4,586 results on '"RADAR"'
Search Results
2. Gait‐based human recognition based on millimetre wave multiple input multiple output radar point cloud constructed using velocity‐depth‐time
- Author
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Xianxian He, Yunhua Zhang, and Xiao Dong
- Subjects
gait analysis ,millimetre wave radar ,MIMO radar ,object recognition ,radar target recognition ,Telecommunication ,TK5101-6720 - Abstract
Abstract Gait recognition is to recognise different individuals based on their faint differences of gait characteristics, which is different from and more challengeable than the recognition of human activities based on relatively bigger differences between different motions. Existing millimetre‐wave Multiple Input Multiple Output radar point cloud data contains time‐varying three‐dimensional spatial positions, velocity, and intensity information. How to enhance the accuracy of gait recognition by effectively utilising the available radar point cloud data has become an attractive research topic in recent years. A velocity‐depth‐time (VDT) based point cloud construction method for millimetre‐wave Multiple Input Multiple Output radar is proposed for gait recognition application, which can not only alleviate the sparsity problem of mmWave point cloud but also make the constructed point cloud to exhibit temporal structural features of micro‐motions, and therefore enable the successful application of PointNet++ to mmWave‐MIMO point cloud gait recognition. New point clouds are constructed by the proposed method using public gait recognition datasets of 10 and 20 individuals from mmWave‐MIMO radar, which are used to conduct gait recognition experiments using PointNet++. The results show that the point clouds constructed based on VDT are more conducive to the gait recognition task. Even using the classic PointNet++ model, which is not specially designed for radar point clouds, high recognition accuracy can be achieved for gait recognition tasks. The recognition accuracies are improved by 11% and 12% in this work for datasets of 10 and 20 individuals, respectively, compared with the 84% and 80% achieved by the traditional method using the same dataset and the same PointNet++ model, while the accuracies are improved by 5% and 12%, respectively, compared with the 90% and 80% achieved by the original dataset thesis method corresponding to 10‐individual and 20‐individual datasets.
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- 2024
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- View/download PDF
3. Sequence optimisation for compressed sensing CDMA MIMO radar via mutual coherence minimisation
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Saravanan Nagesh, María A. González‐Huici, Andreas Bathelt, Miguel Heredia Conde, and Joachim Ender
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compressed sensing ,MIMO radar ,phase modulation ,radar waveforms ,Telecommunication ,TK5101-6720 - Abstract
Abstract The authors focus on the waveform design for Code Division Multiple Access Multiple Input Multiple Output (CDMA‐MIMO) radar systems, with a specific emphasis on Compressed Sensing (CS) based target estimation. The selection of an appropriate waveform is a critical determinant in the effectiveness of estimation algorithms. Recent studies show the possibilities of optimising waveform parameters to improve the efficiency of CS based estimation. The authors introduce an optimisation framework designed to modify the phase components of code sequences used in CS‐CDMA MIMO radar systems. The objective of this optimisation is to minimise the l∞ norm of off‐diagonal elements within the Gramian matrix of the underlying sensing matrix, focusing on phase modulation of the waveform. Solving this optimisation problem requires dealing with a non‐convex, combinatorial and non‐linear scenario. Simulated Annealing is employed as the solution technique. To assess the effectiveness of the proposed optimisation approach, the resulting optimised sequence is rigorously compared against well‐established Hadamard and Gold sequences across various performance metrics. These metrics encompass correlation properties, ambiguity function behaviour, recovery percentage and recovery error. The study demonstrates that the generated poly‐phase sequences outperform existing sequences, leading to significantly improved target reconstruction results in the context of CDMA‐MIMO radar systems with CS‐based estimation.
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- 2024
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4. Phase response constrained symbol‐level waveform design for dual‐functional radar‐communication systems.
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Zhang, Tingxiao, Zhao, Yongbo, and Liu, Donghe
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RADAR signal processing , *MIMO radar , *BLOCK designs , *QUALITY of service , *DEGREES of freedom , *MOBILE communication systems , *RADAR - Abstract
In this letter, a novel algorithm is proposed to design symbol‐level waveform for dual‐functional radar‐communication (DFRC) systems with low range sidelobe. Different from current schemes design waveform at the block level, a phase response constraint is introduced at the symbol level to provide an additional degree of freedom to decrease the range sidelobe in the pulse compression procedure, which is highly desired in radar systems. In particular, the phase response at the target direction is constrained to be similar to the given reference phase, and the matching error between the designed beampattern and the desired one is minimized subject to the constant modulus constraint. Furthermore, to guarantee the quality of service for communication, constructive interference is exploited at the symbol level for each communication user. An alternating direction method of multipliers algorithm is also proposed to solve the resulting nonconvex optimization problem with tractable subproblems solved sufficiently by the manifold optimization and standard quadratic problem. Numerical simulation results demonstrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Universal Software Only Radar with All Waveforms Simultaneously on a Single Platform.
- Author
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Kozlov, Vitali, Kharchevskii, Anton, Rebenshtok, Eran, Bobrovs, Vjaceslavs, Salgals, Toms, and Ginzburg, Pavel
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CONTINUOUS wave radar , *RADAR , *DATA libraries , *MIMO radar - Abstract
Abstract: While software-defined radars can switch their transmitted waveform on the go, they cannot transmit all waveforms at the same time, meaning they must balance the advantages and drawbacks of each configuration. Here, we propose theoretically and demonstrate experimentally the universal radar, which can apply the desired waveform in the post-processing stage after the physical measurement has been performed. This method also allows using a single measurement of a scene to design and test any other radar in complex scenarios without having to take it to the field. The method is based on post-processing the frequency response measured by a synthetically broadband stepped-frequency continuous wave radar, such as a vector network analyzer. An algorithm for overcoming distortions due to moving targets is derived as well. This approach not only provides an ultra-wideband software-only defined radar, but it also enables the acquired data from any measured site to be used for the design and analysis of almost any other future radar system, significantly cutting the time and cost of new developments. The method suggests the creation of radar raw data repositories that can be shared across diversely different radar platforms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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6. A Time-Domain Doppler Estimation and Waveform Recovery Approach with Iterative and Ensemble Techniques for Bi-Phase Code in Radar Systems.
- Author
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Youssef, Ahmed, Moa, Belaid, and Driessen, Peter F.
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DOPPLER effect , *RADAR , *SOFTWARE radio , *SIGNAL-to-noise ratio , *MIMO radar , *ESTIMATION theory - Abstract
This paper presents a novel, cost-effective technique for estimating the Doppler effect in the time domain using a single pulse and subsequently leveraging the precise Doppler value to recover the radar waveform. The proposed system offers several key advantages over existing techniques, including the ability to calculate the target speed without any frequency ambiguity and the ability to detect a wide range of target speeds. These two features are not available in any existing techniques, including the conventional moving target detection (MTD) processor. To ensure improved accuracy and robust estimation, the system employs ensemble and iterative techniques by recursively and efficiently reducing the Doppler residues from the signal. Furthermore, the proposed system demonstrates effective signal recovery of a well-known bi-phase code shape at low signal-to-noise ratios in just a few iterations. The performance evaluation of the new algorithm demonstrates its practicability and its superiority over traditional radar systems. Implementation on software-defined radio (SDR) reveals that the proposed system excels in Doppler estimation and signal recovery at low SNRs, demonstrating promising results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. Existence of optimal virtual element weights for mmWave FMCW MIMO radar based heart rate estimation.
- Author
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Gilles Yowel, Massala Mboyi and Han, Jung‐Hoon
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HEART beat , *MIMO radar , *ANTENNAS (Electronics) , *MEDICAL electronics , *HEART diseases , *SKIN diseases - Abstract
Measuring heart rate is a critical component of assessing cardiac health and detecting potential heart diseases at an early stage. Various sensors, including electrocardiogram and photoplethysmograph, are commonly employed for this purpose. However, these conventional methods necessitate direct contact with the patient's skin which may be impractical or uncomfortable in situations involving patients with skin diseases or burn injuries. To address these limitations, a concerted effort has been to develop non‐contact methods leveraging frequency‐modulated continuous‐wave multiple‐input multiple‐output radar systems. Recent studies have illustrated the sensitivity of the phase component of received signals to micro‐motion, presenting a promising avenue for effective heart rate estimation. However, existing literature predominantly focuses on single‐antenna setups, overlooking the potential benefits offered by multiple‐input multiple‐output systems, which provide diverse channels with varying precision levels. This correspondence introduces a novel phase extraction model grounded in the argument of the analytic signal derived from both in‐phase and quadrature channels. Furthermore, leveraging the normal equation, we establish the feasibility of optimizing weights assigned to individual virtual antennas to achieve a robust approximation of ground truth data. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Characterization and Application of S-Band Polarimetric Radar and X-Band Phased Array Radar for a Tornadic Storm Event on June 16, 2022.
- Author
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CHEN Bing-hong, FU Pei-ling, ZHANG Yu, SU Ran, TIAN Cong-cong, and CHEN Chao
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TORNADOES , *PHASED array radar , *RADAR meteorology , *SEVERE storms , *MIMO radar , *SPATIAL resolution , *LEAD time (Supply chain management) , *RADAR - Abstract
The X-band phased array radar offers faster scanning speed and higher spatial resolution compared to the S-band radar, making it capable of enhancing tornado monitoring and early warning capabilities. This study analyzed the characteristics and nowcasting signals of a tornado case that occurred on June 16, 2022 in the Guangzhou region. Our findings indicate that the violent contraction of rotation radius and the dramatic increase in rotation speed were important signal characteristics associated with tornado formation. The X-band phased array radar, with its high temporal and spatial resolution, provided an opportunity to capture early warning signals from polarimetric characteristics. The X-band phased array radar demonstrated noteworthy ability to identify apparent tornado vortex signature (TVS) features in a 10-minute lead time, surpassing the capabilities of the CINRAD/SA radar. Additionally, due to its higher scanning frequency, the Xband phased-array radar was capable of consistently identifying TVS with shorter intervals, enabling a more precise tracking of the tornado's path. The application of professional radars, in this case, provides valuable insights for the monitoring of evolutions of severe local storms and even tornadoes and the issuance of early warning signals. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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9. Performance analysis of ground‐based long baseline radar distributed systems for space situational awareness
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Sebastián Díaz Riofrío, Simão DaGraça Marto, Christos Ilioudis, Massimiliano Vasile, and Carmine Clemente
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MIMO radar ,radar ,radar signal processing ,space debris ,Telecommunication ,TK5101-6720 - Abstract
Abstract Detection of space objects is a key component of space situational awareness, which could help prevent and minimise space collisions. While there have been lots of radar systems designed to detect space objects, few of them have dealt with long baseline distributed bistatic pairs. The authors focus on the feasibility of long baseline bistatic radars, which can be extended for the multistatic case; and the performance of the multistatic system for a target at different altitudes assuming one transmitter over three different scenarios: a cluster of receivers, receivers spread throughout the world and the combination of the two previous cases. To analyse the performance the multiple‐input‐multiple‐output (MIMO) ambiguity function (AF) will be employed. The results of the MIMO AF show how the fusion of different bistatic pairs improves the detection capabilities. Moreover, when the different radar measurements are coherently summed in the MIMO AF, the uncertainty on the location of the target is reduced.
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- 2024
- Full Text
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10. Performance analysis of ground‐based long baseline radar distributed systems for space situational awareness.
- Author
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Díaz Riofrío, Sebastián, Da Graça Marto, Simão, Ilioudis, Christos, Vasile, Massimiliano, and Clemente, Carmine
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BISTATIC radar , *SITUATIONAL awareness , *RADAR , *RADAR signal processing , *MIMO radar , *SYSTEMS design - Abstract
Detection of space objects is a key component of space situational awareness, which could help prevent and minimise space collisions. While there have been lots of radar systems designed to detect space objects, few of them have dealt with long baseline distributed bistatic pairs. The authors focus on the feasibility of long baseline bistatic radars, which can be extended for the multistatic case; and the performance of the multistatic system for a target at different altitudes assuming one transmitter over three different scenarios: a cluster of receivers, receivers spread throughout the world and the combination of the two previous cases. To analyse the performance the multiple‐input‐multiple‐output (MIMO) ambiguity function (AF) will be employed. The results of the MIMO AF show how the fusion of different bistatic pairs improves the detection capabilities. Moreover, when the different radar measurements are coherently summed in the MIMO AF, the uncertainty on the location of the target is reduced. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. A Novel Generalized Nested Array MIMO Radar for DOA Estimation with Increased Degrees of Freedom and Low Mutual Coupling.
- Author
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Yang, Zhongtian, Bi, Zhengyang, Chen, Ye, and Hao, Honghao
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MIMO radar , *DEGREES of freedom , *DIRECTION of arrival estimation , *SIGNAL processing , *POSITION sensors , *ARRAY processing - Abstract
In array signal processing, the mutual coupling among physical sensors can inevitably affect the estimation of the direction of arrival (DOA). Despite the fact that multiple-input and multiple-output (MIMO) radar can provide greater degrees of freedom (DOFs), the influence of mutual coupling is largely overlooked in many current MIMO radar designs. To tackle this issue, we propose the utilization of a generalized nested array (GNA) in transmitter array and we introduce an expansion factor into the nested array in the receiver array. Thereby, a novel GNA-MIMO radar is put forward. The proposed MIMO radar offers O (N 4) consecutive DOFs with N sensors and avoids the adverse effects of high mutual coupling caused by closely located sensors. Furthermore, we derive the closed-form expressions for the position of physical sensors and the attainable consecutive DOFs of the proposed MIMO radar. Through simulation experiments, we demonstrate the superior accuracy of the proposed MIMO configuration in DOA estimation and angle resolution under the condition of mutual coupling effect. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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12. Improving estimation performance of compressive sensing‐based multiple‐input multiple‐output radar using electronic beamsteering.
- Author
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Schurwanz, Max, Mietzner, Jan, and Hoeher, Peter Adam
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MIMO radar , *TRACKING radar , *RADAR signal processing , *RADAR , *ELECTRONIC systems , *DRONE aircraft , *ANTENNA arrays - Abstract
Two‐dimensional direction‐of‐arrival (DoA) estimation in azimuth and elevation via radar systems equipped with uniform rectangular arrays (URAs) will play an important role in various application areas—most distinctively in future urban air mobility settings with unmanned aerial vehicles. A key factor is the fast and reliable provision of target detections in terms of range and DoA for safe autonomous operation of the vehicle using on‐board antenna arrays with compact installation size. The authors present a technique for improving the performance of DoA estimation using compressive sensing in conjunction with multiple‐input multiple‐output arrays with electronically steered beams in the transmit direction. The simulation study investigates the impact of different design considerations on radar signal processing performance. An optimisation of a radar system using electronic beamsteering in the transmit domain is presented numerically. Based on the architecture of the URAs used, performance and detection accuracy can be improved. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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13. Spatial–Temporal Joint Design and Optimization of Phase-Coded Waveform for MIMO Radar.
- Author
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Lei, Wei, Zhang, Yue, Chen, Zengping, Chen, Xiaolong, and Song, Qiang
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MIMO radar , *LEAST squares , *DEGREES of freedom , *NONLINEAR equations , *RADAR , *PROBLEM solving - Abstract
By simultaneously transmitting multiple different waveform signals, a multiple-input multiple-output (MIMO) radar possesses higher degrees of freedom and potential in many aspects compared to a traditional phased-array radar. The spatial–temporal characteristics of waveforms are the key to determining their performance. In this paper, a transmitting waveform design method based on spatial–temporal joint (STJ) optimization for a MIMO radar is proposed, where waveforms are designed not only for beam-pattern matching (BPM) but also for minimizing the autocorrelation sidelobes (ACSLs) of the spatial synthesis signals (SSSs) in the directions of interest. Firstly, the STJ model is established, where the two-step strategy and least squares method are utilized for BPM, and the L2p-Norm of the ACSL is constructed as the criterion for temporal characteristics optimization. Secondly, by transforming it into an unconstrained optimization problem about the waveform phase and using the gradient descent (GD) algorithm, the hard, non-convex, high-dimensional, nonlinear optimization problem is solved efficiently. Finally, the method's effectiveness is verified through numerical simulation. The results show that our method is suitable for both orthogonal and partial-correlation MIMO waveform designs and efficiently achieves better spatial–temporal characteristic performances simultaneously in comparison with existing methods. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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14. Novel approaches for target parameter extraction with eigenvalue thresholding and Dolph–Chebyshev windowing in multiple‐input multiple‐output (MIMO) radar system.
- Author
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Jagtap, Sheetal G. and Kunte, Ashwini S.
- Subjects
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MIMO radar , *MARINE electronics , *RADAR , *EIGENVALUES , *MULTIPLE Signal Classification , *RADIO waves - Abstract
Summary Multiple‐input multiple‐output (MIMO) radar, employing multiple transmitters and receivers, enhances radar capabilities. It detects and tracks objects like aircraft and ships using radio waves. Compared with traditional phased‐array radar, MIMO systems offer greater flexibility, improving angular resolution and target detection. Researchers focus on direction of arrival (DoA) evaluation for closely spaced targets. Effective beamforming and accurate DoA estimation are crucial for MIMO radar performance. This study explores two methods: Capon beamforming with Dolph–Chebyshev windowing and the MUSIC algorithm with Eigenvalue thresholding. Tested under low signal‐to‐noise ratio (SNR) and fewer snapshots, these techniques notably reduce side lobes and enhance angular resolution, validated by experiments. Additionally, the suppression of side lobes significantly improves the clarity and accuracy of target detection, minimizing potential interference and false targets. This enhancement in side lobe suppression facilitates a more precise spatial differentiation between multiple targets, thus contributing to the overall effectiveness and reliability of MIMO radar systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Doppler-resilient waveform design in integrated MIMO radar-communication systems
- Author
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Zhou, Zhengchun, Liu, Bing, Shen, Bingsheng, Adhikary, Avik Ranjan, and Fan, Pingzhi
- Published
- 2024
- Full Text
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16. Waveform design of radar coincidence imaging radiation field based on image entropy.
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Zhang, Qian, Zhang, Gong, Chen, Ningwei, Xiong, Qing, Xie, Jun, and He, Yansen
- Subjects
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RADAR cross sections , *RADAR targets , *COINCIDENCE , *RADIATION , *ENTROPY , *MIMO radar , *RADAR - Abstract
Radar coincidence imaging (RCI) is a high‐resolution radar imaging mode which constructs a temporal spatial stochastic radiation field (TSSRF) and uses the correlation between reference signal and echoes for imaging. The correlation between the reference matrix and the echoes is the main factor affecting the imaging performance. In fact, radar target characteristics cause fluctuations in the radar cross section and variations in the scattering intensity of each resolution element. The latter degrades the correlation between the reference matrix and the echoes, seriously affecting the image reconstruction. This paper designs the waveform based on image entropy under fixed transmitting and receiving arrays. The targets with fluctuating scattering intensity at each resolution element are statistically modelled. Simulation results show this approach can improve the imaging performance and reduce the energy dissipation degree of the target grid. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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17. Efficiently Refining Beampattern in FDA-MIMO Radar via Alternating Manifold Optimization for Maximizing Signal-to-Interference-Noise Ratio.
- Author
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Geng, Langhuan, Li, Yong, Dong, Limeng, Tan, Yumei, and Cheng, Wei
- Subjects
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MIMO radar , *RADAR , *SIGNAL processing , *QUADRATIC programming , *BEAMFORMING , *RIEMANNIAN manifolds - Abstract
Joint transceiver beamforming is a fundamental and crucial research task in the field of signal processing. Despite extensive efforts made in recent years, the joint transceiver beamforming of frequency diverse array (FDA)-based multiple-input and multiple-output (MIMO) radar has received relatively less attention and is confronted with some tricky challenges, such as range–angle decoupling and the interaction between multiple performance metrics. In this paper, we initially derive the generalized ambiguity function of the FDA-MIMO radar to explore the intrinsic correlation between its waveform design and resolution. Following that, the joint beamforming optimization is formulated as a nonconvex bivariate quadratic programming problem (NBQP) with the aim of maximizing the Signal-to-Interference-Noise Ratio (SINR) of the FDA-MIMO radar system. Building upon this, we introduce an innovative alternating manifold optimization with nested iteration (AMO-NI) algorithm to address the NBQP. By incorporating manifold optimization into iterative updates of transmit waveform and receiving filter, the AMO-NI algorithm considers the interdependencies among the optimization variables. The algorithm efficiently and expeditiously finds global optimum solutions within a finite number of iterations. Compared with other methods, our approach yields a superior beampattern and higher SINR. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Low-Complexity 2D-DOD and 2D-DOA Estimation in Bistatic MIMO Radar Systems: A Reduced-Dimension MUSIC Algorithm Approach.
- Author
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Ahmad, Mushtaq, Zhang, Xiaofei, Lai, Xin, Ali, Farman, and Shi, Xinlei
- Subjects
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MULTIPLE Signal Classification , *BISTATIC radar , *MIMO radar , *MIMO systems , *ESTIMATION theory , *COMPUTATIONAL complexity - Abstract
This paper presents a new technique for estimating the two-dimensional direction of departure (2D-DOD) and direction of arrival (2D-DOA) in bistatic uniform planar array Multiple-Input Multiple-Output (MIMO) radar systems. The method is based on the reduced-dimension (RD) MUSIC algorithm, aiming to achieve improved precision and computational efficiency. Primarily, this pioneering approach efficiently transforms the four-dimensional (4D) estimation problem into two-dimensional (2D) searches, thus reducing the computational complexity typically associated with conventional MUSIC algorithms. Then, exploits the spatial diversity of array response vectors to construct a 4D spatial spectrum function, which is crucial in resolving the complex angular parameters of multiple simultaneous targets. Finally, the objective is to simplify the spatial spectrum to a 2D search within a 4D measurement space to achieve an optimal balance between efficiency and accuracy. Simulation results validate the effectiveness of our proposed algorithm compared to several existing approaches, demonstrating its robustness in accurately estimating 2D-DOD and 2D-DOA across various scenarios. The proposed technique shows significant computational savings and high-resolution estimations and maintains high precision, setting a new benchmark for future explorations in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Design of multiple‐input multiple‐output radar amplitude‐bounded waveforms with desired ambiguity function based on sequential quadratic programming
- Author
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Wenyan Wei, Yinsheng Wei, and Lei Yu
- Subjects
gradient methods ,MIMO ambiguity function ,MIMO radar ,optimisation ,radar waveforms ,waveform diversity ,Telecommunication ,TK5101-6720 - Abstract
Abstract The transmit waveform with ambiguity function specifications in the range‐Doppler plane has been of great interest in traditional single antenna radar systems in recent years. This paper considers the design of waveform sets with a desired slow‐time ambiguity function for multiple‐input multiple‐output radar. Specifically, it is desirable that the ambiguity function has low sidelobes where clutter occurs, as this reduces the impact of the clutter on target detection. Instead of unimodular waveforms, the authors consider amplitude modulation signals and introduce the bound constraint on signal amplitudes into the optimisation for the consideration of transmitter efficiency. The design problem is formulated as minimising the weighted integrated sidelobes level of the ambiguity function over the range‐Doppler plane under bound constraints. The resulting problem has a highly non‐linear objective function and is constrained by bound constraints and quadratic equality (constant energy) constraints, making it difficult to solve. The authors develop an efficient algorithm based on the sequential quadratic programming technique and non‐linear conjugate gradient method to solve it. Simulation results show that the proposed algorithm is superior to the existing methods.
- Published
- 2023
- Full Text
- View/download PDF
20. Existence of optimal virtual element weights for mmWave FMCW MIMO radar based heart rate estimation
- Author
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Massala Mboyi Gilles Yowel and Jung‐Hoon Han
- Subjects
biomedical electronics ,MIMO radar ,radar applications ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Abstract Measuring heart rate is a critical component of assessing cardiac health and detecting potential heart diseases at an early stage. Various sensors, including electrocardiogram and photoplethysmograph, are commonly employed for this purpose. However, these conventional methods necessitate direct contact with the patient's skin which may be impractical or uncomfortable in situations involving patients with skin diseases or burn injuries. To address these limitations, a concerted effort has been to develop non‐contact methods leveraging frequency‐modulated continuous‐wave multiple‐input multiple‐output radar systems. Recent studies have illustrated the sensitivity of the phase component of received signals to micro‐motion, presenting a promising avenue for effective heart rate estimation. However, existing literature predominantly focuses on single‐antenna setups, overlooking the potential benefits offered by multiple‐input multiple‐output systems, which provide diverse channels with varying precision levels. This correspondence introduces a novel phase extraction model grounded in the argument of the analytic signal derived from both in‐phase and quadrature channels. Furthermore, leveraging the normal equation, we establish the feasibility of optimizing weights assigned to individual virtual antennas to achieve a robust approximation of ground truth data.
- Published
- 2024
- Full Text
- View/download PDF
21. Guest Editorial: Advancements and future trends in noise radar technology.
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Wasserzier, Christoph, Savci, Kubilay, Masikowski, Łukasz, Galati, Gaspare, and Pavan, Gabriele
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RADAR ,INTERFERENCE suppression ,RADAR signal processing ,RADAR interference ,MIMO radar ,NOISE ,DIGITAL electronics ,MILITARY electronics - Abstract
This article is a guest editorial that discusses advancements and future trends in noise radar technology. Noise radar technology uses random and non-periodic radar signals to eliminate ambiguities present in other radars. The article explores the practical aspects of noise radar technology, such as evaluating the degree of randomness in transmission and the computational load of signal processing. It also covers topics like electronic warfare, anti-intercept features, and the potential applications of artificial intelligence in noise radar technology. The article includes specific papers on implementation aspects, waveform selection, anti-intercept features, and artificial intelligence applications in noise radar technology. The authors hope that this special issue provides valuable insights into the advancements and future trends of noise radar technology. [Extracted from the article]
- Published
- 2024
- Full Text
- View/download PDF
22. The Classification Algorithm of Nano Targets Based on Millimeter Wave Radar.
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Zhang, Jing, Zhou, Xiancun, Jia, Chaochuan, Cai, Cuicui, Zhou, Quan, Liu, Yu, Jiang, Qing, and Li, Yajun
- Subjects
- *
MILLIMETER waves , *CLASSIFICATION algorithms , *RADAR targets , *RADAR , *MIMO radar , *SPACE environment - Abstract
Nanodrones are insect-sized drones that could fly in complex environments and confined spaces, and act as an emerging tool for covert surveillance and intelligence attacks, which would become a potential threat to national security. Radar has the advantage of wide range, all-day, and all-weather detection ability, making it a means of detecting such threat. First, this paper introduces a pertinent multiple-input multiple-output (MIMO) millimeter-wave (MMW) radar system, with the advantages of low cost and high accuracy. It is utilized to detect three targets: nanodrone, small helicopter, and mechanical bird, through which more detailed features can be obtained. Then, the echo data of the three targets are processed and analyzed, and their distinct micro-Doppler characteristics were obtained. Finally, the Radar Transformer target classification network is used to classify and identify the targets. It has been confirmed that desired results could be achieved through the above process. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Radar Waveform Selection for Maneuvering Target Tracking in Clutter with PDA-RBPF and Max-Q-Based Criterion.
- Author
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Feng, Xiang, Sun, Ping, Liang, Mingzhi, Wang, Xudong, Zhao, Zhanfeng, and Zhou, Zhiquan
- Subjects
- *
HYBRID systems , *RADAR , *MEASUREMENT errors , *FALSE alarms , *MIMO radar , *AUTONOMOUS vehicles , *BISTATIC radar - Abstract
In this paper, to track maneuvering unmanned surface vehicles (USVs) in scenarios with clutter, we propose a novel method based on the probabilistic data association (PDA) algorithm and Rao-Blackwellized particle filter (RBPF) algorithm, and we further improve the tracking performance by Max-Q criterion-based waveform selection. This work develops a maneuvering target model in the context of clutter, integrating linear and nonlinear states as well as observations with false alarms. In order to jointly tackle the mixed-state tracking problem, the PDA algorithm is integrated into the RBPF framework. This allows it to be used with the complex nonlinear and linear hybrid system and helps to minimize the state dimensions of conventional particle filtering (PF). Additionally, by utilizing Q-learning principles, we provide a Max-Q-based criterion to select the waveform parameters, which guarantees low measurement errors and efficiently handles measurement uncertainties. Our simulation results show that the PDA-RBPF algorithm, which has a more appropriate tracking mechanism, produces results that are more accurate than those of the EKF or PF algorithms alone. Furthermore, the RMSE derived by the Max-Q-based criterion is smaller and more robust than that of other selection methods, as well as yielding a fixed waveform. Our proposed mechanism, which combines the concepts of PDA-RBPF and Max-Q waveform selection, performs well in target tracking tasks and exhibits relatively good performance over some existing ones. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. 3D Pain Face Expression Recognition Using a ML-MIMO Radar Profiler
- Author
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Maria-Jose Lopez, Cesar Palacios-Arias, Jordi Romeu, and Luis Jofre-Roca
- Subjects
3D radar profiler ,contacless ,detection ,facial expressions ,machine learning ,MIMO radar ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This study proposes a new method for the detection of facial expressions of pain using a 3D profiler that combines a multiple-input-multiple-output (MIMO) radar system with a machine learning (ML) model (ML-MIMO radar profiler). It offers a solution for pain detection of facial expressions in a non-invasive, non-intrusive, and cost-effective manner. The ML-MIMO radar profiler employs six radars behind a lens to monitor changes in six facial regions and build a 3D facial profile with real-time facial activity information. A dielectric lens was used to ensure an optimal beam size to effectively illuminate each facial region. Signal processing is performed using dynamic time deformation to determine the longitudinal distance and a discrete stationary wavelet transform to filter the signal and improve accuracy. The information from the 3D profiler was compared with the facial action coding system (FACS) to determine actual facial expressions. A machine learning algorithm was trained to learn action units from the FACS and compare them with the information provided by the ML-MIMO radar profiler, thereby performing facial expression classification. In this study, we analyzed four facial expressions: hapiness, sadness, anger, and pain. Identification and classification were performed using a machine-learning model based on multilayer perceptrons. The results revealed 92% accuracy of the system for pain expression, whereas expressions of happiness, sadness, and anger were detected with 88, 86, and 87% accuracy, respectively.
- Published
- 2024
- Full Text
- View/download PDF
25. 4D radar simulator for human activity recognition.
- Author
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Zhou, Junyu and Le Kernec, Julien
- Subjects
- *
HUMAN activity recognition , *CONTINUOUS wave radar , *MOTION capture (Human mechanics) , *MIMO radar , *RADAR , *SIGNAL processing , *CONGREGATE housing - Abstract
Millimetre‐wave radar has been widely used in health monitoring and human activity recognition owing to its improved range resolution and operation in a variety of environmental conditions. With the MIMO antenna array, 4D radar is increasingly employed in autonomous driving, while its application in assisted living is recent and therefore the value added compared to the increase in signal processing and hardware requirements is still an open question. A model for 4D Time‐division multiplexing (TDM) multiple‐input‐multiple‐output (MIMO) frequency‐modulated Continuous wave radar is established using the human activities from the HDM05 motion capture dataset. The simulator produces an end‐to‐end simulation, including four human motions (jumping Jack, kick, punch, and walk), signal time of flight, noise, MIMO signal processing, and classification. Different pre‐processing and point cloud‐based methods are compared to obtain an average classification accuracy of 90% with PointNet. This study simulates a specific 4D TDM MIMO radar configuration to benchmark signal pre‐processing algorithms, which can also assist other researchers to generate range‐Doppler‐time (range‐Doppler time) point cloud data sets for human activities testing different radar configurations, array configurations, and activities saving valuable time in human resources and hardware development before prototyping to assess expected performances. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Information theoretic waveform design with applications to adaptive‐on‐transmit radar.
- Author
-
Herr, Daniel B., Raju, Pranav S., and Stiles, James M.
- Subjects
- *
MIMO radar , *MEAN square algorithms , *RADAR , *FISHER information - Abstract
The marginal Fisher information (MFI) metric is used to design waveforms for the sake of informationally optimal adaptive‐on‐transmit radar operation. A framework for MFI waveform design is developed and the Polyphase‐Coded FM (PCFM) waveform model is utilised to produce a constant‐modulus, spectrally contained signal amenable to transmission with high‐power amplifiers. The efficacy of the MFI waveform design and minimum mean square error (MMSE) estimation is experimentally demonstrated and extended into an adaptive and dynamic sensing paradigm. The radar transmit waveform is optimised to maximise the Fisher information with respect to the range profile. Upon observing new information from radar echoes, the iterative MMSE (iMMSE) estimator then minimises the estimation error variance according to prior observations. Sequential information maximisation (via waveform design) and error minimisation (via iMMSE) tends towards the Cramér–Rao lower bound (CRLB) with additional measurements improving radar resolution and accuracy. These concepts maximise the information extracted by a radar operating in a congested spectrum where the available bandwidth is limited. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Analysis of Direction Finding Performance of Interferometer for Frequency Division Orthogonal MIMO Radar
- Author
-
Feng Yilun, Jiang Yanwen, Zeng Guilan, Fan Hongqi
- Subjects
mimo radar ,phase modulation ,phase wavefront distortion ,phase interferometer ,direction finding error ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
The spatially synthesized signal pulse of the frequency division orthogonal MIMO radar has the characteristics of time-varying envelope and space-time coupling, which provides a new possibility for actively countering direction finding of the passive electronic reconnaissance system. This paper is dedicated to analyze the direction finding error of the electronic reconnaissance system to the frequency division orthogonal MIMO radar by the phase interferometer direction finding system. Firstly, the MIMO radar synthetic signal model is established for the far-field reconnaissance receiver, and then the influence of the time-varying envelope and phase wavefront distortion characteristics on direction finding performance are analyzed. Moreover, a feasible method based on initial phase modulation is proposed to increase the interferometer’s direction finding error. Simulation results indicate that the dominant regions of DOA estimation errors in interferometers are different due to the influence of phase wavefront distortion and instantaneous signal-to-noise ratio. In addition, the envelope fluctuation characteristics can be manipulated by phase modulation of MIMO radar elements, and the peak to average ratio (PAR) of the synthesized signal can be changed to increase the anti interception performance. In the analysis window of the interferometer, compared with the synthesized signal of phased array radar, when the prior position of the reconnaissance receiver is accurately known, the power of the MIMO radar synthesized signal can be reduced by 25 dB and it can also be reduced by 10 dB when the distance is unknown. Therefore, MIMO radar can increase the direction finding error of the interferometer to a certain degree.
- Published
- 2024
- Full Text
- View/download PDF
28. Magneto‐electric dipole antenna array for 77 GHz automotive radar
- Author
-
Dinuo Bu and Shi‐Wei Qu
- Subjects
antenna radiation patterns ,automotive electronics ,millimetre wave antenna arrays ,MIMO radar ,Telecommunication ,TK5101-6720 ,Electricity and magnetism ,QC501-766 - Abstract
Abstract A 1 × 4 magneto‐electric dipole (ME dipole) antenna array for 77 GHz automotive radar is proposed. The ME dipole is fed by a fork‐shaped microstrip line coupling through a dog‐bone slot. To meet the requirements aimed at automotive radar applications, the beamwidths of the proposed antenna are well‐designed. Specially, a method of adding passive elements on both sides of the array is proposed to increase the 3 dB beamwidth from ±34° to ±52° in azimuth. Additionally, in elevation, a 3 dB beamwidth of ±10° is achieved by designing the spacing between array elements. Moreover, based on low‐loss printed circuit board substrates, radiation efficiency of the proposed array can reach approximately 90% at 77 GHz. Furthermore, a 4 × 4 array is established by arranging four 1 × 4 subarrays spacing 1.95 mm (half a free‐space wavelength at 77 GHz) to study the interactions between subarrays for multiple input multiple output scenarios. A 1 × 4 and a 4 × 4 antenna prototypes are fabricated and measured to validate the correctness of this design. The results show that the proposed antenna is an eligible candidate for the medium‐ and short‐range automotive radars.
- Published
- 2024
- Full Text
- View/download PDF
29. Range and Velocity Resolution of Linear- Frequency-Modulated Signals on Subarray-Mimo Radar
- Author
-
Sabaria Sabaria and Syahfrizal Tahcfulloh
- Subjects
ambiguity-function ,linear-frequency-modulated (lfm) ,mimo radar ,peak sidelobe level ratio ,range and velocity resolution. ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Information technology ,T58.5-58.64 - Abstract
The most important radar system performance is determining the range-velocity of the detected target. This performance is obtained from processing an ambiguity-function (AF) between signals from target reflections and radar radiation signals. Selection of the appropriate waveform transmitted by the radar is a key factor in supporting high resolution radar performance in the AF. There are many waveforms that have been studied in radar systems, especially for multi-antenna radars, i.e., subarray-MIMO (SMIMO) radar which can form phased array (PA) and MIMO radars simultaneously, in the form of linear-frequency-modulated (LFM) signals. In this paper, we examine the use of LFM waveforms combined with SMIMO radar to produce plots of three-dimensional AF as a function of time delay and Doppler shift. The results of the comparison with the Hadamard signal determine the effectiveness of the observed AF performance on parameters such as magnitude, range-velocity resolution, peak sidelobe level ratio, and integrated sidelobe ratio by taking into account the factors of the number of Tx antennas on the PA radar and the number of Tx subarrays on the MIMO radar. The evaluation results of the SMIMO radar configuration (M = 6) with the number of Tx-Rx antenna elements the being 8 provide the best mainlobe magnitude, sidelobe magnitude, range resolution, velocity resolution, PSLR, and ISLR of AF LFM signals compared to conventional radars are 235.2dB, 7.54dB, 37.5m, 75km/s, 29.89dB, and 29.8dB, respectively. Meanwhile, the LFM signal is far superior to the Hadamard signal which has PSLR and ISLR 1.16dB and -3.36dB, respectively.
- Published
- 2024
- Full Text
- View/download PDF
30. MIMO Radar Mainlobe Gain Control Design for Co-Existence With Wireless Communication Systems
- Author
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Omar Aldayel
- Subjects
Beampattern design ,co-existence ,constant modulus ,electronic steering ,main lobe energy constraint ,MIMO radar ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
We tackle the issue of designing a transmit beampattern for multiple-input multiple-output (MIMO) radar while considering its coexistence with wireless communication systems. Our goal is to design a beampattern that can steer the mainlobe and regulate its gain level toward the desired direction. The significant challenge lies in concurrently enforcing the gain constraint along with the constant modulus constraint on the radar waveform. In our work, we propose a novel approach that entails solving a series of constrained quadratic programs to achieve constant modulus at convergence. Additionally, we demonstrate that each problem in the sequence admits a closed-form solution, ensuring analytical tractability. We assess the effectiveness of our proposed Mainlobe and Interference Control (MAIC) algorithm against state-of-the-art MIMO beampattern design techniques, illustrating that MAIC attains the desired gain level while mitigating interference energy in undesired areas.
- Published
- 2024
- Full Text
- View/download PDF
31. RAU-Net-Based Imaging Method for Spatial-Variant Correction and Denoising in Multiple-Input Multiple-Output Radar.
- Author
-
Ren, Jianfei, Luo, Ying, Fan, Changzhou, Feng, Weike, Su, Linghua, and Wang, Huan
- Subjects
- *
MIMO radar , *RADAR , *REAR-screen projection , *IMAGE denoising , *ANTENNA arrays , *COMPUTATIONAL complexity , *SPATIAL variation - Abstract
The conventional back projection (BP) algorithm is an accurate time-domain algorithm widely used for multiple-input multiple-output (MIMO) radar imaging, owing to its independence of antenna array configuration. The time-delay curve correction back projection (TCC-BP) algorithm greatly reduces the computational complexity of BP but suffers from spatial-variant correction, sidelobe interference and background noise due to the use of coherent superposition of echo time-delay curves. In this article, a residual attention U-Net-based (RAU-Net) MIMO radar imaging method that adapts complex noisy scenarios with spatial variation and sidelobe interference is proposed. On the basis of the U-Net underlying structure, we develop the RAU-Net with two modules: a residual unit with identity mapping and a dual attention module to obtain resolution spatial-variant correction and denoising on real-world MIMO radar images. The network realizes MIMO radar imaging based on the TCC-BP algorithm and substantially reduces the total computational time of the BP algorithm on the basis of improving the imaging resolution and denoising capability. Extensive experiments on the simulated and measured data demonstrate that the proposed method outperforms both the traditional methods and learning-imaging methods in terms of spatial-variant correction, denoising and computational complexity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. An antenna subset selection algorithm in distributed MIMO radar for target localization via convolutional neural network
- Author
-
Yingfei Yan, Haihong Tao, and Jia Su
- Subjects
decision making ,MIMO radar ,radar antennas ,Telecommunication ,TK5101-6720 - Abstract
Abstract Since the distributed MIMO radar (DMR) has widely spread transmitters and receivers, it can provide higher target detection probability, as well as superior target tracking and localization performance than the monostatic/bistatic radar systems. An effective radar resource allocation scheme can optimise the DMR system parameter and obtain better system performance. In this paper, a critical but limited system resource is optimised, that is, select a subset of the active radar antennas. In this scenario, the convolutional neural network of the antenna subset selection for target localization (LCNN‐ASS) algorithm in the DMR is proposed based on two free switching policies. The proposed algorithm is immune to the failure of a single policy and selects antenna subsets from the entire sets with a remarkable computational speed. Therefore, the proposed algorithm increases the flexibility of resource scheduling over traditional algorithms. Simulation experiments and performance analysis demonstrate the localization performance and flexibility of the LCNN‐ASS algorithm.
- Published
- 2023
- Full Text
- View/download PDF
33. Waveform design of radar coincidence imaging radiation field based on image entropy
- Author
-
Qian Zhang, Gong Zhang, Ningwei Chen, Qing Xiong, Jun Xie, and Yansen He
- Subjects
MIMO radar ,radar coincidence imaging ,image entropy ,waveform design ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Abstract Radar coincidence imaging (RCI) is a high‐resolution radar imaging mode which constructs a temporal spatial stochastic radiation field (TSSRF) and uses the correlation between reference signal and echoes for imaging. The correlation between the reference matrix and the echoes is the main factor affecting the imaging performance. In fact, radar target characteristics cause fluctuations in the radar cross section and variations in the scattering intensity of each resolution element. The latter degrades the correlation between the reference matrix and the echoes, seriously affecting the image reconstruction. This paper designs the waveform based on image entropy under fixed transmitting and receiving arrays. The targets with fluctuating scattering intensity at each resolution element are statistically modelled. Simulation results show this approach can improve the imaging performance and reduce the energy dissipation degree of the target grid.
- Published
- 2024
- Full Text
- View/download PDF
34. Linear Frequency Modulation and Orthogonal Code Modulation for Co-Located Multiple-Input Multiple-Output High-Frequency Surface Wave Radar.
- Author
-
Kim, Eunhee, Sohn, Sunghwan, Moon, Hyunwook, Choi, Jun Hyeok, and Lee, Kiwon
- Subjects
- *
ORTHOGONAL codes , *MIMO radar , *PULSE frequency modulation , *MODULATION coding , *RADAR - Abstract
A high-frequency surface wave radar (HFSWR) is the only sensor that provides inexpensive surveillance for up to 200 nautical miles (NM) of the exclusive economic zone in the 3–5 MHz band. However, because of its long wavelength, its angular resolution is low. Multiple-input multiple-output (MIMO) technology is an attractive method to improve angular resolution. This paper proposes MIMO waveforms and their processing that can be used in HFSWR systems. This dual modulation method applies linear frequency modulation to each pulse and orthogonal polyphase codes for a few consecutive pulses to enable MIMO processing. The proposed method can effectively remove the correlation of mutual interference and exhibits excellent performance in removing multiple-time-around echoes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. A robust lp‐norm localization of moving targets in distributed multiple‐input multiple‐output radar with measurement outliers
- Author
-
Jing Yang, Chengcheng Liu, Jie Huang, Ting Ding, Dexiu Hu, and Chuang Zhao
- Subjects
MIMO radar ,multistatic radar ,radar signal processing ,Telecommunication ,TK5101-6720 - Abstract
Abstract The Gaussian noise model and estimators based on least squares (LS) are widely used in target localisation with distributed multiple‐input multiple‐output (MIMO) radar because of their computational efficiency. However, the accuracy of existing LS‐based target localisation algorithms deteriorates sharply in the presence of outliers in the measurements. Thus, a robust solution is developed based on the lp‐norm minimisation criterion and iteratively reweighted least squares (IRLS) for locating a moving target with impulse noise using the angle of arrival (AOA), time delay (TD), and Doppler shift (DS) measurements. First, the AOA, TD, and DS measurement noise models are developed based on the α‐stable distribution. Then, the localisation problem is transformed into an lp‐norm minimisation problem by linearising the AOA, TD, and DS measurement equations. Finally, the lp‐norm minimisation problem is solved using an IRLS method to obtain the target position and estimate the velocity. Moreover, the optimum of the norm order (p) and the Cramér–Rao lower bound for the target position and velocity estimation are derived under α‐stable distributed measurement noise. The simulation results demonstrate that the developed algorithm offers higher accurascy and robustness than the existing ones in the presence of measurement outliers.
- Published
- 2023
- Full Text
- View/download PDF
36. A GPU‐based real‐time processing system for frequency division multiple‐input‐multiple‐output radar
- Author
-
Gaogao Liu, Yuqian Bao, Ning Yue, Sitian Wang, Hui Wu, Qiang Liu, and Wenbo Yang
- Subjects
array signal processing ,frequency‐domain analysis ,MIMO radar ,optimisation ,parallel algorithms ,Telecommunication ,TK5101-6720 - Abstract
Abstract Multiple‐Input‐Multiple‐Output (MIMO) radar has the characteristic of multiple antenna channels, bringing on a big data volume for signal processing. Therefore, the trade‐off between detection ability and computational efficiency is always considered. In this article, an optimisation system is proposed to enhance the real‐time performance of frequency division MIMO radar without compromising accuracy. For the scenario of low‐altitude small target detection, a signal processing acceleration method is proposed and a MIMO radar optimisation system based on graphics processing unit (GPU) architecture is built. The signal model of frequency division MIMO radar is first established, improving the classical signal processing flow efficiency from the perspective of reducing fast Fourier transform (FFT) times and windowing operation times. To achieve an advanced acceleration, the parallel architecture of ArrayFire‐library in GPU is then employed. Distinct minimum parallel units are extracted by analysing the principle of digital beamforming (DBF), pulse compression, moving target detection (MTD), and constant false‐alarm rate (CFAR) algorithms. And the corresponding parallel algorithms are designed to constitute a parallel acceleration system of frequency division MIMO. Simulation results indicate that the proposed method significantly improves the efficiency of MIMO system with a maximum acceleration ratio of 65 times, meeting the real‐time processing requirements.
- Published
- 2023
- Full Text
- View/download PDF
37. Optimal Design of Group Orthogonal Phase-Coded Waveforms for MIMO Radar.
- Author
-
Liu, Tianqu, Sun, Jinping, Wang, Guohua, Yao, Xianxun, and Qiao, Yaqiong
- Subjects
- *
MIMO radar , *RADAR interference , *ORTHOGONALIZATION , *RADIO frequency - Abstract
Digital radio frequency memory (DRFM) has emerged as an advanced technique to achieve a range of jamming signals, due to its capability to intercept waveforms within a short time. multiple-input multiple-output (MIMO) radars can transmit agile orthogonal waveform sets for different pulses to combat DRFM-based jamming, where any two groups of waveform sets are also orthogonal. In this article, a group orthogonal waveform optimal design model is formulated in order to combat DRFM-based jamming by flexibly designing waveforms for MIMO radars. Aiming at balancing the intra- and intergroup orthogonal performances, the objective function is defined as the weighted sum of the intra- and intergroup orthogonal performance metrics. To solve the formulated model, in this article, a group orthogonal waveform design algorithm is proposed. Based on a primal-dual-type method and proper relaxations, the proposed algorithm transforms the original problem into a series of simple subproblems. Numerical results demonstrate that the obtained group orthogonal waveforms have the ability to flexibly suppress DRFM-based deceptive jamming, which is not achievable using p-majorization–minimization (p-MM) and primal-dual, two of the most advanced orthogonal waveform design algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Generalised two‐level nested multiple‐input multiple‐output radar direction of arrival estimation with high degrees of freedom and low mutual coupling
- Author
-
Cong Qin, Qin Zhang, Guimei Zheng, Yule Zhang, and Shiqiang Wang
- Subjects
array signal processing ,direction‐of‐arrival estimation ,MIMO radar ,Telecommunication ,TK5101-6720 - Abstract
Abstract To address the problems of traditional two‐level nested arrays (TTNA) with low degrees of freedom and high mutual coupling, a generalised two‐level nested MIMO radar array with high degrees of freedom and low mutual coupling for the direction of arrival (DOA) estimation is proposed. First, two coprime expansion factors are introduced in the TTNA to mitigate mutual coupling among array elements and enhance its degrees of freedom. Secondly, the range of consecutive lags and the total number of virtual array elements are derived in closed form under the structures of ‘sum–difference co‐array’. Finally, utilising the atomic norm minimisation theory, the authors address the issue of discrete holes caused by different coprime expansion factors through filling in virtual arrays at discontinuities. Furthermore, a convex optimisation model to recover equivalent received signals from these filled virtual arrays is established, which is combined with a multiple signal classification algorithm for DOA estimation. Simulation results validate the rationality of the array structure and demonstrate the effectiveness of the algorithm.
- Published
- 2023
- Full Text
- View/download PDF
39. A Feasibility Study of Nearshore Bathymetry Estimation via Short-Range K-Band MIMO Radar.
- Author
-
Ludeno, Giovanni, Antuono, Matteo, Soldovieri, Francesco, and Gennarelli, Gianluca
- Subjects
- *
MIMO radar , *REMOTE sensing by radar , *OCEAN waves , *SURVEILLANCE radar , *BATHYMETRIC maps , *BATHYMETRY , *DISPERSION relations - Abstract
This paper provides an assessment of a 24 GHz multiple-input multiple-output radar as a remote sensing tool to retrieve bathymetric maps in coastal areas. The reconstruction procedure considered here exploits the dispersion relation and has been previously employed to elaborate the data acquired via X-band marine radar. The estimation capabilities of the sensor are investigated firstly on synthetic radar data. With this aim, case studies referring to sea waves interacting with a constant and a spatially varying bathymetry are both considered. Finally, the reconstruction procedure is tested by processing real data recorded at Bagnoli Bay, Naples, South Italy. The preliminary results shown here confirm the potential of the radar sensor as a tool for sea wave monitoring. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Design of multiple‐input multiple‐output radar amplitude‐bounded waveforms with desired ambiguity function based on sequential quadratic programming.
- Author
-
Wei, Wenyan, Wei, Yinsheng, and Yu, Lei
- Subjects
- *
MIMO radar , *QUADRATIC programming , *CONJUGATE gradient methods , *RADAR antennas , *AMBIGUITY , *RADAR , *FUNCTIONS of bounded variation - Abstract
The transmit waveform with ambiguity function specifications in the range‐Doppler plane has been of great interest in traditional single antenna radar systems in recent years. This paper considers the design of waveform sets with a desired slow‐time ambiguity function for multiple‐input multiple‐output radar. Specifically, it is desirable that the ambiguity function has low sidelobes where clutter occurs, as this reduces the impact of the clutter on target detection. Instead of unimodular waveforms, the authors consider amplitude modulation signals and introduce the bound constraint on signal amplitudes into the optimisation for the consideration of transmitter efficiency. The design problem is formulated as minimising the weighted integrated sidelobes level of the ambiguity function over the range‐Doppler plane under bound constraints. The resulting problem has a highly non‐linear objective function and is constrained by bound constraints and quadratic equality (constant energy) constraints, making it difficult to solve. The authors develop an efficient algorithm based on the sequential quadratic programming technique and non‐linear conjugate gradient method to solve it. Simulation results show that the proposed algorithm is superior to the existing methods. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Detection and Estimation of Coordinates of Small Sized Ground Objects MIMO Radar with Wavelet Signal Processing.
- Author
-
Basha, Syed Asif, Sujatha, S., Subhashini, P., Chitra, R. Jothi, Navaneethakrishnan, S., and Rajanandhini, C.
- Subjects
- *
MIMO radar , *RADAR signal processing , *GROUND penetrating radar , *SIGNAL-to-noise ratio - Abstract
A study was carried out on algorithms for detecting small-sized ground objects (LSGs) using Haar and Daubechies wavelet filtering. The dependences of the probability of correct detection on the signal-to-noise ratio in the MIMO 2x2 and MIMO 4x4 channels were obtained using Haar and Daubechies wavelet filters at different UAV speeds. A study of algorithms for estimating errors in the angular position of the INR using Haar and Daubechies wavelet filters was carried out. The dependences of estimates of errors of the angular position of the INO on the signal-to-noise ratio at UAV speeds of 20, 40 and 100 m/s for MIMO 2x2 and MIMO 4x4 were obtained. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Joint Antenna Scheduling and Power Allocation for Multi-Target Tracking under Range Deception Jamming in Distributed MIMO Radar System
- Author
-
Zhengjie Li, Yang Yang, Ruijun Wang, Cheng Qi, and Jieyu Huang
- Subjects
resource scheduling ,range deception jamming ,MIMO radar ,multi-target tracking ,PC-CRLB ,Science - Abstract
The proliferation of electronic countermeasure (ECM) technology has presented military radar with unprecedented challenges as it remains the primary method of battlefield situational awareness. In this paper, a joint antenna scheduling and power allocation (JASPA) scheme is put forward for multi-target tracking (MTT) in the distributed multiple-input multiple-output (D-MIMO) radar. Aiming at radar resource scheduling in the presence of range deception jamming (RDJ), the false target discriminator is designed based on the Cramer–Rao lower bound (CRLB) in terms of the spoofing range, and the predicted conditional CRLB (PC-CRLB) plays a role in evaluating tracking accuracy. The JASPA scheme integrates the quality of service (QoS) principle to develop an optimization model based on false target discrimination, with the objective of enhancing both the discrimination probability of false targets and the tracking accuracy of real targets concurrently. Since the optimal variables can be separated in constraints, a four-step optimization cycle (FSOC)-based algorithm is developed to solve the multidimensional non-convex problem. Numerical simulation results are provided to illustrate the effectiveness of the proposed JASPA scheme in dealing with MTT in the RDJ environment.
- Published
- 2024
- Full Text
- View/download PDF
43. Spatial–Temporal Joint Design and Optimization of Phase-Coded Waveform for MIMO Radar
- Author
-
Wei Lei, Yue Zhang, Zengping Chen, Xiaolong Chen, and Qiang Song
- Subjects
MIMO radar ,waveform design ,spatial–temporal joint optimization ,beam-pattern matching ,L2p-Norm ,spatial synthesis signals ,Science - Abstract
By simultaneously transmitting multiple different waveform signals, a multiple-input multiple-output (MIMO) radar possesses higher degrees of freedom and potential in many aspects compared to a traditional phased-array radar. The spatial–temporal characteristics of waveforms are the key to determining their performance. In this paper, a transmitting waveform design method based on spatial–temporal joint (STJ) optimization for a MIMO radar is proposed, where waveforms are designed not only for beam-pattern matching (BPM) but also for minimizing the autocorrelation sidelobes (ACSLs) of the spatial synthesis signals (SSSs) in the directions of interest. Firstly, the STJ model is established, where the two-step strategy and least squares method are utilized for BPM, and the L2p-Norm of the ACSL is constructed as the criterion for temporal characteristics optimization. Secondly, by transforming it into an unconstrained optimization problem about the waveform phase and using the gradient descent (GD) algorithm, the hard, non-convex, high-dimensional, nonlinear optimization problem is solved efficiently. Finally, the method’s effectiveness is verified through numerical simulation. The results show that our method is suitable for both orthogonal and partial-correlation MIMO waveform designs and efficiently achieves better spatial–temporal characteristic performances simultaneously in comparison with existing methods.
- Published
- 2024
- Full Text
- View/download PDF
44. A Novel, Efficient Algorithm for Subsurface Radar Imaging below a Non-Planar Surface.
- Author
-
Ullmann, Ingrid and Vossiek, Martin
- Subjects
- *
RAY tracing algorithms , *GROUND penetrating radar , *SYNTHETIC aperture radar , *REMOTE sensing , *NONDESTRUCTIVE testing , *IMAGE reconstruction , *ELECTROMAGNETIC waves - Abstract
In classical radar imaging, such as in Earth remote sensing, electromagnetic waves are usually assumed to propagate in free space. However, in numerous applications, such as ground penetrating radar or non-destructive testing, this assumption no longer holds. When there is a multi-material background, the subsurface image reconstruction becomes considerably more complex. Imaging can be performed in the spatial domain or, equivalently, in the wavenumber domain (k-space). In subsurface imaging, to date, objects with a non-planar surface are commonly reconstructed in the spatial domain, by the Backprojection algorithm combined with ray tracing, which is computationally demanding. On the other hand, objects with a planar surface can be reconstructed more efficiently in k-space. However, many non-planar surfaces are partly planar. Therefore, in this paper, a novel concept is introduced that makes use of the efficient k-space-based reconstruction algorithms for partly planar scenarios, too. The proposed algorithm forms an image from superposing sub-images where as many image parts as possible are reconstructed in the wavenumber domain, and only as many as necessary are reconstructed in the spatial domain. For this, a segmentation scheme is developed to determine which parts of the image volume can be reconstructed in the wavenumber domain. The novel concept is verified by measurements, both from monostatic synthetic aperture radar data and multiple-input–multiple-output radar data. It is shown that the computational efficiency for imaging irregularly shaped geometries can be significantly augmented when applying the proposed concept. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
45. A robust lp‐norm localization of moving targets in distributed multiple‐input multiple‐output radar with measurement outliers.
- Author
-
Yang, Jing, Liu, Chengcheng, Huang, Jie, Ding, Ting, Hu, Dexiu, and Zhao, Chuang
- Subjects
- *
LOCALIZATION (Mathematics) , *RADAR , *BURST noise , *DOPPLER effect , *RADAR signal processing , *RANDOM noise theory , *DISTRIBUTED algorithms - Abstract
The Gaussian noise model and estimators based on least squares (LS) are widely used in target localisation with distributed multiple‐input multiple‐output (MIMO) radar because of their computational efficiency. However, the accuracy of existing LS‐based target localisation algorithms deteriorates sharply in the presence of outliers in the measurements. Thus, a robust solution is developed based on the lp ${l}_{p}$‐norm minimisation criterion and iteratively reweighted least squares (IRLS) for locating a moving target with impulse noise using the angle of arrival (AOA), time delay (TD), and Doppler shift (DS) measurements. First, the AOA, TD, and DS measurement noise models are developed based on the α‐stable distribution. Then, the localisation problem is transformed into an lp ${l}_{p}$‐norm minimisation problem by linearising the AOA, TD, and DS measurement equations. Finally, the lp ${l}_{p}$‐norm minimisation problem is solved using an IRLS method to obtain the target position and estimate the velocity. Moreover, the optimum of the norm order (p) and the Cramér–Rao lower bound for the target position and velocity estimation are derived under α‐stable distributed measurement noise. The simulation results demonstrate that the developed algorithm offers higher accurascy and robustness than the existing ones in the presence of measurement outliers. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. An antenna subset selection algorithm in distributed MIMO radar for target localization via convolutional neural network.
- Author
-
Yan, Yingfei, Tao, Haihong, and Su, Jia
- Subjects
- *
CONVOLUTIONAL neural networks , *BISTATIC radar , *MIMO radar , *RADAR targets , *SUBSET selection , *ANTENNAS (Electronics) , *DISTRIBUTED algorithms - Abstract
Since the distributed MIMO radar (DMR) has widely spread transmitters and receivers, it can provide higher target detection probability, as well as superior target tracking and localization performance than the monostatic/bistatic radar systems. An effective radar resource allocation scheme can optimise the DMR system parameter and obtain better system performance. In this paper, a critical but limited system resource is optimised, that is, select a subset of the active radar antennas. In this scenario, the convolutional neural network of the antenna subset selection for target localization (LCNN‐ASS) algorithm in the DMR is proposed based on two free switching policies. The proposed algorithm is immune to the failure of a single policy and selects antenna subsets from the entire sets with a remarkable computational speed. Therefore, the proposed algorithm increases the flexibility of resource scheduling over traditional algorithms. Simulation experiments and performance analysis demonstrate the localization performance and flexibility of the LCNN‐ASS algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
47. Joint antenna selection and beamforming for frequency diverse multiple‐input multiple‐output radar in mainlobe spectrum interferences and signal‐dependent interferences coexistence scenarios.
- Author
-
Shao, Xiaolang, Hu, Taiyang, Zhang, Jinyu, and Xiao, Zelong
- Subjects
- *
MIMO radar , *ANTENNAS (Electronics) , *PHASED array antennas , *BEAMFORMING , *RADAR , *ADAPTIVE signal processing - Abstract
Due to the controllable degrees of freedom of frequency diverse array in the distance dimension, the frequency diverse multiple‐input multiple‐output (FDA‐MIMO) radar can easily deal with mainlobe interference, which is often difficult to solve in traditional phased arrays. Nevertheless, the performance of FDA‐MIMO radar will suffer from degradation in the scenario where spectrum interferences and signal‐dependent interferences coexist. In order to solve this problem, a novel FDA‐MIMO radar framework via antenna switching is proposed. Based on this framework, an effective method for jointly optimising antenna selection and beamforming against spectrum interferences and signal‐dependent interferences is developed. The resulting optimization problem is nonconvex and NP‐hard owing to the integer constraints caused by antenna selection. By relaxing the integer constraints, the original problem can be transformed into a convex optimization form and an iterative reweighting strategy is used to force the obtained solution to satisfy the integer constraints. Simulation examples show that the proposed algorithm has better performance in output signal‐to‐interference‐plus‐noise ratio (SINR) and beampattern radiation performance than the existing competitive methods. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Boosting multi‐target recognition performance with multi‐input multi‐output radar‐based angular subspace projection and multi‐view deep neural network
- Author
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Emre Kurtoğlu, Sabyasachi Biswas, Ali C. Gurbuz, and Sevgi Zubeyde Gurbuz
- Subjects
Deep Learning ,Human Activity Recognition ,MIMO Radar ,Telecommunication ,TK5101-6720 - Abstract
Abstract Current radio frequency (RF) classification techniques assume only one target in the field of view. Multi‐target recognition is challenging because conventional radar signal processing results in the superposition of target micro‐Doppler signatures, making it difficult to recognise multi‐target activity. This study proposes an angular subspace projection technique that generates multiple radar data cubes (RDC) conditioned on angle (RDC‐ω). This approach enables signal separation in the raw RDC, making possible the utilisation of deep neural networks taking the raw RF data as input or any other data representation in multi‐target scenarios. When targets are in closer proximity and cannot be separated by classical techniques, the proposed approach boosts the relative signal‐to‐noise ratio between targets, resulting in multi‐view spectrograms that boosts the classification accuracy when input to the proposed multi‐view DNN. Our results qualitatively and quantitatively characterise the similarity of multi‐view signatures to those acquired in a single‐target configuration. For a nine‐class activity recognition problem, 97.8% accuracy in a 3‐person scenario is achieved, while utilising DNN trained on single‐target data. We also present the results for two cases of close proximity (sign language recognition and side‐by‐side activities), where the proposed approach has boosted the performance.
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- 2023
- Full Text
- View/download PDF
49. Cognitive Radar Waveform Design Method under the Joint Constraints of Transmit Energy and Spectrum Bandwidth.
- Author
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Yang, Chen, Yang, Wei, Qiu, Xiangfeng, Zhang, Wenpeng, Lu, Zhejun, and Jiang, Weidong
- Subjects
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RADAR , *BANDWIDTHS , *MIMO radar , *CLOSED loop systems , *SYSTEMS design , *FREQUENCY spectra , *COGNITIVE radio - Abstract
The water-filling (WF) algorithm is a widely used design strategy in the radar waveform design field to maximize the signal-to-interference-plus-noise ratio (SINR). To address the problem of the poor resolution performance of the waveform caused by the inability to effectively control the bandwidth, a novel waveform-related optimization model is established in this paper. Specifically, a corrected SINR expression is first derived to construct the objective function in our optimization model. Then, equivalent bandwidth and energy constraints are imposed on the waveform to formulate the waveform-related non-convex optimization model. Next, the optimal frequency spectrum is obtained using the Karush–Kuhn–Tucker condition of our non-convex model. Finally, the transmit waveform in the time domain is synthesized under the constant modulus constraint. Different experiments based on simulated and real-measured data are constructed to demonstrate the superior performance of the designed waveform on the SINR and equivalent bandwidth compared to the linear frequency modulated signal and waveform designed by the WF algorithm. In addition, to further evaluate the effectiveness of the proposed algorithm in the application of cognitive radar (CR), a closed-loop radar system design strategy is introduced based on our waveform design method. The experiments under real-measured data confirm the advantages of CR compared to the traditional open-loop radar structure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
50. Development of modular and robust high power solid-state transmit-receive module for Gadanki Ionospheric Radar Interferometer.
- Author
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Rao, Durga and Rao, Srinivasa
- Subjects
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PHASED array antennas , *RADAR , *GLOBAL Positioning System , *IONOSPHERIC plasma , *ANTENNAS (Electronics) , *BEAM steering , *MIMO radar , *ARTIFICIAL satellite tracking - Abstract
The study of ionospheric effects1 on the satellite-based communication signals has been a continued topic of interest both for academic interest and global positioning system aided navigation applications. These communication signals are affected by the fieldaligned irregularities, suffers from fading and range spreading when they pass through the ionosphere.2 To study the low latitude ionospheric plasma irregularities, dedicated radar with wide beam steering capabilities is required. Recently Gadanki Ionospheric Radar Interferometer, which operates at 30 MHz frequency, has been realized at National Atmospheric Research Laboratory, Gadanki, to scan a larger part of the sky up to -50°C in East-West direction. The radar system employs a 160 element phased antenna array, antenna system, state-of-the-art 8 kW high power solid-state transmit-receive modules, and direct digital receiver. In order to carryout round-the-clock scientific observations, highly reliable, robust designs are required to realize the high power transmit-receive modules. Detailed design philosophies are described with modular concept and better thermal designs in this paper to achieve the high power requirements. Performance results of the transmit-receive module and the sample scientific results obtained by employing these transmit-receive modules are presented in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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