Implementation of the COHO Unit for Phase-locking of Radar
조태복Tae Bok Cho,신혜진Hye Jin Shin,이택경Taek Kyung Lee
3(1) 1-12, 1999
조태복Tae Bok Cho,신혜진Hye Jin Shin,이택경Taek Kyung Lee
DOI: JANT Vol.3(No.1) 1-12, 1999
For the phase measurement of radar signal in the coherent-on-receiver system, the COHO(Coherent Oscillator) generates the signal which locks to the phase of the transmit pulse. In this paper, COHO unit is developed to generate 60MHz phaese-locked signal. ILO(Injection Locking Oscillator) locks to the sample of the transmit pulse. Gate circuit, ILO. buffer amplifier, and pulse generator are designed and implemented.
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Precise Survey of Dokaebi Road Using CDGPS
기창돈Chang Don Kee,김정한Jeong Han Kim
3(1) 13-19, 1999
기창돈Chang Don Kee,김정한Jeong Han Kim
DOI: JANT Vol.3(No.1) 13-19, 1999
Using GPS carrier phase whose cycle ambiguities are resolved, it is possible to perform precise survey requiring centimeter-level positioning accuracy. Because of an optical illusion, we cannot recognize the exact slope of Dokaebi Road. In this paper, we performed kinematic survey experiments in order to calculate the exact slope of Dokaebi Road with high positioning accuracy of CDGPS. By post-processing experimental data using CDGPS, it was possible to generate the exact vertical trajectory of Dokaebi Road with centimeter-level accuracy.
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Interference Analysis of TV Signal Affected by Flights of An Airplane around KimPo International Airport Circumference
이찬주Chan Joo Lee,김봉철Bong Cheol Kim,조성준Sung Joon Cho
3(1) 20-31, 1999
이찬주Chan Joo Lee,김봉철Bong Cheol Kim,조성준Sung Joon Cho
DOI: JANT Vol.3(No.1) 20-31, 1999
In this paper, we have chosen KimPo International Airport as an area for estimating the flutter interference, in order to analyze the flutter interference, The field test at 25 points around KimPo International Airport and the simulation have been performed for estimating the flutter interference. We consider the received power of a direct wave, the height of an antenna, the ERP of a transmitting point, transmit frequency, and the reflection coefficients of an airplane, the transmit/receive point coordinates as estimation functions for the flutter. From the results, we have found that the flutter interference from flights is very serious around the route of flight circumference, and often occurs when the height of an airplane is low, range from 40 to 240m. Besides, the degree of the flutter interference can be changed according to the distance between an airplane and a transmitting point, elevation angle, and the reflecton coefficients of an airplane.
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Sensor Fault Detection and Isolation of a Turbojet Engine Using Neural Network
김종선Jong Sun Kim,이강웅Kang Woong Lee,김진곤Jin Gon Kim,부준홍Joon Hong Boo,유상신Sang Sin Yoo,민성기Seong Ki Min
3(1) 32-43, 1999
김종선Jong Sun Kim,이강웅Kang Woong Lee,김진곤Jin Gon Kim,부준홍Joon Hong Boo,유상신Sang Sin Yoo,민성기Seong Ki Min
DOI: JANT Vol.3(No.1) 32-43, 1999
In this paper, we designed an intelligent fault detection and isolation algorithm for improving reliability of turbojet engine controller. The proposed method uses multilayer neural network to detect and accommodate sensor failure from the functional relationship of dissimilar sensors. Signals of failure sensors are estimated from neural network trained by backpropagation algorithm. Simulation results on the state-space model of a turbojet engine illustrate that the proposed algorithm achieves the desired performance.
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Fuzzy-Inference Control of a PWM Inverter for 400 Hz AC Voltage Regulation
이만희Man Hee Lee,송재익Jae Ik Song,이강웅Kang Woong Lee
3(1) 44-51, 1999
이만희Man Hee Lee,송재익Jae Ik Song,이강웅Kang Woong Lee
DOI: JANT Vol.3(No.1) 44-51, 1999
In this paper we proposed an output voltage regulation scheme of a single-phase PWM inverter used to obtain a 400Hz sinusoidal AC voltage for an aircraft. The fuzzy-inference control scheme is designed to achieve good output voltage tracking in the presence of load change or parameter variations. The PWM gate signals are determined by the fuzzy-inference controller using the error between the reference voltage and the feedback voltage and the derivative of error.
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Analysis of the Linear Amplifier/ADC Interface in a Digital Microwave Receiver
이민혁Min Hyouck Lee,김성곤Sung Gon Kim,최희주Hee Joo Choi,변건식Kun Sik Byon
3(1) 52-59, 1999
이민혁Min Hyouck Lee,김성곤Sung Gon Kim,최희주Hee Joo Choi,변건식Kun Sik Byon
DOI: JANT Vol.3(No.1) 52-59, 1999
Digital microwave wideband receiver including linear amplifier, analog-to-digital converter(ADC) and digital signal processor is able to analyze its performance using sensitivity and dynamic range of system. Determination of gain, third-order intermodulation products and ADC characteristics and design criteria for the linear amplifier chain is essential problem for sensitive and dynamic range. Also, if there are two signals with frequencies very close, digital signal processor must be able to separate the two signals. In this paper, we measured dynamic range as gain was changed and determined gain value for the proper sensitivity and dynamic range and high resolution spectrum estimation was used to separate two close signals.
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A Background Image Generation Method for Image Detector Using Detected Vehicle Information
권영탁Young Tak Kwon,김윤진Yoon Jin Kim,박철홍Chul Hong Park,김희정Hee Jeong Kim,소영성Young Sung Soh
3(1) 60-68, 1999
권영탁Young Tak Kwon,김윤진Yoon Jin Kim,박철홍Chul Hong Park,김희정Hee Jeong Kim,소영성Young Sung Soh
DOI: JANT Vol.3(No.1) 60-68, 1999
In this paper, we propose a new background generation method for image detector for traffic information collection. Conventional methods result in bad performance when there are frequent traffic jams due to heavy traffic. To improve on this, we use high level information from vehicle detection. Only part of the image that is not considered as vehicle is used in background generation. The proposed method finds background more robustly than that of the conventional methods even in the presence of heavy traffic.
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A Study on the Improvement of the Utilization of the Korean Airspace
최영일Young Il Choe
3(1) 69-90, 1999
최영일Young Il Choe
DOI: JANT Vol.3(No.1) 69-90, 1999
The Korean airspace is very much limited, but its users are many. Especially many special using airspaces for military aircraft are formulated within the Taegu Flight Information Region and it is so restricted for civil aircraft to use the military airspaces. However, as the demand of civil air traffic is increasing, positive cooperation among the users of the airspace is needed to cope with the demand and to uplift the utilitation of the Korean airspace. Most of airspace except airways within the FIR are restricted areas, prohibited areas or operation areas for the military purpose. This thesis shows how to improve the utilitation of the Korean airspace and how much economical benefit the suggestion gives.
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