A coprime array consists of two uniform linear subarrays that construct an effective difference co-array with certain desirable characteristics. In this paper, we propose a generalized coprime array concept through th...
详细信息
ISBN:
(纸本)9781479914814
A coprime array consists of two uniform linear subarrays that construct an effective difference co-array with certain desirable characteristics. In this paper, we propose a generalized coprime array concept through the compression of the interelement spacing of one constituting subarray. As such, the existing variations of coprime array and nested array structures are represented as special cases. The achievable unique lags as well as consecutive lags in the resulting virtual array are analytically expressed, and the direction-of-arrival estimation performance is examined using both the MUSIC algorithm and sparse signal reconstruction techniques.
This paper describes the problem caused by near-field sound sources. Formerly, the authors proposed a 2-ch passive subtractive beamformer with a single sharp notch for noise reduction. It is obvious that the single sh...
详细信息
ISBN:
(纸本)0780385454
This paper describes the problem caused by near-field sound sources. Formerly, the authors proposed a 2-ch passive subtractive beamformer with a single sharp notch for noise reduction. It is obvious that the single sharp notch is insufficient for dealing with near-field, non-point sound sources. To solve this problem, this paper presents the hybrid subtractive beamformer that is realized as a cascade connection of single subtractive beamformers. The number of connections depends on frequency to minimize the negative effect caused by spatial aliasing when an objective signal is assumed as a wide-band speech signal. The experimental results verifies that the hybrid beamformer has an advantage in reducing signal distortion over the original single subtractive beamformer.
We propose a scalable and energy efficient method for reconstructing a 'sparse' Gauss-Markov random field that is observed by an array of sensors and described over wireless channels to a fusion center. The en...
详细信息
ISBN:
(纸本)9781424422401
We propose a scalable and energy efficient method for reconstructing a 'sparse' Gauss-Markov random field that is observed by an array of sensors and described over wireless channels to a fusion center. The encoder is universal, i.e. invariant to the statistical model of the source and the channel, and is based on compressed sensing. The reconstruction algorithms exploit the a-priori statistical information about the field and the channel at the fusion center to yield a performance comparable to information theoretic bounds. Furthermore, by putting stringent constraints on the sensing matrix we avoid (or even eliminate) inter-sensor communication while suffering negligible degradation in performance.
Impulsive interference mitigation capabilities of robust array algorithms are considered in delay estimation of a direct sequence spread spectrum (DS/SS) system. The simulations are done in the environment where the d...
详细信息
ISBN:
(纸本)0780385454
Impulsive interference mitigation capabilities of robust array algorithms are considered in delay estimation of a direct sequence spread spectrum (DS/SS) system. The simulations are done in the environment where the direction of arrival (DOA) of individual impulses is either random or fixed. It is shown that the minimum variance distortionless response (MVDR) beamforming algorithm without any interference suppression algorithm is sufficient if impulses are arriving from a fixed DOA. In the random DOA case the performance of the MVDR beamformer algorithm alone is very poor and impulse suppression methods are needed. The paper compares four different impulse suppression methods. It is shown that the best algorithm allow over 60% of snapshots to be corrupted.
The fact that most of high-accuracy positioning and distributed timing services, including safety-critical operations, rely on Global Navigation Satellite Systems (GNSS) has raised the concern of possible denial-of-se...
详细信息
ISBN:
(纸本)9781479914814
The fact that most of high-accuracy positioning and distributed timing services, including safety-critical operations, rely on Global Navigation Satellite Systems (GNSS) has raised the concern of possible denial-of-service situations. Complementary to time-and frequency-domain mitigation techniques, it is well known that antenna-array based receivers can benefit from spatial domain processing and effectively mitigate unintentional and intentional Radio Frequency Interferences (RFIs). In this work, we propose a software-based GNSS receiver architecture that implements a real-time, array-based signal acquisition algorithm based on the Generalized Likelihood Ratio Test, combined with a null-steering spatial filter for signal tracking, showing its RFI rejection capabilities.
Compressive sensing (CS) has successfully been applied to reconstruct sparse signals and images from few observations. For multi-component nonstationary signals characterized by instantaneous frequency laws, the spars...
详细信息
ISBN:
(纸本)9781467310710
Compressive sensing (CS) has successfully been applied to reconstruct sparse signals and images from few observations. For multi-component nonstationary signals characterized by instantaneous frequency laws, the sparsity exhibits itself in the time-frequency domain as well as the ambiguity domain. In this paper, we examine CS in the context of nonstationary arrayprocessing. We show that the spatial averaging of the ambiguity function across the array improves the CS performance by reducing both noise and cross-terms. The corresponding time-frequency distribution which is reconstructed through L-1 minimizations yields significant improvement in time-frequency signature localizations and characterizations.
This paper develops a time reversal moving target detector based on array antennas. Time reversal utilizes the multipath effect by retransmitting the received signal containing the Doppler shift of the moving target. ...
详细信息
ISBN:
(纸本)9781728119465
This paper develops a time reversal moving target detector based on array antennas. Time reversal utilizes the multipath effect by retransmitting the received signal containing the Doppler shift of the moving target. Two detectors are derived in both conventional and time reversal scenarios, respectively. The Monte Carlo results show that the time reversal detector significantly improves the target detection probability in multipath environments compared with the conventional detector. The increase of multipath number is helpful to improve the detection probability of time reversal detector.
We consider the problem of estimating the parameters of linear chirp signals when received at a multi-sensor antenna. Exploiting the negligible variation of the parameters of interest over the coherence time of the ch...
详细信息
ISBN:
(纸本)0780385454
We consider the problem of estimating the parameters of linear chirp signals when received at a multi-sensor antenna. Exploiting the negligible variation of the parameters of interest over the coherence time of the channel, we derive a new data model that Outlines the space-time relation between the parameters. In the case of multiple chirps and single-path channels, the derived model allows the estimation of more signals than antennas. The model is directly employed in the case of a single chirp in multipath, where angles of arrival can be retrieved if more antennas than paths are available. We use a MUSIC-based estimator to recover the unknown parameters and compare its performance through simulations against the Cramer-Rao Bound.
作者：
Zatman, MMIT
Lincoln Lab Lexington MA 02420 USA
Most adaptive arrayprocessing schemes assume that the interference is 'wide sense stationary'. However, in practice this assumption is often violated. For example there may be motion of either the array and/o...
详细信息
ISBN:
(纸本)0780363396
Most adaptive arrayprocessing schemes assume that the interference is 'wide sense stationary'. However, in practice this assumption is often violated. For example there may be motion of either the array and/or the interference during the processing interval. The asymptotic performance of two adaptive beamforming algorithms which compensate for this type of changing interference scenario are analyzed in this paper.
Conventional MUSIC (MUltiple signal Classification)rraethod, which is a well-known super-resolution technique that employs amonostatic configuration, degrades severely when themultiple targets are deterministic becaus...
详细信息
ISBN:
(纸本)1424403081
Conventional MUSIC (MUltiple signal Classification)rraethod, which is a well-known super-resolution technique that employs amonostatic configuration, degrades severely when themultiple targets are deterministic because the rank of the covariancematrix collapses to the value of one regardless of the number of targets. FRM (Frequency Response Matrix) [2, 7], with its multistatic configuration, is also a super-resolution technique and can complament, MUSIC in the target randomness spectrum. This paper demonstrates that conventional MUSIC performs better for targets with strongly random (complex) amplitudes and FRM performs better for target with weakly random amplitudes (best for deterministic amplitudes).
暂无评论