• Title/Summary/Keyword: 펄스도플러 모드

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Improvements of Pulse Doppler Gap Filling Algorithms for Portable Medical Ultrasound Imaging System (휴대용 초음파진단기를 위한 펄스 도플러 갭 필링 알고리즘의 개선)

  • Bae, MooHo;An, Hyung-Jun
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.8
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    • pp.580-589
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    • 2012
  • In this paper, we studied on Doppler gap-filling algorithms suitable for a portable or low-cost medical ultrasound imaging system, and as a result, found out algorithms based on mirroring or autoregressive model. Moreover, controlling the computational demand in the proper range, we improved the performances of these algorithms by solving their problems. Effectiveness of these modified algorithms is verified by computer simulations and experiments which used artificially generated Doppler signals and Doppler data acquired from human body through an actual ultrasound system.

A New Method for Extending Doppler Mean Frequency in Ultrasonic Imaging Systems (초음파 영상 시스템에서 새로운 도플러 평균주파수 확장 방법)

  • Kwon, Sung-Jae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1047-1056
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    • 2007
  • Basically, an ultrasonic imaging system has two fundamental imaging modes available. One is the B-mode imaging modality which provides an image of reflection coefficient, and the other is the Doppler color flow mode that maps blood flow inside the human heart and blood vessels. This paper presents a new method of detecting and compensating for aliasing that occurs when the Doppler frequency exceeds one-half of the pulse-repetition frequency (PRF). Its validity is shown by computer simulation. The new method not only extends the measurable Doppler frequency, but also helps to reduce the effect of noise. The results show that the aliasing can be compensated for correctly fur signal-to-noise ratios down to 20 dB.

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Study on Multi-Mode Monopulse Signal Processing System Providing Optimal Time Delay under High Doppler Condition (고속 도플러 편이 환경에서 최적 시간지연을 갖는 다중모드 모노펄스 신호처리에 관한 연구)

  • Lee, Jaemoon;Lim, Jaesung;Ahn, Huisoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.5
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    • pp.582-589
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    • 2016
  • Multi-mode monopulse system is widely used for satellite terminal like UAV because of high tracking accuracy and low size/weight profile. In order to calculate tracking error, Multi-mode monopulse system utilizes high-order mode signal, and it should have enough C/N(carrier to noise) level therefore tracking system needs narrow band filtering of received satellite beacon signal as much as possible. However, UAV suffers for beacon frequency drift derived from Doppler effect due to satellite figure 8 movement and UAV maneuvering. Therefore wideband signal processing needs to be considered in advance for exact doppler compensation and consequent time delay. In this paper, we propose the multi-stage Digital Signal processing system for beacon signal, which could minimize the signal delay under high Doppler and low C/N condition.

Airborne Pulsed Doppler Radar Development (비행체 탑재 펄스 도플러 레이다 시험모델 개발)

  • Kwag, Young-Kil;Choi, Min-Su;Bae, Jae-Hoon;Jeon, In-Pyung;Yang, Ju-Yoel
    • Journal of Advanced Navigation Technology
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    • v.10 no.2
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    • pp.173-180
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    • 2006
  • An airborne radar is an essential aviation electronic system of the aircraft to perform various missions in all weather environments. This paper presents the design, development, and test results of the multi-mode pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRU units, which include ANTU(Antenna Unit), TRU(Tx Rx Unit), RSDU(Radar Signal & Data Processing Unit) and DISU(Display Unit). The developed technologies include the TACCAR processor, planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, DSP based Doppler FFT filtering, adaptive CFAR, IMU, and tracking capability. The design performance of the developed radar system is verified through various helicopter-borne field tests including MTD (Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.

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Analysis of SAR Processing Performances with FJB Waveforms (FJB 파형을 이용한 SAR 영상 생성 기법 분석)

  • Kim, Eun-Hee;Roh, Ji-Eun;Park, Joon-Yong;Kim, Soo-Bum
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.3
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    • pp.195-207
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    • 2017
  • Recently, the SAR-GMTI mode is becoming increasingly essential in airborne radar systems. While SAR requires wideband waveforms for high resolution imaging, GMTI requires narrowband waveforms for doppler processing, which makes general LFM waveforms difficult to use for SAR-GMTI. This paper analyses the FJB(Frequency Jump Burst) waveform, which is studied for the SAR-GMTI waveform, and presents the method for the pulse compression and SAR image formation using FJB waveforms. Simulation results show that there is little difference in performances between the FJB waveform and the LFM waveform.

X-band Pulsed Doppler Radar Development for Helicopter (헬기 탑재 X-밴드 펄스 도플러 레이다 시험 개발)

  • Kwag Young-Kil;Choi Min-Su;Bae Jae-Hoon;Jeon In-Pyung;Hwang Kwang-Yun;Yang Joo-Yoel;Kim Do-Heon;Kang Jung-Wan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.8 s.111
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    • pp.773-787
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    • 2006
  • An airborne radar is an essential aviation electronic system for the aircraft to perform various civil and/or military missions in all weather environments. This paper presents the design, development, and test results of the multi-mode X-band pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRUs(Line-Replacement Unit), which include antenna unit, transmitter and receiver unit, radar signal & data processing unit and display Unit. The developed core technologies include the planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, MTI, DSP based Doppler FFT filter, adaptive CFAR, moving clutter compensation, platform motion stabilizer, and tracking capability. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test as well as helicopter-borne field tests including MTD(Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.

A Study of Transceiver System for Ka-band Road Watch Radar (Ka 대역 도로 감시 레이더를 위한 송수신 시스템 연구)

  • Shin, Seung-Ha;Jun, Gye-Suk
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.11A
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    • pp.933-940
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    • 2011
  • In this paper, Ka-band transceiver for road watch radar system is designed and fabricated. The transceiver for road watch radar system is composed of waveform generator, frequency generator. IF transceiver and RF up/down converter. The transceiver especially has 3 different waveform mode for target detection range. The transceiver had over 150 MHz bandwidth in Ka-band and 22 dBm output power. The receiver gain and noise figure was 30 dB and 4 dB respectively. The receive dynamic range was 65.28dB and amplitude imbalance and phase imbalance of I/Q channel was 0.3 dB and 1.8 degree respectively. The transceiver meets the required electrical performances through the individual tests.

레이다와 전파신호처리 기술(I)

  • 곽영길
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.5 no.1
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    • pp.100-110
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    • 1994
  • 레이다 신호는 대표적인 전자파 신호로서 주변환경에 따라 시간, 주파수, 공간 영역에서 고유한 신호특성을 가지고 있으며, 신호처리 기법도 다양하다. 본 논문에서는 먼저 레이다를 위한 전파 신호처리 의정의와 필요성을 언급한뒤, 레이다 신호환경 특성을 살펴보고 신호처리를 위한 신호의 시간 및 스펙트럼 특성에 대해 기술하였다. 그리고, 신호특성에 적합한 신호처리기의 구현을 위해 레이다 신호처리에 관 련된 주요 기법에 대해 개괄적으로 설명하였다. 레이다 신호처리 분야는 일반적으로 잘 알려진 음성이 나 영상신호처리 분야와 달리 고유한 알고리듬과 구조가 요구된다. 신호처리기법으로서 레이다 파형설 계, 해상도 모호성, 펄스압축, 클러터제거, 도플러처리, 일정오경보탐지, 클러터 지도, 표적군 형성/ 추출, 표적식별, 레이다영상기법, 적응배열처리 등에 관해 개괄적으로 설명하였다. 레이다 선호처리 기술은 "스마트"한 레이다를 위한 두뇌 역할을 하기때문에 그 필요성과 중요성이 증가하고 있다. 그러나, 고속, 대용량의 신호를 주어진 빔 주사시간동안에 실시간으로 처리하여 표적 정보를 추출해야 하기 때문에 아직도 상용 프로세서의 속도 한계내에서 알고리듬의 수행에 다소 제약을 받고 있으나, 최근 디지탈 신호처리 전용의 고속 칩의 출현으로 많은 발전을 가져오고 있다. 끝으로, 향후 레이다 신호처리 발전 추세와 응용분야에 대해 살펴보았다. 응용분야는 군수 및 민수용의 겸용 파급효과가 매우 크고, 군용의 대공탐색 및 조기경보, 전장감시뿐만 아니라 전투기 탑재용으로 필수적이며, 특히 민수용의 공 항, 항공기, 선박, 위성 등 매우 다양하다. 최근 발전추세에 따른 기술로서 다중모드 신호처리, 고집적 회로기술, 적응배열, 디지탈 빔형성, 적응성, 고분해능 및 방향성, 표적식별, 다차원 신호처리에 대해 언급 하였다.

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