• 융합신호처리학회논문지
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• 제19권2호
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• pp.68-76
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• 2018

본 논문에서는 대전상관기의 다중 편파 관측데이터의 상관처리 방법에 대해 기술한다. VLBI 관측에는 천체의 종류에 따라 단일 또는 다중 편파 관측이 있는데, 천체의 특성을 잘 관찰하기 위해 편파관측을 수행한다. 그리고 천체를 관측하는 동안 관측장치에 포함된 지연값과 천체의 변동원인을 확인하기 위해서도 편파관측을 수행한다. 대전상관기의 편파관측 데이터의 상관처리는 각 안테나 유닛에 입력되는 데이터를 출력하는 동기재생처리장치의 OCTAVIA에서 출력비트 선택 기능을 활용하여 비트를 변환하고, 이때 데이터 스트림(Stream)의 순서가 변경되며, 대전상관기의 입력은 기존의 스트림 번호는 동일하게 설정하여 상관처리를 수행하면 편파상관처리를 할 수 있는 구성을 제안하였다. 편파상관처리를 위해 관측한 시험데이터를 대상으로 상관처리를 수행하였으며, 본 연구에서 제안한 대전상관기의 편파상관처리 방법이 유효하게 동작하고 있음을 실험을 통하여 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.94-97
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• 1987

An acousto optic correlator system for performing real-time correlation of two signals is constructed. It uses AOD is described. The statistical analysis for correlator's output SNR is presented and experimental procedure for implemention of this technique are result shown. Since the correlation intergration is performed in time rather than space, the SNR of this system can be greatly improved.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2002년도 한국우주과학회보 제11권1호
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• pp.38.1-38
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• 2002

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.37.2-37.2
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• 2008

Korea-Japan Joint VLBI Correlator (KJJVC), to be used for Korean VLBI Network (KVN) in Korea Astronomy & Space Science Institute (KASI), is a high-speed calculator that outputs the correlation results in the maximum speed of 1.4GB/sec.To receive and record this data keeping up with this speed and with no loss, the design of the software running on the data archive system for receving and recording the output data from the correlator is very important. But, the simple kind of programming using just single thread that receives data from network and records it by turns, can cause a bottleneck effect while processing high speed data and a probable data loss, and cannot utilize the merit of hardwares supporting multi core or hyper threading, or operating systems supporting these hardwares. In this talk we summarize the design of the data transfer software for KJJVC and high speed, large capacity data archive system using general socket programming and multi threading techniques, and the pre-BMT(Bench Marking Test) results from the tests of the storage product providers' proposals using this software.

• Journal of Positioning, Navigation, and Timing
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• 제2권1호
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• pp.1-8
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• 2013

A signal system for improving the code acquisition complexity of Global Navigation Satellite System (GNSS) receiver is proposed and the receiving correlator scheme is presented accordingly. The proposed signal system is a hierarchical code type with a duplexing configuration which consists of the Zadoff-Chu (ZC) code having a good auto-correlation characteristic and the Pseudo Random Noise (PRN) code for distinguishing satellites. The receiving correlator has the scheme that consists of the primary correlator for the ZC code and the secondary correlator which uses the PRN code for the primary correlation results. The simulation results of code acquisition using the receiving correlator of the proposed signal system show that the proposed signal scheme improves the complexity of GNSS receiver and has the code acquisition performance comparable to the existing GNSS signal system using Coarse/Acquisition (C/A) code.

• 천문학회보
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• 제30권2호
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• pp.65.2-65.2
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• 2005

• 한국통신학회논문지
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• 제11권5호
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• pp.360-369
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• 1986

두 신호의 상관을 실시간으로 처리하는 AOTIC(Acoustoopic Time Intergrating Correlator) 시스템을 구성하였다. 이 시스템은 AOD(Acoustoopic Device)와 CCD(Charge Coupled Device)를 사용한다. 신호의 상관을 얻는 AO 기술을 다룬다. 상관기의 출력 SNR에 대한 통계적인 해석을 제시하고 AO기술에 의한 실험의 결과를 보여준다. 상관적분이 공간상보다는 시간상으로 되므로 시스템의 SNR을 크게 개선시킬 수 있음을 알 수 있었다.

• 천문학논총
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• 제23권2호
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• pp.73-90
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• 2008

A software simulator is developed for verifying the VLBI Correlation Subsystem (VCS) trial product hardware. This software simulator includes the delay tracking, fringe rotation, bit-jump, FFT analysis, re-quantization, and auto/cross-correlation functions so as to confirm the function of the VCS trial product hardware. To verify the effectiveness of the developed software simulator, we carried out experiments using the simulation data which is a mixed signal with white noise and tone signal generated by software. We confirmed that the performance of this software simulator is similar as that of the hardware system. In case of spectral analysis and re-quantization experiment, a serious problem of the VCS hardware, which is not enough for expressing the data stream of FFT results specified in VCS hardware specification, was found by this software simulator. Through the experiments, the performance of software simulator was verified to be efficient. In future, we will improve and modify the function of software simulator to be used as a software correlator of Korea-Japan Joint VLBI Correlator (KJJVC).

• 천문학논총
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• 제27권1호
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• pp.1-16
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• 2012

In this paper, we describe the installation of VLBI Correlation Subsystem (VCS) main product and its performance at the Korea-Japan Correlation Center (KJCC). The VCS main product was installed at KJCC in August 2009. For the overall performance evaluation of VCS, playbacks, Raw VLBI Data Buffer (RVDB) system, and Data Archive (DA) system were installed together. The VCS main product was connected between RVDB and DA, and the correlation results were put into the DA to confirm the normal operation of VCS 16 station mode configuration. The evaluation test was first performed with 4 station mode, same as the factory test of VCS main product. Based on the results of 4 station mode, the same evaluation test was conducted for 16 station mode of VCS. We found that the correlation results of VCS were almost similarly compared to those of the Mitaka FX Correlator. Through the test results, we confirmed that the problems such as spectrum errors, delay parameter processing module and field programmable gate array errors in antenna unit, which were generated at the factory test of VCS main product, were clearly solved. And we verified the performance and connectivity of VCS by obtaining the expected correlation results and we also confirmed that the performance of VCS was sufficient for real VLBI observation data in both 4 and 16 station modes.

• 한국정보통신학회논문지
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• 제17권1호
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• pp.190-196
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• 2013

커브형 집적 영상 기술은 렌즈 배열을 이용하여 3D 영상을 공간에 쉽게 표현할 수 있는 기술이며, 넓은 관측각을 제공한다. 본 논문에서는 커브형 집적 영상에서 물체의 인식 향상을 위하여 다이렉트 픽셀 매핑 (DPM) 방법 기반의 비선형 상관기를 제안한다. 제안하는 비선형 상관기는 커브형 집적 영상 시스템에서 장애물에 가려진 물체로부터 픽업된 요소 영상을 DPM 방법을 통하여 해상도가 향상된 새로운 요소 영상을 생성한다. 새로운 생성된 요소 영상을 사용하여 복원한 3D 영상들과 참조 영상간의 비선형 상호상관을 이용하여 3D 물체의 인식 성능 향상시킨다. 제안된 방법의 유용함을 보이기 위하여 기초적인 상관 관계 실험을 수행하고 기존의 방법과의 비교 결과를 보고한다.