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Digital Instantaneous Frequency Measurement of a Real Sinusoid Based on Three Sub-Nyquist Sampling Channels

MATHEMATICAL PROBLEMS IN ENGINEERING 2020年第1期2020卷

作者： Su, Yu Jiang, Defu Array and Information Processing Laboratory Hohai University 213022 Nanjing China

Multichannel sub-Nyquist sampling is an efficient technique to break through the limitation of the Nyquist sampling theorem for the wideband digital instantaneous frequency measurement (DIFM) receiver. The significant challenge is calculating the folding frequency and solving the ambiguity quickly and accurately. Usually, the researchers adopt a fast Fourier transform (FFT) to calculate the folding frequency and a Chinese remainder theorem (CRT) to solve the ambiguity caused by undersampling. However, these algorithms have the drawback of long response time. In this paper, we use a frequency deduction algorithm based on the total least-squares estimation to measure the folding frequency accurately within a few clocks. We propose a frequency-band division algorithm by dividing the measurable frequency range into a few sub-bands to solve the frequency ambiguity. This deblurring algorithm is more efficient and faster than CRT. We analyse the performance of our algorithms by numerical simulations and functional hardware simulations and compare them with FFT and CRT. We also conduct experiments on a hardware platform to confirm the effectiveness of our algorithms. The simulation results show that our algorithms have better performance than FFT and CRT in accuracy and response time. Board-level measurement results verify that the proposed DIFM technique can capture the frequency from 0 to 5,000 MHz with a maximum of 0.8 MHz root-mean-squared error in less than 200 ns.

关键词： Fast Fourier transforms

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Fractionally Nyquist Sample Spaced ARMA Blind Equalizer for Direct Signal Recovery in Passive Bistatic Radar

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Chinese Journal of Electronics 2017年第3期27卷 658-666页

作者： WANG Feng SHEN Wei JIANG Defu WEI Shuang Array and Information Processing Laboratory College of Computer and Information Hohai University Nanjing Research Institute of Electronics Technology

This paper proposes a modified signal processing structure based on the fractionally Nyquist sample spaced structure for passive bistatic *** recover the direct signal from the multipath clutter,an equalizer of the Auto regressive moving average(ARMA)type is proposed based on the fractionally Nyquist sample spaced constant modulus *** with the conventional Nyquist sample spaced equalizer,the equalizer of the fractionally Nyquist sample spaced ARMA structure is more effective in dealing with deep fading multipath channels with zeros near the unit *** simulations and real data tests indicate that the proposed approach outperforms the conventional processing structure in terms of both clutter residual and mean square error.

关键词： Passive bistatic radar Constant modulus algorithm Direct signal recovery Multipath clutter cancellation Fractionally spaced equalizer

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Charging Out Rectangle: Quadrangle IoU for Scene Text Detection under Balanced Supervision 25

Charging Out Rectangle: Quadrangle IoU for Scene Text Detect...

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Proceedings of the 4th International Conference on Computer, Artificial Intelligence and Control Engineering

作者： Min Ma Xiangnan Zhang Wang Bin Qiuli Wang Kexing Che School of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing Jiangsu China Key Laboratory of Intelligent Information Processing Corporation Key Laboratory of Aperture Array and Space Application The 38th Research Institute of China Electronics Technology Group Hefei Anhui China Government and Enterprise Division China Unicom Shandong Branch Jinan Shandong China School of Electronic Engineering Xidian University Xi' an Shaanxi China

ISBN: (纸本)9798400712647

In the past few years, text detection approaches have been able to cope with more and more challenging complex scenes. In this field, the arbitrary shape and various scale of text instances are the two most frequently mentioned topics. Among the existing methods, the bounding box prediction methods based on Intersection over Union (IoU) are efficient, but can only handle multi-oriented rectangles. Although arbitrary shape text detection methods have been proposed, these methods are often aimed at curved text. Besides, the post-processing is usually cumbersome. Considering that the affine transformation phenomenon caused by out-plane rotation is more frequent than curved text in real scenario, we design a quadrangle IoU (QIoU) loss to efficiently predict arbitrary convex quadrangle text. Furthermore, we analyze the challenge of variable scale in text detection from the perspective of unbalanced supervision information, and propose a cross-scale knowledge distillation (CSKD) method to improve the detection accuracy of large-scale text. An extensive ablation study demonstrates the effectiveness and superiority of the proposed strategies. During inferring, our method does not consume extra time. Using the basic feature pyramid network for feature extraction, our method achieves state-of-the-art results on several popular datasets for scene text detection.

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Direction of arrival estimation using sum co-array of coprime arrays

Direction of arrival estimation using sum co-array of coprim...

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2017 International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2017

作者： Li, Jianfeng Wang, Feng Jiang, Defu Array and Information Processing Laboratory College of Computer and Information Hohai University Nanjing211100 China

ISBN: (纸本)9780996007856

In this paper, direction of arrival (DOA) estimation using sum co-array of coprime arrays is studied. The array geometry can be represented as the kronecker product of those of two coprime arrays. This array structure can reduce the aperture loss when extracting the subarrays, which are jointly used to achieve high resolution and unique DOA estimation via low computational propagator method. Compare to original coprime arrays based method, the proposed algorithm achieves better estimation results. Besides, the proposed method has low complexity for it requires neither peak search nor eigenvalue-decomposition. Simulation results verify the effectiveness of the proposed approach. © 2017 Applied Computational Electromagnetics Society.

关键词： Eigenvalues and eigenfunctions

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Direction of arrival estimation using sum co-array of coprime arrays

Direction of arrival estimation using sum co-array of coprim...

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International Applied Computational Electromagnetics Society Symposium in China

作者： Jianfeng Li Feng Wang Defu Jiang Array and information processing laboratory College of computer and information Hohai University

ISBN: (纸本)9781509043118

关键词： Direction-of-arrival estimation Estimation Antenna arrays Apertures array signal processing Simulation

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Variational Bayesian adaptation of noise covariances in Trajectory PHD Filter 2

Variational Bayesian adaptation of noise covariances in Traj...

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2nd International Conference on Electronic information Engineering and Computer Communication, EIECC 2022

作者： Han, Zhixian Jiang, Biying Lu, Xingchen Laboratory of Array and Information Processing College of Computer and Information Hohai University Nanjing210098 China The 28th Research Institute of China Electronics Technology Group Corporation Nanjing210007 China

ISBN: (纸本)9781510663121

The trajectory probability hypothesis density (TPHD) filter is a promising multi-target tracking algorithm. However, in many practical applications, inaccurate measurement noise prior statistics can degrade the performance of TPHD filters. In this paper, we model the trajectory state in TPHD as the product of the Gaussian mixture with the inverse Wishart under the linear Gaussian model, and propose the IW-VB-TPHD filter to adaptively acquire the covariance of measurement noise. Compared with the IG-VB-TPHD filter, simulation results show that the IW-VB-TPHD filter has a better accuracy in target tracking. © 2023 SPIE.

关键词： Trajectories

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Multi-targets detection using 3D-FFT scheme for TDM-MIMO automotive radar 2

Multi-targets detection using 3D-FFT scheme for TDM-MIMO aut...

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2nd International Conference on Electronic information Engineering and Computer Communication, EIECC 2022

作者： Tian, Chenyong Jiang, BiYing Yang, Zequn Laboratory of Array and Information Processing College of Computer and Information Hohai University Nanjing210100 China The 28th Research Institute of China Electronics Technology Group Corporation Nanjing210007 China

ISBN: (纸本)9781510663121

Automotive radar is the key component of driver assistance system. The main current requirements of are high angular resolution, high target detection accuracy, low power consumption, and low cost. However, ambiguous target and low angle measurement accuracy will appear in the multi-target scenario. In order to solve these problems, TDM-MIMO (time division multiplexing multiple-input-multiple-output) radar is implemented to improve the angular resolution. We use the proposed TDM-MIMO LFMCW (linear frequency modulated continuous wave) echo model to derive the range, velocity and azimuth information of the target. And we present a 3D-FFT (three-dimensional fast Fourier transform) scheme to solve the problem of multi-target detection. In the simulation, we effectively solve the accuracy problem in multi-target detection without ambiguity, and the angular resolution is improved by about 14°. © 2023 SPIE.

关键词： Fast Fourier transforms

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Robust adaptive beamforming based on covariance matrix reconstruction and SV estimation 2

Robust adaptive beamforming based on covariance matrix recon...

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2nd International Conference on Electronic information Engineering and Computer Communication, EIECC 2022

作者： Yang, Zequn Jiang, Biying Laboratory of Array and Information Processing College of Computer and Information Hohai University Nanjing210098 China The 28th Research Institute of China Electronics Technology Group Corporation Nanjing210007 China

ISBN: (纸本)9781510663121

In this research, we propose an optimized robust Capon beamforming (RCB) algorithm, which is based on covariance matrix reconstruction along with steering vector (SV) estimation. It is crucial to assurance the robustness of the beamforming algorithm performs better. The proposed algorithm indicates an alternative method to roughly estimate the SV of the interference signal, thus we are able to construct the optimal Capon space spectrum. Secondly, the reconstructed interference signal covariance matrix is obtained by integrating the optimized Capon space power spectrum in the corresponding sector of the interference signal. Subsequently, we adopt the eigen decomposition of the sample covariance matrix (SCM)to obtain the noise covariance matrix, as well as complete the reconstruction of the interference-plus-noise covariance matrix (IPNCM). Finally, this paper optimizes the algorithm of uncertainty set constraint, as well as gets more accurate desired signal SV. The numerical simulation results obtained through two hundred Monte-Carlo experiments suggest that the proposed algorithm indicates higher robustness, better noise suppression ability, and higher output SINR, which is closer to the optimal output curve than several traditional RAB algorithms. © 2023 SPIE.

关键词： Covariance matrix

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Fast Direction of Arrival Estimation Using a Sensor-Saving Coprime array with Enlarged Inter-Element Spacing

Fast Direction of Arrival Estimation Using a Sensor-Saving C...

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Sensor array and Multichannel Signal processing Workshop

作者： Jianfeng Li Mingwei Shen Defu Jiang Array and information processing laboratory College of computer and information Hohai University Nanjing China

Direction of arrival (DOA) estimation using coprime array is discussed, and a fast method using a sensor-saving coprime array with enlarged inter-element spacing is proposed. Original coprime array combines the results obtained from two coprime subarrays to uniquely determine the DOA estimation, and it is shown in this paper that one subarray actually only requires half of its original sensor number and can achieve enlarged inter-element spacing based on the array compensation from the cross correlation matrix. Thereafter, a fast DOA estimation method, which extracts the noise subspace without eigenvalue decomposition, is proposed to obtain coprime DOA estimations based on one dimensional root finding technique. Final unique DOA is estimated from the coincide results of the coprime estimations. Simulation results verify that the proposed method can achieve almost the same estimation performance as conventional methods while requiring less sensors.

关键词： Estimation Direction-of-arrival estimation Sensor arrays array signal processing Correlation Multiple signal classification

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Dimension degradation of fractionally spaced super-exponential algorithm for sparse channel equalisation

Dimension degradation of fractionally spaced super-exponenti...

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IET International Radar Conference 2018, IRC 2018

作者： Bai, JinLiang Jiang, ZhiYe Wang, Feng Zhou, Yi Sun, Heng National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China Array and Information Processing Laboratory College of Computer and Information Hohai University West Focheng Road No. 8 Jiangning District Nanjing China

Fractionally spaced super-exponential (FSSE) algorithm has the disadvantage of computational complexity since it exploits high-order statistics explicitly. The authors propose a dimension degradation technique for FSSE when it is applied to the equalisation of a sparse channel in accordance with the relationship between the coefficients of the cross fourth-order cumulant (CFOC) in FSSE and the channel impulse response. They implement partial updating on the prominent coefficients of the CFOC with all the small coefficients remaining unchanged. The computational complexity of the modified FSSE reduces significantly with an acceptable performance loss, and its performance is validated via numerical simulations. © This is an open access article published by the IET under the Creative Commons Attribution License (http://***/licenses/by/3.0/)

关键词： Computational complexity

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