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In this paper, we consider the design of optimum sparse adaptive beamformer with controlled quiescent beampattern for multiple sources in interference-free environment. The two measures of the maximum output signal-to-noise ratio (SNR) and approximately equal gains towards all sources incident on the array are applied for optimality. We combine both adaptive and deterministic approaches to sparse...
Falls are the major cause of accidents in the elderly population. Propelled by their non-intrusive sensing capabilities and robustness to heat and lighting conditions, radar-based automated fall detection systems have emerged as a candidate technology for reliable fall detection in assisted living. The use of a multiple radar system, in lieu of a single radar unit, for indoor monitoring combats occlusion...
Radar technology for in-home gait assessment has recently become of increased interest due to its safety, reliability and privacy-preserving, non-wearable sensing mode. Radar-based micro-Doppler signatures of humans can be used to reveal key characteristics that capture changes in gait and enable detecting abnormalities. In elderly care, the influence of assistive walking devices on gait time-frequency...
We employ a near-field coherence factor for rough surface clutter mitigation in forward-looking ground penetrating radar imagery. The coherence factor is first used to generate a “coherence map” of the region of interest (ROI). Then, a pixel-by-pixel multiplication of a tomographic image of the ROI with the coherence map is performed to generate an enhanced image. Electromagnetic modeled data of shallow...
In this paper, we consider robust direction-of-arrival (DOA) estimation for an array that contains mis-calibrated sensors with unknown gain and phase uncertainties. We develop two robust DOA estimation algorithms based on the maximum correntropy criterion (MCC). In the first algorithm, adaptively optimized weighting factors are obtained and applied to each sensor to effectively mitigate the effect...
In this paper, we consider optimum array configurations for multiple satellite signals in interference-free environment. The two measures of maximum output signal-to-noise ratio (SNR) and equal gains towards all sources incident on the array are considered for the array design. As it is computationally exhaustive to enumerate all configurations and implement eigenvalue decomposition to compare respective...
Radar for indoor monitoring has recently attracted much attention that is driven by its safety, privacy-preserving, and non-wearable sensing mode. Micro-Doppler signatures offered by radars operating in the K-band can disclose intricate details and characteristics of human gait. This paper reveals key Doppler features associated with human legs in gait motions which have been overlooked or ignored...
Radar-based automated fall detection systems are considered as an important and emerging technology for elderly assisted living. These radar systems provide non-intrusive sensing capabilities to detect fall events. Various studies have used micro-Doppler signatures to determine falls. However, Doppler radar fall detection systems suffer false alarms stemming from other sudden non-rhythmic motion articulations...
In this paper, we develop a new technique for information embedding into the emission of multiple-input multiple-output (MIMO) radar using dual-functionality platforms. A set of orthogonal waveforms occupying the same band is used to implement the primary MIMO radar operation. The secondary communication function is implemented by embedding one phase-shift keying (PSK) communication symbol in each...
Feature selection based on combined Doppler and range information improves fall detection and enables better discrimination against similar high Doppler non-rhythmic motions, such as sitting. A fall is typically characterized by an extension in range beyond that associated with sitting, which is determined by the seat horizontal depth. In this paper, we demonstrate, using time-frequency (TF) spectrograms,...
A conventional coprime array is a linear array, which consists of two uniform linear subarrays to construct an effective difference coarray with certain desirable characteristics. In this paper, we propose a parallel coprime array structure and a novel algorithm for two-dimensional (2-D) direction-of-arrival (DOA) estimation. By vectorizing the cross-covariance matrix of subarray data, the resulting...
Fall-related injuries can have a significant impact on the quality of life of the elderly population. Because of the upward trend in the elderly for continued independent living, there is a growing need for reliable fall detectors that can enable prompt assistance in case of falls. Doppler radar technology offers a number of desirable attributes for realization of fall detection and health monitoring...
Dual-functionality platforms have recently been proposed to jointly and simultaneously enable radar target illumination and establish wireless communication links. This duality serves as means to alleviate the spectrum congestion crisis. In this paper, we consider the problem of radar system design for dual-function radar-communications (DFRC). We develop a new transmit signaling scheme which permits...
The effect of mutual coupling on the direction-of-arrival (DOA) estimation using sparse arrays of dipole antennas is investigated. The open circuit method is used to model the mutual coupling. DOA estimation performance in the presence of mutual coupling is compared and contrasted for different array configurations, namely, uniform linear arrays, minimum redundancy arrays, nested arrays, and co-prime...
We propose fast direction-of-arrival (DOA) estimation of multiple sources using a single snapshot. This problem arises in many practical applications and is pertinent to automotive radar. Existing beamforming algorithms incur a high computational cost as they usually require significant zero-padding or fail to fully remove the bias that results from the spectral leakage, especially at high signal...
Recently, dual-function radar-communication systems in which the radar platform and resources are used for communication signal embedding have emerged as means to alleviate spectrum congestion and ease competition over frequency bandwidth. In this paper, we introduce a new technique for information embedding specific to multiple-input multiple output (MIMO) radar. We exploit the fact that in a MIMO...
Sparsity-aware multi-sensor multi-target tracking (MTT) algorithms comprise a two-step sequential architecture that cascades a group sparse reconstruction scheme and a multi-target tracker. The former exploits the a priori knowledge that the measurements across multiple sensors share a common sparse support in a discretized target state space and provides a computationally efficient approach for centralized...
This paper considers a distributed network of through-the-wall radars for accurate indoor scene reconstruction in the presence of multipath propagation. A sparsity based method is proposed for eliminating ghost targets under imperfect knowledge of interior wall locations. Instead of aggregating and processing the observations at a central fusion station, joint scene reconstruction and estimation of...
The performance of the frequency diverse array (FDA) radar is fundamentally limited by the geometry of the array and the frequency offset. In this paper, we overcome this limitation by introducing a novel sparsity-based multi-target localization approach incorporating both coprime array and coprime frequency offset. The covariance matrix of the received signals corresponding to all sensors and employed...
Dual-function radar-communication (DFRC) systems enable information embedding into the radar signal emission. Existing methods for non-coherent phase-modulation DFRC employ multiple pairs of orthogonal waveforms and embed one communication symbol into each pair. The total number of symbols is equal to one-half of the number of waveforms. In this paper, we propose a new signaling strategy for embedding...
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