• Proceedings of the Acoustical Society of Korea Conference
• /
• 1996.06a
• /
• pp.18-21
• /
• 1996

예인형 선배열 소나에서 기존의 선배열 빔형성 기법을 적용하면 예인함 기동시 선배열 형상 변형에 의해 심각한 성능 저하 현상이 나타난다. 이러한 문제 해결을 위해 센서배열 변형을 고려한 견실한 빔형성 기법은 선배열 형상 추정을 위해 칼만필터를 이용한 형상 추정기법을 이용하고, 변형보상 빔형성을 위해 선배열 세그먼트 기울기 추정값을 이용하는 변형보상 빔형성 알고리즘을 제안하였다. 제안된 기법을 기존의 빔형성 기법을 적용하여 시뮬레이션에 의해 제안된 기법의 보상성능을 입증 하였다.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.85-88
• /
• 2000

가늘고 긴 선배열을 해상에서 운용할 때 비선형 형상이 유도되므로 음원에 대한 정확한 탐지를 위하여 배열형상 추정이 필요하다. 방위센서를 이용한 배열형상 추정을 위하여 배열의 천 정도가 적은 경우에만 적용 가능한 다항 근사화 방법의 제한점을 극복하기 위하여 반복법을 제안하고, 수치 시뮬레이션을 통하여 반복회수에 따른 배열형상 추정결과를 분석하였다

• The Journal of the Acoustical Society of Korea
• /
• v.39 no.4
• /
• pp.255-262
• /
• 2020

In modern passive sonar systems, a towed array sensor is used to minimize the effects of own ship noise and to get a higher SNR. The thin and long towed array sensor can be guided in a non-linear form according to the maneuvering of tow-ship. If this change of the array shape is not considered, the performance of beamformer may deteriorate. In order to properly beamform the elements in the array, an accurate estimate of the array shape is required. Various techniques exist for estimating the shape of the linear array. In the case of a method using a heading sensor, the estimation performance may be degraded due to the effect of heading sensor noise. As means of removing this potential error, weighted polynomial fitting technique for estimating array shape is developed here. In order to evaluate the performance of proposed method, we conducted computer simulation. From the experiments, it was confirmed that the proposed method is more robust to noise than the conventional method.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.8
• /
• pp.74-80
• /
• 2001

Because of ocean waves, swell, steering corrections, etc, the hydrophones of a towed array will not live along a straight line. However the degradation of bearing estimation performance occurs when beamforming is carried out on the hydrophone outputs of an acoustic towed array which is not straight. So it is required to estimate the shape of the array for the improved beamformer output. 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 estimation error and the influence of deformations on the performance of the conventional beamformer output are investigated. Finally, the suggested method is applied to the real system in order to investigate the applicability.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.2 s.25
• /
• pp.20-25
• /
• 2006

Low frequency towed line array with high array gain and beam resolution is a long range surveillance sensor for anti-submarine warfare. The beam characteristics is however deteriorated due to the distorted line array sensor caused by low towing speed, wind, current, and towing ship maneuvering. An adaptive beamforming method is utilized in this paper to enhance the distorted line array beam performance by estimating and compensating the nonlinear array shape. A polynomial curve fitting in the least square sense is used to estimate the array shape iteratively with the distributed heading sensors data along the array. Real time array shape estimation and nonlinear array beam calculation is applied to a very long towed line array sensor system and the beam performance is evaluated and compared to the linear beamformer for the simulation and sea trial data.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1998.06e
• /
• pp.151-154
• /
• 1998

이 논문에서 비선형 배열 MUSIC 빔형성 기법을 이용하여 예인형 선배열 센서 시스템의 표적 좌우 방위 분리 방법을 기술하였다. 이 기법은 배열 운동모델 Water-Pully 모델과 방향센서의 정보를 이용하는 칼만필터를 설계하여 예인함 기동에 따른 배열형상을 추정하고 표적의 좌우방위를 분리하기 위하여 추정된 배열형상에서 MUSIC 빔형성 기법으로 신호처리를 수행하였다. 또한 예인주기와 예인진폭과 같은 예인함 기동형태의 전형적인 빔형성 기법과 MUSIC 빔형성 기법으로 표적의 좌우 방위 분리 성능을 비교 분석하였다.

• The Journal of the Acoustical Society of Korea
• /
• v.23 no.5
• /
• pp.370-375
• /
• 2004

This paper proposes an algorithm that estimates three dimensional array shape calibration about the bottom-mounted sensor array. under the assumption that the active sources are in the far-field with unknown positions. Under some assumptions. we calculate the sensor positions via an algebraic solutions of a least squares problem that the linear equations are related to the sensor positions and directions or arrival. We give examples of algorithm performance from both computer simulations and sea test. We also illustrate the performance of sensor positions estimation as a function of time delay estimation variance and the distribution of the localizing sources.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.2
• /
• pp.1-6
• /
• 2005

Ryu et al. proposed a multiple target DOA tracking algorithm using a linear sensor array. In Ryu's algorithm first, the signal subspace is estimated using sensor output and the angular innovations of targets are extracted from the estimated signal subspace. Next, the DOA's of targets are tracked using the angular innovations as the inputs of Kalman filters. Ryu's algorithm has good features that it has no data association problem and is efficient. However, Ryu's algorithm can't be a lied to an arbitrarily shaped array because it was proposed using linear sensor array. Actually, when the sensor array is used in the various application fields, sensors have a position error. Therefore, the sensor array can be an arbitrarily shaped array. In this paper, we propose a multiple target DOA tracking algorithm applicable to an arbitrarily shaped array, and it sustains the good features of Ryu's algorithm.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.2
• /
• pp.155-162
• /
• 2016

TASS(Towed Array Sonar System) is a sonar system which tows the sensor array behind a platform. Array shape is generally assumed to be a straight line. But the array shape is often distorted by oceanic current or platform maneuvering which causes the performance loss of signal processing method like beamforming. So array shape estimation methods are needed. Typically the method based on Kalman filter using heading sensor is used. In practice, the measurement is corrupted by biases which are caused by rotation of the tow cable, varying magnetic fields and slowly varying stresses in the mechanical construction. Although they can't be calibrated but can be estimated. In this paper, we suggest the array shape estimation method based on Kalman filter compensating the sensor biases.