The following topics were dealt with: beamforming; direction-of-arrival estimation; tracking; multi-sensors application; multi-channel processing; sensorarrayprocessing; MIMO processing; space-time coding; synthetic...
The following topics were dealt with: beamforming; direction-of-arrival estimation; tracking; multi-sensors application; multi-channel processing; sensorarrayprocessing; MIMO processing; space-time coding; synthetic aperture space-time processing; imaging; space-time processing for radar; sensor networking; sensor management; sonar; and microphone arrayprocessing
Recently, the authors proposed a miniaturized microphone array not utilizing the phase difference but utilizing the directivity of each microphone, namely aggregated microphones. We have already showed that the phased...
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ISBN:
(纸本)1424403081
Recently, the authors proposed a miniaturized microphone array not utilizing the phase difference but utilizing the directivity of each microphone, namely aggregated microphones. We have already showed that the phased microphone array and the aggregated microphones can be described within the same framework. We have also showed that it is possible to apply the aggregated microphones to the various methods of the phased microphone array. However, the difference of the performance between the phased array and the aggregated microphones has not been evaluated yet. The effect of the directivity and the posture of each microphone on the performance of the aggregated microphones has not also been evaluated yet. In this paper, we evaluate the performance of DCMP (Directionally Constrained Minimization of Power) adaptive array utilizing aggregated microphones.
For low frequency observations (< 300 MHz) the radio astronomical community is currently developing a number of new instruments such as the low frequency array (LOFAR), the Mileura wide field array (MWA) and the pr...
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ISBN:
(纸本)1424403081
For low frequency observations (< 300 MHz) the radio astronomical community is currently developing a number of new instruments such as the low frequency array (LOFAR), the Mileura wide field array (MWA) and the primeval structure telescope (PaST). These telescopes require new calibration algorithms since phased arrays require an all-sky approach to imaging and calibration. This implies that the calibration will generally have to deal with a multitude of sources. In this paper we will discuss a muldsource calibration method to estimate the gains and phases of the receiving elements without having to solve for the receiver noise powers at the same time. Our method is able to handle arbitrary known source models. We will show that the proposed algorithm is asymptotically efficient by comparing the results from Monte Carlo simulations with the Craimer-Rao bound for the underlying data model.
This paper presents a novel synthetic aperture method, which can be used to reduce the average sidelobe level of a random spherical volumetric array. The technique exploits a general property of random arrays in which...
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ISBN:
(纸本)1424403081
This paper presents a novel synthetic aperture method, which can be used to reduce the average sidelobe level of a random spherical volumetric array. The technique exploits a general property of random arrays in which the average sidelobe level is inversely proportional to the number of elements present.
For a set of T independent N-variate Gaussian training samples (T < N), we derive a test for discriminating between stationary autoregressive models of order m, AR(m), and time-varying autoregressive models of orde...
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ISBN:
(纸本)1424403081
For a set of T independent N-variate Gaussian training samples (T < N), we derive a test for discriminating between stationary autoregressive models of order m, AR(m), and time-varying autoregressive models of order m, TVAR(m).
Multifunction phased array systems with radar, telecom, and imaging applications have already been established for flat plate phased arrays of dipoles, or waveguides. In this paper the design trades and candidate opti...
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ISBN:
(纸本)1424403081
Multifunction phased array systems with radar, telecom, and imaging applications have already been established for flat plate phased arrays of dipoles, or waveguides. In this paper the design trades and candidate options for combining the radar and telecom functions of the deep space network (DSN) into a single large transmit array of small parabolic reflectors will be discussed. In particular the effect of combing the radar and telecom functions on the sizes of individual antenna apertures and the corresponding spacing between the antenna elements of the array will be analyzed. A heterogeneous architecture for the DSN large transmit array is proposed to meet the radar and telecom requirements while considering the budget, scheduling, and strategic planning constrains.
In this paper, an alternative Target Density Function (TDF) is proposed to image the radar targets in a dense target environment. It is obtained by considering a novel range and scanning angle plane different from the...
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ISBN:
(纸本)1424403081
In this paper, an alternative Target Density Function (TDF) is proposed to image the radar targets in a dense target environment. It is obtained by considering a novel range and scanning angle plane different from the conventional methods. An alternative method is briefly proposed for smoothing the target density function by taking advantage of Walsh functions. Although the imaging is obtained via the phased array radars, the problem associated with beamforming in linear phased array radar system is bypassed in this new algorithm.
In radio astronomy images are made of astronomical objects as they appear at radio frequencies using a technique called aperture synthesis. Signats from several antennas are correlated and integrated over time. The da...
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ISBN:
(纸本)1424403081
In radio astronomy images are made of astronomical objects as they appear at radio frequencies using a technique called aperture synthesis. Signats from several antennas are correlated and integrated over time. The data collected over several hours are further processed to calibrate the instrument and to form an image or intensity map. The calibration and imaging algorithms do not use the autocorrelations because the receiver noise is unstable and hence considered unknown. In literature the Cramer Rao Bound for the calibration problem has been derived assuming that the autocorrelations are part of the available data. If the assumption is correct that the autocorrelations do not contain useful information when the receiver noise is unknown, than the CRB for the case that the autocorrelations are not part of the data will be the same. In this paper we will derive the CRB excluding the autocorrelations and show that it indeed does not matter whether the autocorrelations are included or not.
We describe a method of tuning a simple detection process of stationary targets in SAR images. The tuning metric accounts for the squared-error performance of prescient estimators of target location and reflectivity. ...
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ISBN:
(纸本)1424403081
We describe a method of tuning a simple detection process of stationary targets in SAR images. The tuning metric accounts for the squared-error performance of prescient estimators of target location and reflectivity. The efficiencies of these prescient estimators are compared to their Cramer Rao bounds (CRBs). The off-line tuning is performed by collecting statistics of scatterer estimation in SAR images created using sparse-array spotlight mode simulations.
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...
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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).
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