- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Adaptive Sidelobe Cancellation Technique for Atmospheric Radars Containing Arrays with Nonuniform Gain
摘要： The design and performance evaluation is presented of a partially adaptive array that suppresses clutter from low elevation angles in atmospheric radar observations. The norm-constrained and directionally constrained minimization of power (NC-DCMP) algorithm has been widely used to suppress clutter in atmospheric radars, because it can limit the signal-to-noise ratio (SNR) loss to a designated amount, which is the most important design factor for atmospheric radars. To suppress clutter from low elevation angles, adding supplemental antennas that have high response to the incoming directions of clutter has been considered to be more efficient than to divide uniformly the high-gain main array. However, the proper handling of the gain differences of main and sub-arrays has not been well studied. We performed numerical simulations to show that using the proper gain weighting, the sub-array configuration has better clutter suppression capability per unit SNR loss than the uniformly divided arrays of the same size. The method developed is also applied to an actual observation dataset from the MU radar at Shigaraki, Japan. The properly gain-weighted NC-DCMP algorithm suppresses the ground clutter sufficiently with an average SNR loss of about 1 dB less than that of the uniform-gain configuration.
关键词： robust adaptive beamforming,clutter suppression,atmospheric radars,partial adaptivity
更新于2025-09-23 15:23:52
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Interference Suppression of Partially Overlapped Signals Using GSVD and Orthogonal Projection
摘要： In order to solve the problem in Automatic Identification System (AIS) that the signal in the target slot cannot be correctly received due to partial overlap of signals in adjacent time slots, the paper introduces a new criterion: maximum expected signal power (MESP) and proposes a novel beamforming algorithm based on generalized singular value decomposition (GSVD) and orthogonal projection. The algorithm employs GSVD to estimate the signal subspace, and adopts orthogonal projection to project the received signal onto the orthogonal subspace of the non-target signal. Then, beamforming technique is used to maximize the output power of the target signal on the basis of MESP. Theoretical analysis and simulation results show the effectiveness of the proposed algorithm.
关键词： blind beamforming,automatic identification system,partial overlapping,generalized singular value decomposition,orthogonal projection
更新于2025-09-23 15:23:52
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Unsupervised Learning Based Fast Beamforming Design for Downlink MIMO
摘要： In the downlink transmission scenario, power allocation and beamforming design at the transmitter are essential when using multiple antenna arrays. This paper considers a multiple input-multiple output broadcast channel to maximize the weighted sum-rate under the total power constraint. The classical weighted minimum mean-square error (WMMSE) algorithm can obtain suboptimal solutions but involves high computational complexity. To reduce this complexity, we propose a fast beamforming design method using unsupervised learning, which trains the deep neural network (DNN) offline and provides real-time service online only with simple neural network operations. The training process is based on an end-to-end method without labeled samples avoiding the complicated process of obtaining labels. Moreover, we use the 'APoZ'-based pruning algorithm to compress the network volume, which further reduces the computational complexity and volume of the DNN, making it more suitable for low computation-capacity devices. Finally, experimental results demonstrate that the proposed method improves computational speed significantly with performance close to the WMMSE algorithm.
关键词： beamforming,unsupervised learning,deep learning,network pruning,MIMO
更新于2025-09-23 15:23:52
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A Simple Channel Independent Beamforming Scheme with Parallel Uniform Circular Array
摘要： In this letter, we consider a uniform circular array (UCA) based line-of-sight (LOS) multiple-input-multiple-output (MIMO) system, where the transmit and receive UCAs are parallel but non-coaxial with each other. We propose a simple channel independent beamforming scheme with fast symbol-wise maximum likelihood (ML) detection.
关键词： multiple-input-multiple-output (MIMO),channel independent beamforming,Uniform circular array (UCA),fast maximum likelihood (ML)
更新于2025-09-23 15:22:29
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[IEEE 2018 OCEANS - MTS/IEEE Kobe Techno-Ocean (OTO) - Kobe, Japan (2018.5.28-2018.5.31)] 2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO) - The 3D Imaging for Underwater Objects Using SAS Processing Based on Sparse Planar Array
摘要： Acoustic imaging of underwater objects has to include targets of two kinds which are unburied and buried, so that it can demonstrate the underwater environment thoroughly. Especially for the buried objects, it is much more difficult than unburied ones to obtain a qualified acoustical image due to the high backscattering reverberation generated by buried sediments. The three-dimensional downward-looking synthetic aperture sonar(SAS) imaging algorithm based on T-type sparse planar array is presented here to quantify and enhance the performance of underwater objects imaging and to improve the efficiency of sonar mapping as well. Pulse compression, multi narrow-beam nearfield beamforming and synthetic aperture method are applied in vertical direction, across-track direction and along-track direction, respectively. The simulation results show that with regard to the along-track direction, resolution is dependent on the length of the physical aperture and central frequency, as well as irrelevant to the range. Meanwhile, the signal-to-noise ratio(SNR) of image improves with the increase of the length of the synthetic aperture. The across-track direction resolution, however, degrades with the increase of the number of the along-track array elements. Moreover, the method is applied to the sea-trial data of shallow seawater area, where the depth of water is approximately 100 meters and the linear objects are buried at depth of about 3 meters. The results show that the presented algorithm is capable of leading the qualified imaging results for underwater targets.
关键词： underwater object imaging,downward-looking mode,nearfield beamforming,synthetic aperture processing
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Single-Snapshot Adaptive Beamforming
摘要： Adaptive beamformers are sensitive to model mismatch, especially when the number of training samples is small or the training samples are contaminated by the signal component. In this paper, we consider an extreme scenario where only a single signal-contaminated snapshot is available for adaptive beamformer design. In such a case, we cannot perform direct inversion or eigen-decomposition of the rank-one sample covariance matrix required in adaptive beamformer design. To address this issue, we formulate a sparsity-constrained covariance matrix fitting problem to estimate the spatial spectrum distribution over the observed spatial domain, which is then used for adaptive beamformer design via the sparse reconstruction of the interference-plus-noise covariance matrix. Simulation results demonstrate the performance advantage of the proposed adaptive beamforming algorithm over other beamforming algorithms suitable for the single-snapshot scenario.
关键词： single snapshot,sparsity,covariance matrix reconstruction,Adaptive beamforming,covariance matrix fitting
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - An Alternating Minimization Approach to Optimizing Subarray Configuration for a Large Phased Array
摘要： A large size phased array is a powerful system for surveillance, but must be appropriately decomposed as subarrays for efficient digital beamforming. One fundamental question is how to configure a large array as subarrays to satisfy various signal processing requirements. This work deals with two basic signal processing tasks, synthesizing multiple beams at subarray level and adaptively suppressing multiple interferences. Two optimization criteria to jointly design subarray configuration and digital weights for subarrays are proposed. To handle the large number of variables in the optimization formulations, we propose an alternating minimization approach with low computation cost. Numerical simulations are presented to demonstrate the effectiveness of the proposed algorithm.
关键词： beamforming,Phased array,alternating optimization,subarray
更新于2025-09-23 15:22:29
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Simultaneous Axial Multifocal Imaging using a Single Acoustical Transmission: a Practical Implementation
摘要： Standard ultrasound imaging techniques rely on sweeping a focused beam across a field of view; however, outside the transmission focal depth, image resolution and contrast are degraded. High-quality deep tissue in vivo imaging requires focusing the emitted field at multiple depths, yielding high resolution and high contrast ultrasound images but at the expense of a loss in frame rate. Recent developments in ultrasound technologies have led to user-programmable systems, which enable real-time dynamic control over the phase and apodization of each individual element in the imaging array. In this paper, we present a practical implementation of a method to achieve simultaneous axial multifoci using a single acoustical transmission. Our practical approach relies on the superposition of axial multifoci waveforms in a single transmission. The delay in transmission between different elements is set such that pulses constructively interfere at multiple focal depths. The proposed method achieves lateral resolution similar to successive focusing, but with an enhanced frame rate. The proposed method uses standard dynamic receive beamforming, identical to two-way focusing, and does not require additional post-processing. Thus, the method can be implemented in real-time on programmable ultrasound systems that allow different excitation signals for each element. The proposed method is described analytically and validated by laboratory experiments in phantoms and ex vivo biological samples.
关键词： beamforming,frame rate,multifoci,ultrasound imaging
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Feasibility Study of a Coherent Multi-Transducer US Imaging System
摘要： Ultrasound images can be difficult to assess, because of the limited resolution and view-dependent artefacts that are inherent to the small aperture transducers used clinically. An extended aperture has the potential to greatly improve imaging performance. This work introduces a fully coherent multi-transducer ultrasound imaging system, formed by two ultrasound transducers that are synchronized, freely located in space with a common field of view and transmit plane waves. Through coherent combination of the different transducers, a larger effective aperture is obtained and then an improved final image. First phantom images produced using this technique are presented here.
关键词： Large Aperture,Beamforming,Image Resolution,Plane Waves,Ultrasound Imaging
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Investigations on the Reconstruction of Multistatic Large Along-Track SAR Constellations for HRWS Imaging
摘要： This paper presents first the performance analysis of the state-of-the-art multi-channel SAR signal reconstruction algorithms that suffer from the geometrical approximations. Then, it proposes a two-step signal reconstruction method for spaceborne large along-track baseline multistatic SAR constellations operated with a pulse repetition frequency (PRF) under the Nyquist rate. The suggested algorithm first applies a bulk polychromatic reconstruction in wavenumber domain and then compensates the residual range variance in range-Doppler domain. This simple modification helps to reduce overall phase errors in the reconstruction process of the analysed case with respect to the state-of-the-art algorithms by about one order of magnitude. The performance of the algorithm is verified by showing the results in point target simulations for a multistatic X-band constellation with a resolution of about 15 times the carrier wavelength.
关键词： high-resolution wide-swath (HRWS) radar,multistatic radar signal processing,Digital beamforming
更新于2025-09-23 15:22:29