Recently, nonlinear blind compensation technique has attracted growing attention in array signal processing application. However, due to the nonlinear distortion stemming from array receiver which consists of multi-ch...
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Recently, nonlinear blind compensation technique has attracted growing attention in array signal processing application. However, due to the nonlinear distortion stemming from array receiver which consists of multi-channel radio frequency (RF) front-ends, it is too difficult to estimate the parameters of arraysignal accurately. A novel nonlinear blind compensation algorithm aims at the nonlinearity mitigation of array receiver and its spurious-free dynamic range (SFDR) improvement, which will be more precise to estimate the parameters of target signals such as their two-dimensional directions of arrival (2-D DOAs). Herein, the suggested method is designed as follows: the nonlinear model parameters of any channel of RF front-end are extracted to synchronously compensate the nonlinear distortion of the entire receiver. Furthermore, a verification experiment on the arraysignal from a uniform circular array (UCA) is adopted to testify the validity of our approach. The real-world experimental results show that the SFDR of the receiver is enhanced, leading to a significant improvement of the 2-D DOAs estimation performance for weak target signals. And these results demonstrate that our nonlinear blind compensation algorithm is effective to estimate the parameters of weak arraysignal in concomitance with strong jammers.
This paper presents a novel and efficient extrema-mapping algorithm, which we call the roller-coaster algorithm. Two versions of the algorithm, the one-dimensional (1-D) and the two-dimensional (2-D) roller-coaster, a...
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This paper presents a novel and efficient extrema-mapping algorithm, which we call the roller-coaster algorithm. Two versions of the algorithm, the one-dimensional (1-D) and the two-dimensional (2-D) roller-coaster, are developed. Its applicability to array signal processing is demonstrated. We use it to solve a multiple source direction finding problem using multiple signal classification (MUSIC), beamformer, and minimum variance methods, and for antenna array design. The algorithm is based on heuristic assumptions and its properties are not proved. Yet, its performance was tested in many simulated experiments, yielding favorable results.
We have developed a signal-processing method for array data recorded at densely and widely distributed tiltmeter stations in Japan and analyzed the data recorded during the last 5 years. Filtered seismograms were anal...
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We have developed a signal-processing method for array data recorded at densely and widely distributed tiltmeter stations in Japan and analyzed the data recorded during the last 5 years. Filtered seismograms were analyzed to detect coherent seismic waves and estimate the epicenters. In order to identify very-low frequency earthquakes (VLFEs) with only low-frequency energies only, we selected only events not listed in the earthquake catalogue provided by the Japan Meteorological Agency from all of the detected events. The epicenters of the obtained VLFEs were estimated to be distributed not only along the Nankai Trough, where the events occurred on the reverse faults in the well-developed accretionary prism, but also in Tokachi-oki without accretion. This result suggests that even in such a region, VLFEs can occur on a shallower portion of the plate boundary than the seisrnogenic region of ordinary earthquakes and/or in a deformed area of the overriding plate along the subduction zone without accretion.
A front-end radar arrayprocessing system that operates in the subband domain is considered. It is assumed that pulse compression will be performed on radar return signals in the subband domain. A cohesive algorithm i...
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ISBN:
(纸本)0780363396
A front-end radar arrayprocessing system that operates in the subband domain is considered. It is assumed that pulse compression will be performed on radar return signals in the subband domain. A cohesive algorithm is presented that optimizes the design of all filters used in the subbanding process. These include the analysis filter (used to decompose return signals into narrowband components), the synthesis filter (used when combining subband components after processing), and the pulse compression generating filter (used to generate subband pulse compression filters from a wideband pulse compression filter). The algorithm attempts to minimize system aliasing noise, frequency distortion, and subband processing operations count.
Linear dimensionality reduction of signals observed by a sensor array is often useful in balancing the accuracy and speed of post-stage processing, especially in real-time systems with limited computational resources....
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ISBN:
(纸本)9781665405409
Linear dimensionality reduction of signals observed by a sensor array is often useful in balancing the accuracy and speed of post-stage processing, especially in real-time systems with limited computational resources. However, for multichannel time-series signals having time-invariant intertemporal and interchannel correlations, the direct application of frequency-wise linear dimensionality reduction method requires a large number of digital filters with large filter lengths, which is still unpreferable in the viewpoint of computational cost. We propose a frequency-independent, i.e., instantaneous, linear dimensionality reduction method that achieves low computational cost and latency and high restoration accuracy. We also show several results of numerical experiments to compare the proposed method with other instantaneous linear dimensionality reduction methods, i.e., the principal component analysis and element selection method, and demonstrate the effectiveness of the proposed method.
Modern direction finding (DF) methods usually use antenna arrays to receive information from an unknown radiation source, and further process the information in order to locate the transmission source. Small aperture ...
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ISBN:
(纸本)9781509013456
Modern direction finding (DF) methods usually use antenna arrays to receive information from an unknown radiation source, and further process the information in order to locate the transmission source. Small aperture array is easy to carry, install, deploy and operate because of small volume, light weight, and it is preferred to large aperture array, and is frequently used in many aspects such as the navigation of ships and aircrafts, locating interfering or illegal transmitters. But at the same time, small aperture array has poor performance in precision. This work demonstrates the signals received by small aperture array are processed coupled, and the differences between signals in amplitude and phase are amplified greatly, which makes it possible that small aperture array is able to have good performance.
An algorithm to automatically locate QRS complexes in noninvasive fetal ECG signals is described and was entered in the PhysioNet/CinC 2013 "Noninvasive Fetal ECG" challenge. The algorithm is based on an ite...
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ISBN:
(纸本)9781479908844
An algorithm to automatically locate QRS complexes in noninvasive fetal ECG signals is described and was entered in the PhysioNet/CinC 2013 "Noninvasive Fetal ECG" challenge. The algorithm is based on an iterative subspace decomposition and filtering of the maternal ECG components from the recordings of a set of electrodes placed on the mother's abdomen. Once the maternal components are removed, a novel merging technique is applied to merge the recordings and generate a signal with a higher SNR to perform fetal peak detection. The algorithm produces an annotation file for each data set containing the location of the fetal QRS complexes in that set. The final results indicate that the algorithm is able to detect fetal peaks under different scenarios and for variety of devices and signals encountered in clinical practice.
This paper addresses the problem of determining the Directions-of-Arrival (DOA's) of narrow-band emitter signals impinging on an antenna array. A modified beamspace MUSIC algorithm for high-resolution array proces...
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ISBN:
(纸本)9781424415847
This paper addresses the problem of determining the Directions-of-Arrival (DOA's) of narrow-band emitter signals impinging on an antenna array. A modified beamspace MUSIC algorithm for high-resolution arrayprocessing is presented. Simulation results are included to show the improved performance of proposed estimator at threshold signal-to-noise ratio.
Stochastic Maximum Likelihood (SML) is a popular direction of arrival (DOA) estimation technique in array signal processing. It is a parametric method that jointly estimates signal and instrument noise by maximum like...
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ISBN:
(纸本)9781728176055
Stochastic Maximum Likelihood (SML) is a popular direction of arrival (DOA) estimation technique in array signal processing. It is a parametric method that jointly estimates signal and instrument noise by maximum likelihood, achieving excellent statistical performance. Some drawbacks are the computational overhead as well as the limitation to a point-source data model with fewer sources than sensors. In this work, we propose a Sieved Maximum Likelihood (SiML) method. It uses a general functional data model, allowing an unrestricted number of arbitrarily-shaped sources to be recovered. To this end, we leverage functional analysis tools and express the data in terms of an infinite-dimensional sampling operator acting on a Gaussian random function. We show that SiML is computationally more efficient than traditional SML, resilient to noise, and results in much better accuracy than spectral-based methods.
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