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Interference mitigation and target detection for automotive FMCW radar with range-Doppler sparse regularization

Science China(Information Sciences) 2024年第9期67卷 342-343页

作者： Yan HUANG Yunxuan WANG Xiao ZHOU Hui ZHANG Yuan MAO Guisheng LIAO Wei HONG State Key Lab of Millimeter Waves Southeast University Department of Computer Science University College London National Key Lab of Radar Signal Processing Xidian University

The invention of vehicles has shaped our modern society and accelerated our economy while causing many tragic incidents simultaneously. Some advanced driver-assistance systems(ADAS) based on surrounding environment se... 详细信息

关键词： radar interference

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Deceptiv e Jamming against SAR via Range-Azimuth Two-Dimensional Modulation

Deceptiv e Jamming against SAR via Range-Azimuth Two-Dimensi...

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2024 IEEE International Workshop on Technologies for Defense and Security, TechDefense 2024

作者： Liu, Yangyang Lan, Lan Liao, Guisheng Xu, Jingwei Xidian University National Key Lab of Radar Signal Processing Xi'an China

ISBN: (纸本)9798331505585

This paper aims to achieve deceptive jamming against Synthetic aperture radar (SAR), which is of significance in electronic warfare. At the modeling stage, a SAR deceptive jamming scheme is developed by introducing range-azimuth twodimensional modulation to generate multiple false targets. In addition, an active cancellation is employed to eliminate the true target. In this context, the range and azimuth positions of false targets can be accurately manipulated through the design of corresponding modulation terms. Moreover, the number of false targets can be determined by setting transmit elements. Finally, after applying the range-Doppler (RD) algorithm with the victim SAR, the high-resolution imaging with multiple false targets can be obtained. Simulation results demonstrate the feasibility and effectiveness of the proposed scheme for SAR jamming in terms of different system parameters. © 2024 IEEE.

关键词： Synthetic aperture radar

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Complex-Valued SAR Image Super-Resolution via Subaperture Learning and Fusion

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2025年 63卷

作者： Dong, Ganggang Wang, Yao Liu, Hongwei Liu, Songlin Xidian Univ State Key Lab Radar Signal Proc Shaanxi 710071 Peoples R China State Key Lab Smart Earth Beijing 100029 Peoples R China

Synthetic aperture radar (SAR) imaging is a popular tool in many fields, while the contradiction between resolution and coverage is an open problem. The range resolution relies on the bandwidth of transmitted signals, while the azimuth resolution is dependent on the length of the synthesized aperture. They are related to radar configurations and are infeasible to be tuned freely. To solve the problem, a new SAR image super-resolution method is proposed in this article. It is composed of preimaging, feature learning, and reconstruction. In the first phase, the zero-padded technique is used to achieve spatial alignment. The result is then decomposed along the subapertures, forming the subaperture images and the subband images. They were delivered to the second phase for cross-domain learning and hierarchical fusion. The prelearning, encoder-decoder, and refinement are configured. The learned features are finally tuned for super-resolution reconstruction. On this basis, a new evaluation system was built to measure the performance. Both the supervised evaluation and the unsupervised evaluation are considered. An improvement of 3.78% is achieved for the amplitude components, while the phase accuracy is 4.62% better than the competitor.

关键词： Superresolution Image resolution radar imaging radar polarimetry Imaging signal resolution Image reconstruction Bandwidth radar Deconvolution Deep learning quality assessment radar imaging super-resolution synthetic aperture radar (SAR)

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Long-time Coherent Accumulation Algorithm for Variable Acceleration Maneuvering Targets Based on TRT 2

Long-time Coherent Accumulation Algorithm for Variable Accel...

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

作者： Zhang, Shu Li, Ming Xu, Dazhi National Key Lab for Radar Signal Processing Xidian University Xi'an710071 China

ISBN: (纸本)9781510663121

Aiming at the high-order range walk and Doppler walk problems encountered by maneuvering targets in the long-time coherent accumulation process, a long-time coherent accumulation algorithm for variable acceleration maneuvering targets based on time reversing transform (TRT) is proposed. Firstly, the time series inversion transformation is performed on the echo signal after de-carrier frequency and pulse compression, which can correct the linear distance walking caused by the maneuvering target speed and the high-order distance walking and Doppler walking caused by the variable acceleration. Multi-linear function transformation is used to correct the second-order range walk and linear Doppler walk caused by acceleration, finally, FFT and IFFT are used to achieve coherent accumulation of target energy. Simulation experiments show that the proposed algorithm is effective in correcting the moving objects with variable acceleration. At the same time, the detection performance of the algorithm is better than that of the PHAF algorithm, the RFT algorithm, the RFRFT algorithm and the RFRAF algorithm. It has lower computational complexity and does not require search for motion parameters. © 2023 SPIE.

关键词： Acceleration

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One-Bit Synthetic Aperture radar Imaging Based on Fixed-Threshold With Slow-Time Fluctuations

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2025年 63卷

作者： Nie, Guoli Zhao, Bo Liu, Qiuchen Huang, Lei Liao, Guisheng Shenzhen Univ State Key Lab Radio Frequency Heterogeneous Integr Shenzhen 518060 Peoples R China Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China

Due to the limited resources available on small synthetic aperture radar (SAR) platforms, such as unmanned aerial vehicles (UAVs), one-bit SAR imaging has emerged as a promising technique, particularly with the rapid development of low-altitude economy. One-bit SAR is capable of leveraging a very simple and cheap one-bit analog-to-digital converter (ADC) to complete the same sensing task as those in the conventional SAR using high-resolution ADC. Nevertheless, the one-bit quantization incurs some intractable problems, such as signal amplitude distortion and the emergence of unwanted interference, which seriously degrade the SAR image quality. To tackle these problems, this work proposes a one-bit SAR imaging strategy that devises a quantization threshold fixed in fast-time but fluctuating in slow-time. Specifically, within the one-bit quantization procedure for each echo pulse, the threshold is fixed, significantly simplifying the SAR system. On the other hand, the slow-time fluctuation of the threshold enables the SAR to reassign spectrum energies, effectively suppressing unwanted interference. The frequency of the threshold and the corresponding pulse repetition frequency (PRF) of the SAR system are elaborately designed. In addition, the fluctuation range of the threshold, which determines the fidelity of SAR images directly, is designed as well, and a closed-form expression for the threshold fluctuation range is determined. The effectiveness of the proposed scheme is demonstrated through the simulated and real-data experiments, confirming that high-quality one-bit SAR images can be achieved.

关键词： One-bit quantization slow-time fluctuated threshold synthetic aperture radar (SAR) One-bit quantization slow-time fluctuated threshold synthetic aperture radar (SAR)

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Performance Analysis and Secure Resource Allocation for Relay-Aided MISO-NOMA Systems

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IEEE SYSTEMS JOURNAL 2024年第3期18卷 1617-1628页

作者： Li, Huifang Li, Jing Liu, Meng Gong, Fengkui Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Peoples R China Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China

In this article, we investigate the physical layer security for a relay-aided multiple-input single-output (MISO) nonorthogonal multiple access (NOMA) system, where an eavesdropper tries to intercept confidential information transmission from the source and the relay by employing selection combining and maximal ratio combining, respectively. Specifically, we propose an optimal transmit antenna selection scheme to exploit the inherent spatial diversity gain for security enhancement. The closed-form expressions for the secrecy outage probability are derived to facilitate the system performance evaluation. At a more pragmatic level, we consider multiple users in the relay-aided MISO NOMA system and thus propose a user pairing algorithm to perfect successive interference cancellation. The algorithm avoids full search over all users by exploiting two-sided matching and low-complexity greed, thereby reducing the total complexity. Furthermore, aiming to maximize the secrecy rate, we formulate an optimization problem. Hence, the power allocation schemes are developed by jointly considering power limits and rate requirements. The scheme achieves closed-form solutions of power allocation for the data rate requirements of each user. Finally, simulation results validate the accuracy of the derived analysis and the improvement significant in secrecy performance by the proposed algorithm and scheme.

关键词： Cooperative relaying nonorthogonal multiple access (NOMA) resource allocation secure transmission Cooperative relaying nonorthogonal multiple access (NOMA) resource allocation secure transmission

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Robust beamforming method based on FDA-MIMO radar

Robust beamforming method based on FDA-MIMO radar

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IET International radar Conference 2023, IRC 2023

作者： Wu, Zhixia Zhu, Shengqi Xu, Jingwei Lan, Lan Li, Ximin Liu, Feilong Wang, Yike Kan, Qingyun National Key Lab. of Radar Signal Processing Xidian University Xi'an710071 China

ISBN: (纸本)9781839539954

In this work, a robust two-dimensional beamforming algorithm based on frequency diversity array multiple-input multiple-output (FDA-MIMO) radar is proposed. The algorithm focuses on scenarios where mainlobe deceptive jamming and sidelobe barrage jamming coexist, taking into account estimation errors in the jamming angle-range. The algorithm initially employs a smoothing technique to eliminate true targets from the samples, utilizing the Mailloux method to expand the null associated with jamming, thereby ensuring robustness against errors. Simulation results confirm the effectiveness of the proposed algorithm. © The Institution of Engineering & Technology 2023.

关键词： MIMO radar

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A multi-frame track-before-detect algorithm based on root label clustering for multiple targets

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Chinese Journal of Aeronautics 2022年第5期35卷 87-96页

作者： Jiaqi ZHANG Haihong TAO Xiushe ZHANG Chunlei HAN State Key laboratory of Radar Signal Processing Xidian UniversityXi’an 710068China Xi’an Research Institute of Navigation Technology Xi’an 710071China

In this paper,a novel multi-frame track-before-detect algorithm is proposed,which is based on root label clustering to reduce the high computational complexity arising by observation area expansion and clutter/noise density increase.A criterion of track extrapolation is used to construct state transition set,root label is marked by state transition set to obtain the distribution information of multiple targets in measurement space,then measurement plots of multi-frame are divided into several clusters,and finally multi-frame track-before-detect algorithm is implemented in each *** computational complexity can be reduced by employing the proposed *** results show that the proposed algorithm can accurately detect multiple targets in close proximity and reduce the number of false tracks.

关键词： Multi-frame track-before-detect Multiple targets detection Root label clustering state transition set Track extrapolation

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HICEScore: A Hierarchical Metric for Image Captioning Evaluation 24

HICEScore: A Hierarchical Metric for Image Captioning Evalua...

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32nd ACM International Conference on Multimedia, MM 2024

作者： Zeng, Zequn Sun, Jianqiao Zhang, Hao Wen, Tiansheng Su, Yudi Xie, Yan Wang, Zhengjue Chen, Bo National Key Laboratory of Radar Signal Processing Xidian University Xi'an China State Key Laboratory of Integrated Service Networks Xidian University Xi'an China

ISBN: (纸本)9798400706868

Image captioning evaluation metrics can be divided into two categories, reference-based metrics and reference-free metrics. However, reference-based approaches may struggle to evaluate descriptive captions with abundant visual details produced by advanced multimodal large language models, due to their heavy reliance on limited human-annotated references. In contrast, previous reference-free metrics have been proven effective via CLIP cross-modality similarity. Nonetheless, CLIP-based metrics, constrained by their solution of global image-text compatibility, often have a deficiency in detecting local textual hallucinations and are insensitive to small visual objects. Besides, their single-scale designs are unable to provide an interpretable evaluation process such as pinpointing the position of caption mistakes and identifying visual regions that have not been described. To move forward, we propose a novel reference-free metric for image captioning evaluation, dubbed Hierarchical Image Captioning Evaluation Score (HICE-S). By detecting local visual regions and textual phrases, HICE-S builds an interpretable hierarchical scoring mechanism, breaking through the barriers of the single-scale structure of existing reference-free metrics. Comprehensive experiments indicate that our proposed metric achieves the SOTA performance on several benchmarks, outperforming existing reference-free metrics like CLIP-S and PAC-S, and reference-based metrics like METEOR and CIDEr. Moreover, several case studies reveal that the assessment process of HICE-S on detailed captions closely resembles interpretable human judgments. Our code is available at https://***/joeyz0z/HICE. © 2024 ACM.

关键词： Visual languages

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An Unambiguous Angle and Range Estimation Method using MR-FDA-MIMO radar 2

An Unambiguous Angle and Range Estimation Method using MR-FD...

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2nd IEEE International Conference on signal, Information and Data processing, ICSIDP 2024

作者： Wang, Zhengxi Zhu, Shengqi Li, Ximin Lan, Lan Liu, Congfeng Xidian University National Key Lab of Radar Signal Processing Xi'an China Xidian University Key Lab of Electronic Information Countermeasure and Simulation Technology Ministry of Education Xi'an China

ISBN: (纸本)9798331515669

Frequency diversity array (FDA) multiple-input multiple-output (MIMO) radar systems have drawn widespread focus due to their capacity for providing angular and range information simultaneously. Unfortunately, the estimation accuracy is constrained by the amount of physical sensors. This paper proposes a method for unambiguous angle and range estimation using a combination of the minimum redundancy array (MRA) and FDA-MIMO radar. The MRA is applied to extend array degrees of freedom by differential processing. Following the implementation of range compensation, a two-dimensional spatially smoothed algorithm is employed to address the rank deficit issue in the equivalent array. Finally, the target's angle, ambiguous zone and range offset are identified through a MUSIC algorithm. The efficacy for the designed methodology is corroborated by the simulated experimental outcomes. © 2024 IEEE.

关键词： Frequency estimation

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