh-Ritz(WF-GPI-GRR) approach. Simulation results show that compared with the benchmarks, such as the passive IRS-aided AF relay network, the proposed HP-SDR-FP and WF-GPI-GRR methods achieve significant rate improvements. In particular, the HP-SDR-FP and WF-GPI-GRR methods yield more than a 135.0%rate gain when the transmit power Ps of the source is 10 dBm. Furthermore, the proposed HP-SDR-FP method outperforms the WF-GPI-GRR method in terms of rate performance.

关键词： double-fading intelligent reflecting surface active elements passive elements hybrid IRS AF relay

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Broadband, high-linearity TFLN electro-optic modulator for integrated microwave photonics using reconfigurable dual-parallel modulation

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Optics Express 2025年第6期33卷 13805-13815页

作者： Qin, Yan-Yan Gu, Xiao-Wen Tang, Jie Ye, Hui-Yan Dong, Wen-Hao Song, Yuan-Jun Qian, Guang Zhang, Xiao-Yang Zhang, Tong Southeast University Joint International Research Laboratory of Information Display and Visualization School of Electronic Science and Engineering Jiangsu Nanjing210096 China National Key Laboratory of Solid-state Microwave Devices and Circuits Nanjing210016 China Nanjing Electronic Devices Institute Nanjing210016 China Key Laboratory of Micro-inertial Instrument and Advanced Navigation Technology Ministry of Education School of Instrument Science and Engineering Southeast University Jiangsu Nanjing210096 China Suzhou Key Laboratory of Metal Nano-optoelectronic Technology Southeast University Suzhou Campus Jiangsu Suzhou215123 China

Integrated electro-optic modulators with large bandwidth, high linearity and low driving voltage are key building blocks for integrated microwave photonic (IMWP) links to transmit broadband signals with high fidelity. In this work, thin-film lithium niobate electro-optic modulator consisting of a thermo-optic reconfigurable coupler and dual-parallel Mach-Zehnder modulation scheme is proposed and demonstrated to achieve spurious-free dynamic range of 112.87/107.71 dB·Hz2/3 at 1/10 GHz while keeping large bandwidth (>67 GHz) and low half-wave voltage (2.7 V) simultaneously. The demonstration of this device paves a new route for high-performance electro-optic modulators in future functional IMWP systems. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Fiber optic communications Integrated photonics Lithium niobate Microwave photonics Optical components Silicon modulators

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False alarm suppression for a distributed acoustic sensing system utilizing polarization-time division hybrid multiplexing 4

False alarm suppression for a distributed acoustic sensing s...

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4th International Computational Imaging Conference, CITA 2024

作者： Gu, Jiexuan Zhang, Xueliang Lu, Yang Liu, Pengcheng Wang, Dongying Liang, Rui Meng, Zhou College of Meteorology and Oceanology National University of Defense Technology Changsha410073 China Key Laboratory of Intelligent Monitoring on Navigation Safety School of Electronic Science and Engineering Hunan University of Information Technology Changsha410151 China

ISBN: (纸本)9781510688834

In this article, we propose an approach based on polarization-time division hybrid multiplexing to suppress the false alarm induced by fading noise. The method connects a Faraday rotating mirror (FRM) to the end of the polarization-maintaining (PM) fiber so as to interrogate the two principal axes of the PM in sequence. By leveraging the non-uniform distribution of Rayleigh backscattering (RBS) points along the two principal axes of the PM fiber and the polarization dependence of the RBS intensity, the probability of false alarms is significantly reduced. The experiment uses PM fiber as the sensing fiber, and the effectiveness of the proposed method is experimentally confirmed by reduction of false alarm probability from 10-2 to 10-5 © 2025 SPIE.

关键词： Mirrors

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A Novel GNSS Decentralized Cooperative Positioning Algorithm for Internet of Vehicles

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IEEE Internet of Things Journal 2025年第9期12卷 12792-12802页

作者： Xie, Ting Huang, Fei Li, Fang Yao, Hexiong Ouyang, Mingjun Dai, Zhiqiang Zhu, Xiangwei Lin, Qianqiang Sun Yat-sen University Shenzhen Key Laboratory of Navigation and Communication Integration School of Electronics and Communication Engineering Shenzhen Campus Shenzhen518107 China Shenzhen University School of Architecture and Urban Planning Department of Urban Informatics Shenzhen518060 China Guangdong Polytechnic Normal University School of Electronics and Information Technology Guangzhou510665 China National University of Defense Technology National Key Laboratory of Science and Technology on ATR College of Electronic Science and Technology Changsha410073 China

With cooperative positioning (CP) in Internet of Vehicles (IoV), the positioning performance can be improved by utilizing the positioning information provided by neighboring vehicles. However, in urban canyons, the CP performance based on global navigation satellite system (GNSS) is severely degraded by multipath and non-line-of-sight (NLOS) effects, and a robust CP algorithm is required. This article proposes a GNSS decentralized CP (DCP) algorithm based on the generalized extreme studentized deviate test (GESD) filter. Further, a new two-stage CP framework is established, consisting of two modules, the independent and connected modules. The independent module is the first filter layer detection for GNSS pseudorange residual error, operating independently within each vehicle to mitigate the impact of abnormal measurements, such as multipath bias and satellite faults. When receiving data from neighboring vehicles, the connected module is activated to detect shared GNSS pseudorange errors and relative pseudorange measurements, further reducing the impact of anomalous measurements. The outdoor experiments validate the superiority of the DCP algorithm over the single-point positioning (SPP) method based on receiver autonomous integrity monitoring fault detection and exclusion (RAIM-FDE) in both GPS-only and GPS/BDS combination strategies, especially in blocked situations. The positioning root-mean-square error (RMSE) of the DCP algorithm for horizontal positioning is about 1.00 m in static scenes and about 8.00 m in dynamic scenes. Compared with the SPP-RAIM, the DCP algorithm can improve about 25.22%–43.04% and 16.55%–40.17% on average under GPS/BDS combination strategies in the horizontal and 3-D directions, respectively. © 2014 IEEE.

关键词： Mean square error

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Multipath Ghost Recognition and Suppression Method Based on Template Matching for Indoor Human Detection and Location

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IEEE Internet of Things Journal 2025年

作者： Yang, Xiaopeng Meng, Haoyu Qu, Xiaodong Gao, Weicheng Liu, Feiyang Beijing Institute of Technology School of Information and Electronics Beijing100081 China Ministry of Education Key Laboratory of Electronic and Information Technology in Satellite Navigation Beijing100081 China Beijing Institute of Technology Advanced Technology Research Institute Jinan250300 China

Indoor human detection and location is a prominent research area within the internet of things, which can be effectively realized using radar technology. However, the electromagnetic waves will be reflected by the wall, leading to multipath ghosts in radar image, resulting in increased false alarm rates and degraded target location accuracy. In order to address this challenge, a multipath ghost recognition and suppression method based on template matching is proposed in this paper. It is proved that the shape can be modeled as ellipse and the major axis and rotation angle of ghost is different from that of target. Two distinct features are calculated and used to achieve ghost recognition, and ghost mask is generated further. The effectiveness and robustness of the proposed method are validated through simulations and experimental results. Particularly, the proposed method does not depend on the information of building layout and is geometry-layout-free. © 2014 IEEE.

关键词： Radar imaging

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