• Title/Summary/Keyword: Horizontal array

Search Result 182, Processing Time 0.03 seconds

Multipath Track Association Technique using Characteristics of Conical Bearing in Horizontal Line Array Sonar (수평 선배열 소나의 원추각 특성 기반 다중경로 트랙 연관 기법)

  • Raegeun Oh
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.27 no.2
    • /
    • pp.156-166
    • /
    • 2024
  • This paper conducts a study on methods for associating multipath tracks received by a horizontal line array sonar. The horizontal line array sonar introduces conical bearing ambiguities due to its array-shaped characteristics. Target signals are often subject to multipath propagation in the ocean, resulting in errors in target bearing estimation due to these bearing ambiguities. Recent research efforts have been directed toward using multipath tracks to estimate the positions of targets. However, there has been a lack of research dedicated to identifying multipath tracks from the measurements of a horizontal line array sonar. Therefore, this study identifies the conical bearing characteristics of multipath signals based on the result of experiment and establishes criteria for associating multipath tracks. Additionally, Simulations are performed to determine the ability to associate multipath tracks.

Analysis and Tests of the Behavior of an Underwater Acoustic Horizontal Array Platform (수중음향 수평 배열 플랫폼의 거동 해석과 시험)

  • Lee, Chong-Moo;Kim, Kihun;Byun, Sung-Hoon
    • Journal of Ocean Engineering and Technology
    • /
    • v.32 no.4
    • /
    • pp.222-227
    • /
    • 2018
  • Most underwater acoustic arrays for low frequency operation are deployed vertically, but a mid-range frequency horizontal array system is being developed by the Korea Research Institute of Ships and Ocean Engineering (KRISO). The horizontal array platform is deployed underwater and kept in place by weather vaning mooring. This is essential because it is nearly impossible to keep a submerged body at a given position in the water without any external force. Hence, the horizontal array platform can maintain the desired position in the presence of a weak tidal current. The objective of this study is to design an underwater platform that can maintain its horizontal position in a weak current. First, the authors investigated various virtual models, selected one of the models, and performed a small model test of the selected model at a basin. We calculated the external forces associated with the 2D motion, and then we conducted a large basin test followed by a circulation water channel test for the manufactured array platform. The results of the simplified 2D motion calculation essentially matched the results of the underwater test.

Measurement of Horizontal Coherence Using a Line Array In Shallow Water

  • Park, Joung-Soo;Kim, Seong-Gil;Na, Young-Nam;Kim, Young-Gyu;Oh, Teak-Hwan;Na, Jung-Yul
    • The Journal of the Acoustical Society of Korea
    • /
    • v.22 no.2E
    • /
    • pp.78-86
    • /
    • 2003
  • We analyzed the measured acoustic field to explore the characteristics of a horizontal coherence in shallow water. Signal spatial coherence data were obtained in the continental shelf off the east coast of Korea using a horizontal line array. The array was deployed on the bottom of 130 m water depth and a sound source was towed at 26 m depth in the source-receiver ranges of 1-13 ㎞. The source transmitted 200 ㎐ pure tone. Topography and temperature profiles along the source track were measured to investigate the relationship between the horizontal coherence and environment variations. The beam bearing disturbance and array signal gain degradation is examined as parameters of horizontal coherence. The results show that the bearing disturbance is about ± 8° and seems to be affected by temporal variations of temperature caused by internal waves. The array signal gains show degradation more than 5㏈ by the temporal and spatial variations of temperature and by the down-sloped topography.

Effects of included angle on pool boiling of tube array having horizontal upper tube

  • Kang, Myeong-Gie
    • Nuclear Engineering and Technology
    • /
    • v.52 no.3
    • /
    • pp.530-537
    • /
    • 2020
  • This study investigates the effect of an included angle and heat flux on heat transfer of V-shape tube array having a horizontal upper tube. The test uses two stainless steel tubes with a smooth surface submerged under the water at atmospheric pressure. The angle varies from 2° to 24°. The heat transfer coefficient gets decreasing in consequence as the angle increases. The enhancement due to the lower tube is distinct as the heat flux is lower than 60 kW/㎡, where the effect of the convective flow is dominant. The present study and the published results show a similar tendency. Although the heat transfer coefficient for the present study is smaller than the symmetry case, enhanced heat transfer is observed compared to the tube array having a lower horizontal tube as the included angle is less than 10°.

Radiation Characteristics of Patch Antennas with an Array of Pins for Various Substrate Thicknesses (기판 두께에 따른 핀 배열을 가지는 패치 안테나의 방사 특성)

  • Cho, Myung-Ki;Kim, Tae-Young;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.46 no.10
    • /
    • pp.63-71
    • /
    • 2009
  • The patch antennas with an array of pins with excellent radiation characteristics are investigated for several substrate thicknesses. The patch length of a pin array patch antenna for the maximum suppression of radiation in the horizontal plane decreases as the substrate thickness increases. The radiation in the horizontal plane of a pin array patch antenna is very small compared to that of a conventional patch antenna. The increase of forward radiation and the decrease of backward radiation of a pin array patch are obtained compared to those of a conventional patch antenna. The half-power beamwidth of E-plane radiation pattern of a pin array patch antenna is narrow compared to that of a conventional patch antenna so that the directivity is improved.

Aspect Ratio Effect of the Natural Convection in Horizontal Enclosure with an Array of Square

  • Lee J.R.;Ha M.Y.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2003.10a
    • /
    • pp.286-288
    • /
    • 2003
  • The physical model considered here is a horizontal layer of fluid heated below and cooled above with a periodic array of evenly spaced square cylinders placed at the center of the layer, whose aspect ratio here varies from unity to six. Periodic boundary condition is employed along the horizontal direction to allow for lateral freedom for the convection cells. Two-dimensional solution for unsteady natural convection is obtained using an accurate and efficient Chebyshev spectral multi-domain methodology for a given Rayleigh numbers of $10^6$

  • PDF

SIW Slot Array Antenna for Dual-Polarization Phased Array System (이중 편파 위상 배열 시스템을 위한 기판 집적 슬롯 배열 안테나)

  • Cho, Dae-Keun;Byun, Jin-Do;Lee, Hai-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.22 no.2
    • /
    • pp.228-235
    • /
    • 2011
  • In this paper, we propose a $4{\times}8$ SIW(Substrate Integrated Waveguide) slot array antenna for dual-polarized phased array system. The basic part of the array is a subarray comprising an vertical-polarization and horizontal-polarization. A vertical-polarization slotted SIW single-polarization linear array. Using SIW, A vertical polarization linear array consists of 8 uniform longitudinal slots and 4-way SIW feeding network. Using HMSIW, horizontal-polarization linear array consists of 8 slots and 4-way SIW feeding network.

Design of beam steering dipole phased array antenna systems for IMT-2000 base station (IMT-2000 기지국용 빔 조향 다이폴 위상배열 안테나 시스템 설계)

  • 이상수;김명철;최학근
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.41 no.2
    • /
    • pp.41-51
    • /
    • 2004
  • In this paper, the beam steering dipole phased array antenna systems for IMT-2000 base station have been designed. The designed beam steering dipole phased array antenna systems are constituted by the antenna part and the beam steering control system part. The antenna part is designed by the proposed flat dipole for the broadband characteristics, and the 8${\times}$8 dipole array antenna is constructed by the proposed flat dipole for the directional radiation pattern. Besides the vertical power divider is designed for the vertical power distribution. The beam steering control system part is designed the horizontal power divider for the horizontal power distribution, the 4-bit phase shifters and the driving circuit of phase shifters for the horizontal beam tilting. In order to evaluate a performance of the designed antenna systems, they were fabricated and the radiation characteristics were measured. From the measured results, we found that the horizontal beams were tilted by the each control signals, and the measured radiation characteristics showed good agreement with the design goals.

Development of a position sensitive CsI(Tl) crystal array

  • Shi, Guo-Zhu;Chen, Ruo-Fu;Chen, Kun;Shen, Ai-Hua;Zhang, Xiu-Ling;Chen, Jin-Da;Du, Cheng-Ming;Hu, Zheng-Guo;Fan, Guang-Wei
    • Nuclear Engineering and Technology
    • /
    • v.52 no.4
    • /
    • pp.835-840
    • /
    • 2020
  • A position-sensitive CsI(Tl) crystal array coupled with the multi-anode position sensitive photomultiplier tube (PS-PMT), Hamamatsu H8500C, has been developed at the Institute of Modern Physics. An effective, fast, and economical readout circuit based on discretized positioning circuit (DPC) bridge was designed for the 64-channel multi-anode flat panel PSPMT. The horizontal and vertical position resolutions are 0.58 mm and 0.63 mm respectively for the 1.0 × 1.0 × 5.0 ㎣ CsI(Tl) array, and the horizontal and vertical position resolutions are 0.86 mm and 0.80 mm respectively for the 2.0 × 2.0 × 10.0 ㎣ CsI(Tl) array. These results show that the CsI(Tl) crystal array with low cost could be applied in the fields of medical imaging and high-resolution gamma camera.

Effect of the Pin Radius on the Radiation Characteristics of a Patch Antenna with an Array of Pins Interconnecting the Patch and the Ground (패치와 접지면 사이에 삽입된 핀 배열을 가지는 안테나의 방사특성에 핀 반경이 미치는 효과)

  • Lee, Woo-Ram;Kim, Tae-Young;Kim, Boo-Gyoun;Shin, Jong-Dug
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.45 no.10
    • /
    • pp.80-89
    • /
    • 2008
  • Patch antennas with an array of pins interconnecting the patch and the ground (Pin array patch antennas) are fabricated and their characteristics are measured. The radiation characteristics of pin array patch antennas are compared to those of conventional patch antennas. The suppressions of the radiation in horizontal directions in E-plane and H-plane are more than 10 dB and 4 dB, respectively. The forward radiation is increased, while the backward radiation is decreased. The directivity is improved because the half-power beamwidth of radiation patterns in both E-plane and H-plane is reduced. The resonance frequency of a pin array patch antenna increases as the pin radius of a pin amy patch antenna increases. An optimum pin radius of a pin array patch antenna exists for the maximum suppression of the radiation in horizontal directions.