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23 results on '"Chang, Shaoqiang"'

6. Coherent Accumulation for Measuring Maneuvering Weak Targets Based on Stepped Dechirp Generalized Radon–Fourier Transform.

Author

Sun, Yuxian, Chang, Shaoqiang, Cai, Bowen, Wang, Dewu, and Liu, Quanhua

Subjects
*FOOD preservation, *LINEAR systems, *PARAMETRIC downconversion, *RADAR, *DATA analysis
Abstract

The problem of accurately measuring the motion parameters of low radar cross-section (RCS) maneuvering targets has long been a hurdle in the radar technology landscape. Small targets, due to their elusive characteristics, are particularly difficult to detect with conventional radar systems. In this paper, we investigate the capabilities of dechirp-receiving stepped-frequency radar, a modern system using a linear frequency modulation signal for downconversion. This permits the radar to function at reduced sampling rates while maintaining the transmission of large-bandwidth signals and achieving synthetic imaging. Our primary contribution is introducing the stepped dechirp generalized Radon–Fourier transform (stepped DGRFT) algorithm. This novel approach allows the radar system to perform coherent accumulation, enhancing the accuracy of motion parameter estimates for low-RCS maneuvering targets. Results from our simulations and measured data analysis validate the effectiveness of our proposed algorithm, demonstrating its superiority over other methods. [ABSTRACT FROM AUTHOR]

Published
2023
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7. Adaptive Main-Lobe Jamming Suppression Based on Cascaded LMS Filter With Low-Cost Distributed Radar

Author

Wang, Changjie, Zheng, Ziming, Zhang, Kaixiang, Chang, Shaoqiang, and Liu, Quanhua

Abstract

Anti-jamming technology holds an important position in the field of radar research. The main-lobe jamming has emerged as a significant threat to radar system performance. To address the imperative need for radar main-lobe jamming suppression, this article proposes a cascaded least mean square (LMS) jamming suppression method. Compared with the traditional fast-time LMS filtering method, the proposed method can offer notable enhancements in both signal-to-interference-plus-noise ratio (SINR) and signal-to-noise ratio (SNR). This article also employs a low-cost receiver array to carry out the main-lobe jamming suppression verification. The results of the experiment prove the effectiveness of the proposed method. Moreover, the utilization of the low-cost and lightweight receiving array can be applied to other jamming suppression processes, thereby providing an alternative technical strategy for main-lobe jamming suppression.

Published
2023
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12. Multiobservation-Based Closely Spaced Extended Target Angle Estimation Method

Author

Liang, Zhennan, Ma, Teng, Chang, Shaoqiang, Zhang, Kaixiang, Liu, Haibo, and Liu, Quanhua

Abstract

Highly accurate target angle estimation is essential for target tracking. In closely spaced scenarios, when multiple targets are close to each other, their measurement points will be located in the same range-azimuth cell. In particular, under wideband radar conditions, the target is expanded into multiple scattering points. When multiple extended targets are located close to each other in space, there may be multiple target scattering points falling within the same range-azimuth cell. In this case, there is a large bias in the estimated angle of each extended target, which affects the accuracy of the estimated angle of the closely spaced extended target. To solve this problem, this article proposes a closely spaced extended target angle estimation method under multiple observations. The proposed method utilizes the principle of invariance of extended target scattering characteristics between adjacent pulses to predict the scattering of extended target echoes and employs maximum likelihood estimation (MLE) to estimate the extended target angle. The effectiveness and feasibility of the proposed method are evaluated through experimental simulation.

Published
2023
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14. Slow-Time MIMO Waveform Design Using Pulse-Agile-Phase-Coding for Range Ambiguity Mitigation.

Author

Chang, Shaoqiang, Yang, Fawei, Liang, Zhennan, Ren, Wei, Zhang, Hao, and Liu, Quanhua

Subjects
*EVOLUTIONARY algorithms, *MIMO radar, *AMBIGUITY, *SIGNAL processing
Abstract

This paper proposed a Pulse-Agile-Phase-Coding slow-time MIMO (PAPC-st-MIMO) waveform, where the phase-coded signal is utilized as the intra-pulse modulation of the slow-time MIMO waveform. Firstly, the signal model of the proposed waveform is derived. To improve the orthogonality of the phase-coded waveform sets, a novel hybrid evolutionary algorithm based on Cyclic Algorithm New (CAN) is proposed. After the optimization process of the phase-coded waveform sets, the signal processing method of the PAPC-st-MIMO waveform is derived. Finally, the effectiveness of the proposed method is verified with a simulation experiment. The mitigation ratio of the near-range detection waveform can achieve −30 dB, while the long-range detection waveform can achieve −35 dB. This approach ensures waveform orthogonality while enabling the slow-time MIMO waveform to achieve distance selectivity. By conducting joint pulse-Doppler processing across multiple range segments, range ambiguity can be suppressed, increasing the system's Pulse Repetition Frequency (PRF) without introducing ambiguity. [ABSTRACT FROM AUTHOR]

Published
2023
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16. Practical investigation of a MIMO radar system capabilities for small drones detection

Author

Yang, Fawei, Xu, Feng, Fioranelli, Francesco, Le Kernec, Julien, Chang, Shaoqiang, and Long, Teng

Abstract

The latest progress of the multiple-input multiple-output (MIMO) radar system developed for small drones detection at Beijing Institute of Technology is presented herein. A low-cost S-band MIMO scanning radar system is designed for the detection of small drones. A practical design optimisation and implementation of a sparse array covering the whole airspace, and a target-based MIMO radar array calibration method to improve the signal-to-noise ratio of the target are proposed. An experiment in the microwave chamber was conducted to verify the designed sparse-array beam-pattern, and measurement campaigns for small drones were performed to test the system performance where the radar achieved detection and tracking of a small DJI-Phantom 4 drone at a range of up to 5 km. Target features, including micro-Doppler and radar cross-section signatures were extracted to assist target classification. The experimental results indicate that the system has promising capability in small drones detection and tracking, despite the challenges of low dwell time on targets due to the scanning nature of the system.

Published
2021

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