• Title/Summary/Keyword: multi-beam

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Study on a Optical Storage Device Based on Multi-beam (다중빔을 이용한 광 저장 장치에 관한 연구)

  • Lee, Jeong-Hyeon;Han, Chang-Su;Kim, Su-Hyeon;Gwak, Yun-Geun
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.4
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    • pp.64-70
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    • 1999
  • A new multi-beam optical system is presented on the grounds of tri-positioning systems in this paper. The system has been developed to improve the data transfer rate for the optical disk system. The actuating system is composed of a tracking and focusing actuating system basically and a newly developed beam rotating actuator. The beam rotating actuator is employed in a multi-beam optical system to trace more than one track simultaneously. The multi-beam optics is established through the optical simulation and several experimental trials. The differential phase tracking method is used in the tracking error signal detection based on the only one beam spot. We also analyze the characteristics of multi-beam optical system. The experimental result shows that the multi-beam positioning system has performance adequate to the multi-beam optical disk system.

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An Angular Independent Backscattered Amplitude Imagery of Multi-Beam Echo Sounder for Sediment Boundary Extraction

  • Park, Jo-Seph;Kim, Hi-Kil;Park, Seong-ho
    • Proceedings of the KSRS Conference
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    • pp.663-663
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    • 2002
  • The National Oceanographic Research Institute of KOREA started to survey for the basic data necessary to territorial sea and EEZ identification and marine development with Multi-Beam Echo Sounder(L3 SeaBeam 2112) since 1996. The Multi-Beam surveys has provided a very new and precise way of describing the morphology and nature of the underwater seabed. Multi-Beam Echo Sounder systems employ sound waves propagating at angles which vary from vertical to nearly horizontal. The locations on the bottom where echoes are generated cover a swath whose port to starboard width may be equal to many times the water depth. Newer Multi-beam bathymetric sonars provide both a beam by beam depth and backscatter amplitude of the bottom. But The backscattered amplitude didn't use for identification of bottom properties because backscatter amplitude effects by the many environmental variables of underwater and seabed. We investigates the utilization of geo-referenced backscatter amplitude and analysis of relationship between The Backscattered Amplitude and Sidescan Sonar imagery from Sea Beam 2112. For the backscattered amplitude imagery mainly represents the properties of sediment, we computed the beam geometry, time-varied amplifier gain, and mainly incidence angle to the topography using bathymetric model at each ping. In this paper, those issues are illustrated, and the angular independent imagery based on swath topographic model is described.

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A NEXT GENERATION MULTI-BEAM FOCAL PLANE ARRAY RECEIVER OF TRAO FOR 86-115 GHZ BAND

  • Chung Moon-Hee;Khaikin Vladimir B.;Kim Hyo-Ryoung;Lee Chang-Hoon;Kim Kwang-Dong;Park Ki-Won
    • Journal of Astronomy and Space Sciences
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    • v.23 no.1
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    • pp.19-28
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    • 2006
  • The noise temperature of existing millimeter-wave receivers is already within two or three times quantum noise limit. One of practical ways to increase the observation speed of single dish radio telescope without longer integration time is use of multi-beam focal plane array receiver as demonstrated in several large single dish radio telescopes. In this context the TRAO (Taeduk Radio Astronomy Observatory), which operates a 143n Cassegrain radio telescope, is planning to develop a 4 x 4 beams focal plane array SIS receiver system for 86-115 GHz band. Even though millimeter-wave HEMT LNA-based receivers approach the noise temperature comparable to the SIS receiver at W-band, it is believed that the receiver based on SIS mixer seems to offer a bit more advantages. The critical part of the multi-beam array receiver will be sideband separating SIS mixers. Employing such a type of SIS mixer makes it possible to simplify the quasi-optics of receiver. Otherwise, an SSB filter should be used in front of the mixer or some sophisticated post-processing of observation data is needed. In this paper we will present a preliminary design concept and components needed for the development of a new 3 mm band multi-beam focal plane array receiver.

Multi-beam Antenna Analysis

  • Lee, Jeom-Hun;Oh, Seung-Hyeub
    • International Journal of Aeronautical and Space Sciences
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    • v.5 no.2
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    • pp.71-76
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    • 2004
  • This paper describes the antenna analysis of the multi-beam for communicationsatellite. The design core parameters of the antenna system are optimal antennadiameter, feed horn type and hom size, F/D, and the coordinate of offset horns. Thepaper deals with the method to determine design core parameters of optimal antennadiameter, feed horn type and horn size. F/D, and the coordinate of offset horns, andthe performances of design result.

Management after installation of artificial reefs;Present Condition and Development Scheme (인공어초 사후관리 현황과 발전방향)

  • Lee, Sung-Il;Ahn, Seung-Hwan;Kim, Dong-Sun
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • pp.160-161
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    • 2005
  • It is important to manage artificial fish reefs with installation for restoration. The instruments of survey for artificial reefs condition(location, amount etc.) is Side Scan Sonar and Multi-beam sonar. The efficient and economic survey of the artificial reefs facility is the complete survey of the SSS(Side Scan Sonar) in all area first and then the survey of the artificial reefs by MBES(Multi Beam Echo Sounder) in the finding area.

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DESIGN OF THE IF DISTRIBUTOR AND V/F CONVERTER FOR RECEIVER SYSTEM (우주전파 수신기를 위한 IF 분배기 및 V/F 컨버터 설계)

  • Kim, Kwang-Dong;Yim, In-Sung;Byun, Do-Young;Song, Min-Gyu
    • Publications of The Korean Astronomical Society
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    • v.22 no.3
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    • pp.83-87
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    • 2007
  • We designed the Intermediate Frequency(IF) distributor for multi beam backend system and manufactured Voltage to Frequency Converter(VFC) to measure the multi-beam receiver performance. Multi beam receiver has 15 channel receivers and can get 15 spectrums at once. The multi beam receiver has more observation efficiency than single beam receiver. We manufactured the 15 IF distributors to distribute IF signal for Autocorrelation spectrometer that is radio signal processor. Also, we manufactured the VF Converter to test the performance measurement of receiver for Korea VLBI Network(KVN) system which is under-construct in Seoul, Ulsan and Jeju. As a result of performance measurement, we could obtain linearity of 99.4% on the input power vs output frequency and measured the operating range of input frequency.

Development of the Side Scan Sonar Using the Multi-beam Sensors : Sensor Design (멀티빔 센서를 이용한 사이드 스캔 소나 개발 : 센서 설계)

  • Chang, Yu-Shin;Keh, Joong-Eup;Jo, Heung-Gi;Lee, Man-Hyung
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.10
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    • pp.581-586
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    • 2005
  • The multi-beam side scan sonar system uses the towfish installed sonars, it is an equipment that search images of the bottom surface of the sea in real time. It is a typical equipment that is related to a sea investigation such as a geological survey, seabed communication cable and power line cable placing repair investigation, fish breeding ground investigation, sea purification, relic and mineral investigation, and mine and submarine search. Recently, it is used to sea purification and geological survey that require information of the correct surface of the seabed. Therefore, this research develops multi-beam sensors for a side scan sonar that supply various information with the fast scan speed and correct high resolution that is not a simple underwater investigation equipment.

An Analysis of Baseband Packet Switching Scheme for Multi-Beam Satellite Communications (다중빔 위성통신을 위한 기저대역 패킷 스위칭 기법 분석)

  • Kim, Won-Ho;Lee, Yong-Min;Ku, Bon-Jun
    • Journal of Satellite, Information and Communications
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    • v.5 no.2
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    • pp.97-103
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    • 2010
  • In this paper, we present an efficient design scheme based on analysis of design requirements and considerations of baseband packet switch for S-band satellite/terrestrial hybrid multi-beam satellite communication systems. To establish design requirements and considerations, we analyze required functions of baseband packet switch, specifications of multi-beam satellite communications, communication services and performance requirements. And also we analyze and compare conventional layer-2 and layer-3 satellite baseband packet switching techniques, packet switching protocols and packet switch architectures, to apply from analyzed results. Finally, we propose a hardware design scheme of MPEG based layer-2 baseband packet switch using analyzed results.

Applicability Evaluation of Multi Beam Echo Sounder for Inland Water (다중빔 음향측심기의 내수면 적용성 평가)

  • Jung, Jin Woo;Cho, Kwang Hee;Hong, Seung Seo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.6
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    • pp.629-639
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    • 2018
  • In this study, the application of the single beam echosounder and multi beam echosounder was analyzed for the Youngsan river, from the Juksanbo to the Juksan bridge, length of 840m, width 230m and area $0.16km^2$. A single beam echosounder and a multi beam echosounder are mounted on an USV (Unmanned Surface Vessel), and each data is acquired. Then, TIN (Triangular Irregular Network) is created and the grid depth of 10m intervals is extracted. The grid depth of the single beam echo sounder and the grid depth of the multi beam echo sounder were overlapped to compare the two data. As a result of analysis using 5,024 data, the mean depth difference was 0.0319m and the standard deviation was 2.4095m. The river bed shape was similar to each other. If the multi-beam echo sounder is regarded as the standard, the volume difference of the stream is $161,882m^3$. With a multi-beam echo sounder installed, the operating distance increased by approximately 55% to 4595.85m, and the operating time increased by approximately 59% to approximately 47%.