Waveform Analysis and Optimization for Radar Coincidence Imaging with Modeling Error

Zhou, Xiaoli; Wang, Hongqiang; Cheng, Yongqiang; Qin, Yuliang; Chen, Haowen

doi:10.1155/2017/7253179

Cited by 7 publications

(7 citation statements)

References 33 publications

(44 reference statements)

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“…The metamaterial antenna in super-resolution imaging usually refers to a two-dimensional modulation array of metamaterials formed by a combination of metamaterial units. Compared with conventional antennas, a metamaterial modulation array can be flexibly designed to achieve electromagnetic wave spatial modulation [ 7 , 8 , 9 , 10 , 11 ]. Theoretical and experimental results show that metamaterials have good performance in refraction, polarization rotation, asymmetric transmission and broadband design [ 12 , 13 ].…”

Section: Metamaterials Antennasmentioning

confidence: 99%

Low-Cost Metamaterial Antennas: Forward-Looking Imaging Experiment and Analysis

Ruan

Liu

Zhang

et al. 2022

Sensors

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A phase error correction method is proposed to compensate for the phase error in super-resolution correlated imaging based on metamaterial antennas. The varying carrier frequencies of a metamaterial antenna can generate the random radiation field for super-resolution correlation imaging, but the variation of the signal carrier frequency leads to large phase errors in the imaging results. In this proposed method, the sampling matrix in the super-resolution correlated imaging algorithm is used to compensate for the phase errors. Each element of the matrix is multiplied by a compensation phase corresponding to the phase error, and the error is subtly removed from the algorithm. In the experiment, the antenna pattern at each frequency of the metamaterial antenna is measured and recorded. In addition, an external field experiment is also carried out, and the collected data are imaged with the improved algorithm. Experimental results show that this technology can effectively solve the effect of phase errors on imaging results caused by signal carrier frequency changes.

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Section: Metamaterials Antennasmentioning

confidence: 99%

Low-Cost Metamaterial Antennas: Forward-Looking Imaging Experiment and Analysis

Ruan

Liu

Zhang

et al. 2022

Sensors

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“…Among the different random modulations, random Frequency Hopping (FH) signals are most commonly employed because of the constant-envelope feature and the frequency agility [15,22,23]. An optimization algorithm was adopted to acquire a well-behaved frequency code design of the FH signals based on minimizing the condition number of the sensing matrix [24]. Temporal-Spatial Distribution Entropy (TSDE) was proposed in [25] as the optimization target of the joint design of waveform parameters and array configuration.…”

Section: Introductionmentioning

confidence: 99%

Microwave Staring Correlated Imaging Method Based on Steady Radiation Fields Sequence

Zhang

Yuan

Jiang

et al. 2020

Sensors

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Microwave Staring Correlated Imaging (MSCI) is a newly proposed computational high-resolution imaging technique. The imaging performance of MSCI with the existence of modeling errors depends on the properties of the imaging matrix and the relative perturbation error resulted from existing errors. In conventional transient-radiation-fields-based MSCI, which is commonly accomplished by utilizing random frequency-hopping (FH) waveforms, the multiple transmitters should be controlled individually and simultaneously. System complexity and control difficulty are hence increased, and various types of modeling errors are introduced as well. The computation accuracy of radiation fields is heavily worsened by the modeling errors, and the transient effect makes it hard to take direct and high-precision measurements of the radiation fields and calibrate the modeling errors with the measuring result. To simplify the system complexity and reduce error sources, in this paper, steady-radiation-fields-sequence-based MSCI (SRFS-MSCI) method is proposed. The multiple transmitters are excited with coherent signals at the same observation moment, with the signal frequency varying in the whole frequency band during the imaging process. By elaborately designing the array configuration and the amplitude and phase sequences of the coherent transmitters, the SRFS-MSCI is thus implemented. Comparing the system architecture of the proposed SRFS-MSCI with the conventional random FH-based MSCI, it can be found that the proposed method significantly reduces the number of baseband modules and simplifies the system architecture and control logic, which contributes to reducing error sources such as baseband synchronization errors and decreasing deterioration caused by error cascade. To further optimize the design parameters in the proposed SRFS-MSCI system, the Simulated Annealing (SA) algorithm is utilized to optimize the amplitude sequences, the phase sequences, and the antenna positions individually and jointly. Numerical imaging experiments and real-world imaging experiment demonstrate the effectiveness of the proposed SRFS-MSCI method that recognizable high-resolution recovery results are obtained with simplified system structure and optimized system parameters.

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“…Among the above mentioned randomly modulated waveforms, random Frequency Hopping (FH) signal is most commonly employed because of its constant-envelope feature and frequency agility, which makes FH signal practical and manageable in MSCI systems. An optimization algorithm was adopted to acquire a well-behaved frequency code design of the FH signals based on minimizing the condition number of the imaging matrix [13]. In addition to waveform design, optimizing the design of the transmitting array also contributes to improving stochastic characteristic of TSSRF.…”

Section: Introductionmentioning

confidence: 99%

Microwave Staring Correlated Imaging Based on Time-Division Observation and Digital Waveform Synthesis

et al. 2020

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As a newly proposed high resolution computational imaging technique, Microwave Staring Correlated Imaging (MSCI) requires elaborate design of the temporal-spatial stochastic radiation fields (TSSRF). Conventional implementation of MSCI radiation source consists of multiple transmitters configuration and simultaneous emitting scheme, which remains underutilization of the available design resources. In this paper, a time-division MSCI (TD-MSCI) method is proposed to virtually generate the TSSRF and make further use of the available design resources. Different from convention simultaneously transmitting based MSCI, the detection scheme in TD-MSCI is achieved by alternately transmitting of each transmitter, rather than simultaneous transmission of multiple transmitters. Echo enhancement is conducted to improve the SNR level of the echo waveform and to resolve the power coastdown caused by single transmitting scheme. Unused combinations of existing resources are digitally synthesized in computer rather than taking extra observations in actual physical environment. After the processing of time division observation, echo enhancement and digital waveform synthesis, extending TSSRF with better stochastic characteristics are generated, and improved imaging performance is obtained. Numerical imaging experiments and preliminary real-world imaging experiment verify the effectiveness of the proposed TD-MSCI, demonstrating that the proposed method increases the flexibility in radiation source design and decreases the detection costs.

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Waveform Analysis and Optimization for Radar Coincidence Imaging with Modeling Error

Cited by 7 publications

References 33 publications

Low-Cost Metamaterial Antennas: Forward-Looking Imaging Experiment and Analysis

Low-Cost Metamaterial Antennas: Forward-Looking Imaging Experiment and Analysis

Microwave Staring Correlated Imaging Method Based on Steady Radiation Fields Sequence

Microwave Staring Correlated Imaging Based on Time-Division Observation and Digital Waveform Synthesis

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