scholarly journals Design and Imaging of Ground-Based Multiple-Input Multiple-Output Synthetic Aperture Radar (MIMO SAR) with Non-Collinear Arrays

2017 ◽  
Author(s):  
Cheng Hu ◽  
Jingyang Wang ◽  
Weiming Tian ◽  
Tao Zeng ◽  
Rui Wang
Keyword(s):  
Coupling Effect ◽  
Near Field ◽  
Multiple Input Multiple Output ◽  
Far Field ◽  
Imaging Result ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Edge Points ◽  
Virtual Array ◽  
Field Edge

MIMO (multiple-input multiple-output) radar provides much more flexibility than the traditional radar for its ability to realize far more observation channels than the actual number of T/R (transmit and receive) elements. Designing the array of MIMO imaging radar, the commonly used virtual array theory generally assumes that all elements are placed on the same line. However, due to the physical size of the antennas and coupling effect between T/R elements, a certain height difference between T/R arrays is essential, resulting in the defocusing of edge points of the scene. On the other hand, the virtual array theory implies far-field approximation, leading to inevitable high grating lobes in the imaging result of near-field edge points of the scene observed by common MIMO array. To tackle these problems, this paper derives the relationship between target’s PSF (point spread function) and pattern of T/R arrays, by which the design criterion of near-field imaging MIMO array is presented. Firstly, the proper height between T/R arrays is designed to focus the near-field edge points well. Secondly, the far-field array is modified to suppress the grating lobes in the near-field area. Finally, the validity of the proposed methods is verified by simulations and an experiment.

scholarly journals A Novel MIMO–SAR Solution Based on Azimuth Phase Coding Waveforms and Digital Beamforming

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3374 ◽  
Author(s):  
Fang Zhou ◽  
Jiaqiu Ai ◽  
Zhangyu Dong ◽  
Jiajia Zhang ◽  
Mengdao Xing
Keyword(s):  
Multiple Input Multiple Output ◽  
Three Dimensional ◽  
Spatial Diversity ◽  
Reconstruction Method ◽  
Digital Beamforming ◽  
Phase Coding ◽  
Imaging Result ◽  
Multiple Input ◽  
Input Multiple Output ◽  
The Time Domain

In multiple-input multiple-output synthetic aperture radar (MIMO–SAR) signal processing, a reliable separation of multiple transmitted waveforms is one of the most important and challenging issues, for the unseparated signal will degrade the performance of most MIMO–SAR applications. As a solution to this problem, a novel APC–MIMO–SAR system is proposed based on the azimuth phase coding (APC) technique to transmit multiple waveforms simultaneously. Although the echo aliasing occurs in the time domain and Doppler domain, the echoes can be separated well without performance degradation by implementing the azimuth digital beamforming (DBF) technique, comparing to the performance of the orthogonal waveforms. The proposed MIMO–SAR solution based on the APC waveforms indicates the feasibility and the spatial diversity of the MIMO–SAR system. It forms a longer baseline in elevation, which gives the potential to expand the application of MIMO–SAR in elevation, such as improving the performance of multibaseline InSAR and three-dimensional SAR imaging. Simulated results on both a point target and distributed targets validate the effectiveness of the echo separation and reconstruction method with the azimuth DBF. The feasibility and advantage of the proposed MIMO–SAR solution based on the APC waveforms are demonstrated by comparing with the imaging result of the up- and down-chirp waveforms.

Conjugate ESPRIT for MIMO Radar without Using Non-Circular Signals

2014 ◽  
Vol 513-517 ◽  
pp. 3850-3854
Author(s):  
Jian Feng Li ◽  
Wei Yang Chen ◽  
Xiao Fei Zhang
Keyword(s):  
Data Model ◽  
Multiple Input Multiple Output ◽  
Mimo Radar ◽  
Rotational Invariance ◽  
Joint Estimation ◽  
Signal Parameters ◽  
Direction Of Departure ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Virtual Array

Without using non-circular signals, conjugate estimation of signal parameters via rotational invariance technique (ESPRIT) for joint estimation of direction of departure (DOD) and direction of arrival (DOA) in bistatic multiple-input multiple-output (MIMO) radar is proposed. The characteristics of the Vandermonde-like matrix are employed to expand the virtual array of MIMO radar. Then the rotational invariance in the signal subspace is exploited to get the automatically paired estimations of angles. The proposed algorithm works with the same data model as that of ESPRIT, and has better angle estimation performance and can detect more targets than ESPRIT. Simulation results verify the usefulness of our approach.

scholarly journals Joint Phased-MIMO and Nested-Array Beamforming for Increased Degrees-of-Freedom

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Chenglong Zhu ◽  
Hui Chen ◽  
Huaizong Shao
Keyword(s):  
Degrees Of Freedom ◽  
Phased Array ◽  
Multiple Input Multiple Output ◽  
Doa Estimation ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Virtual Array ◽  
The Difference ◽  
Array Beamforming ◽  
Error Simulation

Phased-multiple-input multiple-output (phased-MIMO) enjoys the advantages of MIMO virtual array and phased-array directional gain, but it gets the directional gain at a cost of reduced degrees-of-freedom (DOFs). To compensate the DOF loss, this paper proposes a joint phased-array and nested-array beamforming based on the difference coarray processing and spatial smoothing. The essence is to use a nested-array in the receiver and then fully exploit the second order statistic of the received data. In doing so, the array system offers more DOFs which means more sources can be resolved. The direction-of-arrival (DOA) estimation performance of the proposed method is evaluated by examining the root-mean-square error. Simulation results show the proposed method has significant superiorities to the existing phased-MIMO.

scholarly journals Design and Analysis of Ultra-Wideband Split Transmit Virtual Aperture Array for Through-the-Wall Imaging

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Biying Lu ◽  
Yang Zhao ◽  
Xin Sun ◽  
Zhimin Zhou
Keyword(s):  
Near Field ◽  
Multiple Input Multiple Output ◽  
Equivalence Theorem ◽  
Ultra Wideband ◽  
Multiple Input ◽  
Spread Function ◽  
Input Multiple Output ◽  
Active Imaging ◽  
Imaging Performance ◽  
Wall Imaging

The concept of virtual aperture and the point spread function for designing and characterizing ultra-wideband near-field multiple-input multiple-output active imaging array are investigated. Combining the approach of virtual aperture desynthesis with the monostatic-to-bistatic equivalence theorem, a kind of linear UWB MIMO array, the split transmit virtual aperture (STVA) array, was designed for through-the-wall imaging. Given the virtual aperture, the STVA array is the shortest in physical aperture length. The imaging performance of the designed STVA array in the near field is fully analyzed through both numerical and measured data. The designed STVA array has been successfully applied to imaging moving targets inside buildings.

scholarly journals 45 degree arrangement of compact array antenna for MIMO application

2019 ◽  
Vol 15 (2) ◽  
pp. 838
Author(s):  
M. F. Ismail ◽  
H. A. Majid ◽  
C. Macwright ◽  
M. N. A. H. Shaabani ◽  
M. S. Mohd ◽  
...  
Keyword(s):  
Mutual Coupling ◽  
Coupling Effect ◽  
Multiple Input Multiple Output ◽  
Rectangular Array ◽  
Mimo Antenna ◽  
Compact Antenna ◽  
Microstrip Patch ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Compact Array

A study on the compact array microstrip patch antenna for multiple-input multiple-output (MIMO) communication system based on the antenna arrangement is performed. The 2.45 GHz rectangular array are arranged in 45 degree slanted inward and outward for each other to reduce the mutual coupling effect between the patches. The antenna properties are analyzed and compact antenna design is determined based on the simulation results. The results show the antennas can very compact while maintaining low mutual coupling. The gain of the MIMO antenna is 11.3 dBi. The simulated and tested return losses, together with the radiation patterns, are presented and discussed.

scholarly journals Optimizations for robust low sidelobe beamforming of bistatic multiple-input multiple-output virtual array

2014 ◽  
Vol 63 (18) ◽  
pp. 188401
Author(s):  
Huang Cong ◽  
Sun Da-Jun ◽  
Zhang Dian-Lun ◽  
Teng Ting-Ting
Keyword(s):  
Multiple Input Multiple Output ◽  
Low Sidelobe ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Virtual Array

scholarly journals Fourier Compatible Near-Field Multiple-Input Multiple-Output Terahertz Imaging with Sparse Non-Uniform Apertures

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Amir Masoud Molaei ◽  
Shaoqing Hu ◽  
Vasiliki Skouroliakou ◽  
Vincent Fusco ◽  
Xiaodong Chen ◽  
...  
Keyword(s):  
Near Field ◽  
Multiple Input Multiple Output ◽  
Terahertz Imaging ◽  
Multiple Input ◽  
Input Multiple Output
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