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Low complexity robust adaptive beamforming for general-rank signal model with positive semidefinite constraint

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Frontiers of Information Technology & Electronic Engineering 2016年第11期17卷 1245-1252页

作者： Yu-tang ZHU Yong-bo ZHAO Jun LIU Peng-lang SHUI national laboratory of radar signal processing Xidian University

We propose a low complexity robust beamforming method for the general-rank signal model, to combat against mismatches of the desired signal array response and the received signal covariance matrix. The proposed beamformer not only considers the norm bounded uncertainties in the desired and received signal covariance matrices, but also includes an additional positive semidefinite constraint on the desired signal covariance matrix. Based on the worst-case performance optimization criterion, a computationally simple closed-form weight vector is obtained. Simulation results verify the validity and robustness of the proposed beamforming method.

关键词： Beamforming General-rank Low complexity Positive semidefinite(PSD) constraint Model mismatches

IMM Robust Cardinality Balance Multi-Bernoulli Filter for Multiple Maneuvering Target Tracking with Interval Measurement

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Chinese Journal of Electronics 2021年第6期30卷 1141-1151页

作者： YANG Biao ZHU Shengqi HE Xiongpeng national laboratory of radar signal processing Xidian University

This paper presents a novel Interacting multi-model(IMM) Robust Cardinality balance multitarget multi-Bernoulli(R-CBMe MBer) filter to solve the maneuvering target tracking problem in the case of interval measurement, unknown detection probability and unknown clutter density. In essence, IMM R-CBMe MBer filter is an extended application of R-CBMe MBer *** the IMM R-CBMe MBer filter, the target state is first extended to distinguish clutter from the real *** detection probability and model probability of the target can be adaptively updated. Then, generalized likelihood function and IMM algorithm are introduced to interactively predict and update the state of the target in the IMM R-CBMe MBer filtering process. In addition,a particle application of the IMM R-CBMe MBer filter is given, and a numerical experiment is designed under nonlinear conditions. Meanwhile, Doppler information of the target is employed to estimate the velocity of each maneuvering target. Numerical experiments also verify that the IMM R-CBMe MBer filter can effectively estimate the target position, target velocity, target detection probability and clutter number in the condition of unknown detection probability, unknown clutter rate and interval measurement.

关键词： Optical, image and video signal processing Filtering methods in signal processing Computer vision and image processing techniques Other topics in statistics Other topics in statistics Multiple maneuvering target tracking Random finite set Interacting multiple model Cardinality balance multiple targets multi-Bernoulli filter Generalized likelihood function

Property analysis of bistatic forward-looking SAR with arbitrary geometry

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Journal of Systems Engineering and Electronics 2016年第1期27卷 111-127页

作者： Ziqiang Meng Yachao Li Mengdao Xing Zheng Bao national laboratory of radar signal processing Xidian University

Bistatic forward-looking synthetic aperture radar（SAR） has many advantages and applications owing to its twodimensional imaging *** could be various imaging configurations because of the geometric flexibility of bistatic platforms,resulting in kinds of models built independently among which there could be some similar even the same motion *** research on such systems in a more comprehensive and general point of view is required to address their difference and *** analysis of bistatic forwardlooking SAR with arbitrary geometry is achieved including stripmap and spotlight modes on airborne platform,missile-borne platform,and hybrid platform of *** is placed on azimuth space variance of some key parameters significantly affecting the subsequent imaging processing,based on which the frequency spectra are further described and compared considering respective features of different platforms for frequency imaging algorithm *** results confirm the effectiveness and correctness of our analysis.

关键词： bistatic forward-looking synthetic aperture radar(SAR) comprehensive research property analysis azimuth space variance.

Fast Transmit Beamforming for Large Planar MIMO radar

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Chinese Journal of Electronics 2020年第4期29卷 759-765页

作者： LIU Bingfan CHEN Baixiao national laboratory of radar signal processing Xidian University

A fast method of transmit beamforming for large planar Multiple-input multiple-output(MIMO)radar is *** MIMO radar with large elements,it is difficult to design a large number of orthogonal *** design a weight matrix to connect orthogonal waveforms and array *** optimize the weight matrix such that the transmit beampattern approximates the desired transmit *** introducing an auxiliary variable, a cyclic optimization algorithm based on Fast fourier transform(FFT) is proposed to obtain the optimal weight matrix, which is very efficient and can satisfy the real-time *** examples are provided to verify the effectiveness of the proposed algorithm.

关键词： MIMO radar Transmit beamforming Planar array

Multi-dimensional ambiguity function for subarray-based space-time coding radar

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Journal of Systems Engineering and Electronics 2019年第5期30卷 886-896页

作者： LAN Lan LIAO Guisheng XU Jingwei WANG Hanbing national laboratory of radar signal processing Xidian University

Space-time coding radar has been recently proposed and *** is a radar framework which can perform transmit beamforming at the ***,the range resolution decreases when the number of the transmit element increases.A subarray-based space-time coding(sub-STC)radar is explored to alleviate the range resolution *** the proposed radar configuration,an identical waveform is transmitted and it introduces a small time offset in different *** multidimensional ambiguity function of sub-STC radar is defined by considering resolutions in multiple domains including the range,Doppler,angle and probing *** on properties of the multi-dimensional ambiguity function of the sub-STC radar with regard to the spatial coverage,resolution performance and low sidelobes are also *** reveal that the range resolution and low sidelobes performance are improved with the proposed approach.

关键词： space-time coding radar multi-dimensional ambiguity function range resolution wide spatial coverage subarray sidelobe

Target detection for low angle radar based on multi-frequency order-statistics

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Journal of Systems Engineering and Electronics 2015年第2期26卷 267-273页

作者： Yunhe Cao Shenghua Wang Yu Wang Shenghua Zhou national laboratory of radar signal processing Xidian University

For radar targets flying at low altitude, multiple pathways produce fade or enhancement relative to the level that would be expected in a free-space environment. In this paper, a new detec- tion method based on a wide-ranging multi-frequency radar for low angle targets is proposed. Sequential transmitting multiple pulses with different frequencies are first applied to decorrelate the cohe- rence of the direct and reflected echoes. After receiving all echoes, the multi-frequency samples are arranged in a sort descending ac- cording to the amplitude. Some high amplitude echoes in the same range cell are accumulated to improve the signal-to-noise ratio and the optimal number of high amplitude echoes is analyzed and given by experiments. Finally, simulation results are presented to verify the effectiveness of the method.

关键词： multipath signal detection order statistic multi-frequency low angle

Multidimensional Waveform Design for MIMO SAR Interferometry

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Chinese Journal of Electronics 2018年第1期27卷 198-205页

作者： LIU Nan ZHANG Linrang national Key laboratory of radar signal processing Xidian University

One key of Multiple-input multiple-output(MIMO) Synthetic aperture radar(SAR) interferometry is the effective separation of the echoes originating from different transmissions. A multidimensional waveform design method for MIMO SAR interferometry is presented. By exploiting the wavenumber shift and Doppler-band shift phenomenon in the design of transmitted signals, the echo separation can be efficiently accomplished via the filtering operations in range-frequency domain and azimuth-spatial domain. Such waveform design can meet the requirement of MIMO SAR imaging on integrated cross interference level without reduce the swath width. Such waveform design also improves the coherence between the independent observations and enlarges the unambiguity range of height estimation. The results of the numerical simulations demonstrate the feasibility of the proposed waveform design method.

关键词： Synthetic aperture radar(SAR) interferometry Multiple-input multiple-output(MIMO) Multidimensional waveform design Echo separation

VCR-LFM-BPSK signal design for countering advanced interception technologies

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Journal of Systems Engineering and Electronics 2021年第2期32卷 380-388页

作者： WANG Shanshan LIU Zheng XIE Rong WANG Jingjing national laboratory of radar signal processing Xidian UniversityXi’an 710071China

The hybrid waveform of linear frequency modulation and binary phase shift keying(LFM-BPSK)can take advantages of the LFM and BPSK signals,and reduce the defects of ***,with the development of interception technology for the LFM-BPSK signal,the application of the signal is *** this paper,to improve the anti-interception performance of the hybrid waveform,a new waveform of LFM-BPSK with the varying chirp rate(denoted as VCR-LFM-BPSK)is *** this design,based on the working principle of the interception frame for the LFM-BPSK signal,different chirp rates are introduced in different sub-pulses to prevent the signal from being intercepted by the ***,to further improve the anti-interception performance of the VCR-LFM-BPSK signal,the chirp rates are optimized by minimizing the interception capability of the ***,based on the VCR-LFM-BPSK signal with the optimized chirp rates,the binary phases are designed via a multiobjective Pareto optimization to improve the capabilities of autocorrelation and *** results demonstrate that the designed VCR-LFM-BPSK signal outperforms the traditional LFM-BPSK signal in countering the advanced interception technologies.

关键词： hybrid waveform waveform design anti-interception optimization

Short-range clutter suppression method combining oblique projection and interpolation in airborne CFA radar

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Journal of Systems Engineering and Electronics 2021年第1期32卷 92-102页

作者： HU Yili ZHAO Yongbo PANG Xiaojiao CHEN Sheng national laboratory of radar signal processing Xidian UniversityXi’an 710071China

The airborne conformal array(CFA)radar's clutter ridges are range-modulated,which result in a bias in the estimation of the clutter covariance matrix(CCM)of the cell under test(CUT),further,reducing the clutter suppression performance of the airborne CFA *** clutter ridges can be effectively compensated by the space-time separation interpolation(STSINT)method,which costs less computation than the space-time interpolation(STINT)method,but the performance of interpolation algorithms is seriously affected by the short-range clutter,especially near the platform *** distributions of CFA are free,which yields serious impact that range spaces of steering vector matrices are non-orthogonal complement and even no longer ***,a new method is proposed that the shortrange clutter is pre-processed by oblique projection with the intersected range spaces(OPIRS),and then clutter data after being pre-processed are compensated to the desired range bin through the STSINT *** OPIRS also has good compatibility and can be used in combination with many existing *** the same time,oblique projectors of OPIRS can be obtained in advance,so the proposed method has almost the same computational load as the traditional compensation *** addition,the proposed method can perform well when the channel error *** simulation results verify the effectiveness of the proposed method.

关键词： airborne conformal arrays(CFA)radar oblique projection intersected range space short-range clutter suppression