• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.709-709
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• 2006

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.204-210
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• 2012

In this paper, we study the method of estimating direction of departure(DOD) and direction of arrival(DOA) using estimation of signal parameters via rotational invariant techniques (ESPRIT) in uniform linear array MIMO radar system. While it is possible to improve the resolution by increasing the numbers of physical antennas and snapshots after matched filtering, such methods generally give rise to increase in complexity. In this paper, we propose to improve the resolution by optimally allocating the number of transmit and receive antennas. In particular, we show that the performance is optimized when the number of the receive antennas is approximately twice that of transmit antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1414-1419
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• 2000

In this paper, we propose a resolution enhancement method for estimating direction-of-arrival (DOA) of narrowband incoherent signals incident on a general array. The resolution of DOA algorithm is dependent on the aperture size of antenna array. But it is very impractical to increase the physical size of antenna array in real environment. Therefore we propose the method that increases the aperture size by virtually expanding the sensor spacing of original antenna array and then construct the steering matrix of the virtual array using the proper transformation matrix. Superior resolution capabilities achieved with this method are shown by simulation results in comparison with the standard MUSIC for incoherent signals incident on a uniform circular array.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1201-1208
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• 2009

The Direction-Of-Arrival(DOA) resolution of signals depends on the aperture size of the array. Therefore it is not easy to resolve closely spaced coherent signals impinge on an array with a small radius. In order to overcome the problem, a new method is proposed to use the characteristic of spatial spectrums for arrays which have different aperture sizes after virtually expanding the spacing of original antenna array. In case of coherent signals impinge on an uniform circular array, the perfect DOA resolution capability of 100 % is achieved at the SNR range of -10 dB to 0 dB by the Deterministic Maximum Likelihood(DML) algorithm including the proposed method. On the other hand, the standard DML algorithm can not resolve signals at all at the same SNR.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.703-705
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• 1999

In this paper, we introduce the direction of arrival(DOA) estimation of distributed signal based on the improved ESPRIT algorithm. Most research on the estimation of DOA has been performed based on the assumption that the signal sources are point sources. However, we consider a two-dimensional distributed signal source model using improved ESPRIT algorithm. In the distributed signal source model, a source is represented by two parameters, the azimuth angle and elevation angle. We address the estimation of the elevation and azimuth angles of distributed sources based on the parametric source modeling in the three-dimensional space with two uniform linear arrays. The array output vector is obtained by integrating a steering vector over all direction of arrival with the weighting of a distributed source density function. We also develop an efficient estimation procedures that can reduce the computational complexity. Some examples are shown to demonstrate explicity the estimation procedures under the distributed signal source model.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.18-26
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• 2006

In this paper, we propose new beamforming algorithm which overcomes signal cancellation effect even high cross correlation existing between target and interfering signal. Using the proposed method, we show that direction of arrival (DOA) of interfering signal can be estimated using correlation matrix and the cross-correlation can be eliminated in the correlation matrix of input signal. The proposed method gives high performance enhancement compared with the spatial averaging method in our computer simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1534-1542
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• 1997

In this paper, we present a performance improvement method for the direction-of-arrival (DOA) estimation algorithm of the narrowband signals incident on a uniform circular array. It is very important to estimate the covariance matrix effectively because the performance of DOA algorithm mainly depends on the exactness of the sampel coveriance matrix which is computed from the received samples of signals. In case of uniform circular array with the even number sensors, the structure of the arrray has a useful geometrical property. Therefore we present the method which can estimate covariance matrix more effectively using this property. The simulation results are shown to demonstrate the superior perfodrmance obtained by the proposed covariance matrix estimation method relative to that of the conventional estimation method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.917-920
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• 2016

SpSF algorithm is direction-of-arrival estimation algorithm based on sparse representation of incident signlas. Cost function to be optimized for DOA estimation is multi-dimensional nonlinear function, which is hard to handle for optimization. After some manipulation, the problem can be cast into convex optimiztion problem. Convex optimization problem tuns out to be constrained optimization problem, where the parameter in the constraint has to be determined. The solution of the convex optimization problem is dependent on the specific parameter value in the constraint. In this paper, we propose a rule-of-thumb for determining the parameter value in the constraint. Based on the fact that the noise in the array elements is complex Gaussian distributed with zero mean, the average of the Frobenius norm of the matrix in the constraint can be rigorously derived. The parameter in the constrint is set to be two times the average of the Frobenius norm of the matrix in the constraint. It is shown that the SpSF algorithm actually works with the parameter value set by the method proposed in this paper.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.53-64
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• 2004

This paper proposes a monopulse beamforming network to estimate a target angle in interference conditions. The proposed system estimates the target direction of arrival (DOA) with two separate beamformings for azimuth and elevation with a planar may. The elevation is extracted from adaptive beamforming in the azimuth direction and the azimuth from adaptive beamforming in the elevation direction. Unlike conventional monopulse beamforming techniques using complex correction formulas or a cascaded architecture of an adaptive array and a mainlobe canceller, the proposed system is very efficient from the computational complexity. The advantage is from fact that the monopulse ratio of the proposed system does not depend on the adapted weights. Moreover, the proposed system can estimate the DOA of the target even for multiple mainlobe interferences since it does not need my kinds of mainlobe maintenance technique.

• The Journal of the Acoustical Society of Korea
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• v.24 no.1
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• pp.1-10
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• 2005

This paper presents a wideband LPA (local polynomial approximation) beamforming algorithm that is appropriate for wideband moving sources. The Proposed wideband LPA algorithm adopts STMV (steered minimum variance) method that utilizes a steered covariance matrix obtained from multiple frequency components in one data snapshot, instead of multiple data snapshots in one frequency bin. The wideband LPA cost function is formed using STMV weight vector. The Proposed algorithm searches for the instantaneous DOA and angular velocity that maximize the wideband LPA cost function. resulting in a higher resolution performance than that of a DS LPA beamforming algorithm. Several simulations using artificial data and sea trial data are used to demonstrate the performance of the Proposed algorithm.