• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.101-105
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• 2004

The purpose of the study is to develop ship's bearing sensor using CPS receiver which can play a role as a ship's secondary compass. In this research, two GPS receivers are used to determine the bearing in real time. Then we investigated the bearing accuracy associated with the error pattern of two GPS receivers. Especially, the results are as follows ; - The investigation on the system design of GPS-Compass - The modeling to compute heading of sailing - The analysis on bearing accuracy with the error pattern - The defining possibility to play a role as a ship's secondary compass

• 전자공학회논문지 IE
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• v.43 no.3
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• pp.13-21
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• 2006

Ryu et al. proposed a multiple target angle tracking algorithm using the angular measurement obtained from the signal subspace estimated by the output of sensor array. Ryu's algorithm has good features that it has no data association problem and simple structure. But its performance is seriously degraded in the low signal-to-noise ratio, and it uses the angular measurement obtained from the signal subspace of sampling time, even though the signal subspace is continuously updated by the output of sensor array. For improving the tracking performance of Ryu's algorithm, a measurement fusion method is derived based on ML(Maximum Likelihood) in this paper, and it admits us to use the angular measurements obtained form the adjacent signal subspaces as well as the signal subspace of sampling time. The new target angle tracking algorithm is proposed using the derived measurement fusion method. The proposed algorithm has a better tracking performance than that of Ryu's algorithm and it sustains the good features of Ryu's algorithm.

• Defense and Technology
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• no.11 s.165
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• pp.34-35
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• 1992

• Defense and Technology
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• no.11 s.165
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• pp.44-45
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• 1992

• The Journal of the Acoustical Society of Korea
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• v.24 no.4
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• pp.230-237
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• 2005

The angle-tracking of maneuvering targets is required to the state estimation and classification of targets in underwater acoustic systems. The Problem of angle-tracking multiple closed and crossing targets has been studied by various authors. Sword et al. Proposed a multiple target an91e-tracking algorithm using angular innovations of the targets during a sampling Period are estimated in the least square sense using the most recent estimate of the sensor output covariance matrix. This algorithm has attractive features of simple structure and avoidance of data association problem. Ryu et al. recently Proposed an effective multiple target angle-tracking algorithm which can obtain the angular innovations of the targets from a signal subspace instead of the sensor output covariance matrix. Hwang et al. improved the computational performance of a multiple target angle-tracking algorithm based on the fact that the steering vector and the noise subspace are orthogonal. These algorithms. however. are ineffective when a subset of the incident sources are coherent. In this Paper, we proposed a new multiple target angle-tracking algorithm for coherent and incoherent sources. The proposed algorithm uses the relationship between source steering vectors and the signal eigenvectors which are multiplied noise covariance matrix. The computer simulation results demonstrate the improved Performance of the Proposed algorithm.

• Proceedings of the Acoustical Society of Korea Conference
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• 1993.06a
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• pp.222-225
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• 1993

일반적임 빔 형성기는 표적의 방위탐지가 가능하지만, 구조적인 특성상 대칭적인 빔을 형성하므로 표적의 좌/우 방위 구분이 불가능하기 때문에 표적의 정확한 방위를 탐지하고자 할 때 좌/우 구분이 가능한 빔 형성기가 필수적이다. 좌/우 분리 빔 형성 기법으로는 카디오이드(Cardioid) 빔 형성기법을 일반적인 빔 형성기에 적용시키는 방법이 최적으로 알려져 왔다. 그러나 좌/우 분리 빔을 형성하기 위해서는 많은 연산량과 하드웨어 설계에 대한 고려가 있어야한다. 본 논문에서는 좌/우 분리 빔 형성을 위하여 주파수 빔 형성기법과 카디오이드 빔 형성기법을 합성하여 적용하였다. 주파수 빔 형성 기법은 짧은 수행시간 동안에 표적의 정보추출을 위하여 고려되었으며, 카디오이드 빔 형성기법은 3개의 센서를 이용하여 센서의 기울기를 보상하여 수행하는 기법을 적용하였다. 또한 방향성 있는 시뮬레이션 신호를 생성하여 좌/우 분리 빔 형성 시뮬레이션을 수행하였다.

• Journal of KSNVE
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• v.10 no.5
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• pp.886-891
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• 2000

In this paper, an iterative array shape estimation technique is presented, which is based on the use of the least squares polynomial fitting to the data from heading sensors. The estimated polynomial shape model is then used for calculating the hydrophone positions on the assumption that the arc distances between sensors are constant. In order to verify the applicability of the proposed algorithm, numerical simulations are performed using two types of non-linear array shapes. In addition the noise effects of heading sensors on the array shape estimation results and the performance of beamformer are also investigated.

• Defense and Technology
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• no.6 s.160
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• pp.48-53
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• 1992

레이다 센서를 선진국 수준으로 개발하지 않으면 국방을 포기하는 것과 같기 때문에, 미래 국제사회에서 한 민족과 국가가 생존하려면 반드시 극복해야할 국방기술의 하나인 레이다 센서에 대하여 감당하기 어렵고 무모할 정도의 투자와 함께, 레이다 관련 종사자들의 피나는 노력만이 선진국과의 격차를 줄이는 길이다

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.109-116
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• 2004

This paper deals with data association using 3 sets of passive linear array sonars (PUS) geometrically positioned in a Y-shaped configuration, but fixed in an underwater environment. The data association problem is directly transformed into a 3-D assignment problem, which is known to be NP-hard. For generic passive sensors, it can be sotted using conventional algorithms, while it in PLAS becomes a formidable task due to the presence of bearing ambiguity. In particular, we proposed data association method robust to bearing measurements errors by incorporating frequency information and analyze a region of ghost problem by geometrical relation PUS and target. We analyzed the effectiveness of the proposed method by representative simulation in multi-target.

• The Journal of the Acoustical Society of Korea
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• v.30 no.8
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• pp.474-481
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• 2011

Conventional beamforming is ineffective in producing directional information in system with sparse degree of the freedom such as DIFAR (DIrectional Frequency Analysis and Recording) sonobuoy and in the presence of high directional noise. In this paper, Adaptive beamforming techniques are applied to produce directional spectra from a small number of sensors in highly directional noise environment. Conventional method as well as minimum variance and eigenvectors as adaptive method are evaluated via numerical test and real data.