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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Advanced Navigation Technology
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Journal DOI :
The Korea Navigation Institute
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Volume & Issues
Volume 9, Issue 2 - Dec 2005
Volume 9, Issue 1 - Jun 2005
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TSK Type Fuzzy Controller Design for Altitude Control of an Unmanned Helicopter
Kim, Jong-Kwon ; Seong, Ki-Jun ; Cho, Kyeum-Rae ; Jang, Chul-Soon ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 87~92
An altitude control using a fuzzy controller was performed for a series of research for autonomous flight control of industrial unmanned helicopters. The 3m class gasoline engined unmanned helicopter was designed, and using the designed specifications, Takagi-Sugeno-Kang type fuzzy controller was designed. The input membership functions were generated using target altitude, altitude error and velocity of unmanned helicopter. With these membership functions, the control inputs for altitude control were calculated. These control input signal can control the main rotor's pitch and determine the velocity and altitude of the unmanned helicopter. Also, the altitude control performance of the designed fuzzy controller was evaluated by computer simulations
Access Point Interface Configuration using Radio over Fiber for the WIBRO System
Song, Ju-Bin ; Kim, Young-Il ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 93~102
This paper presents an interface configuration between Access Point(AP) and Radio Over Fiber (ROF) transceiver for the wireless internet system. The wireless internet could provides 60km/h mobility and 50Mbps IP based data services for each mobile terminal. Thus, cost effective cell infrastructure is inevitably required. This paper suggests an interface configuration between AP and passive integrated picocell(PIP) involving ROF links. Nonlinear characteristics of ROF link using a typical FP transceiver are measured for wireless internet applications.
Design of Broadband Hybrid Mixer using Dual-Gate FET
Jin, Zhe-Jun ; Lee, Kang-Ho ; Koo, Kyung-Heon ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 103~109
This paper presents the design of a broadband hybrid mixer using dual-gate FET topology with a low-pass filter which improves return loss of output to isolate RF and LO signal. The low-pass filter shows the isolation with RF and LO signal of better than 40 dBc from 1.5 GHz to 5.5 GHz. The dual-gate mixer which has been designed by using cascade topology operates when the lower FET is biased in linear region and the upper FET is in saturation region. The input matching circuit has been designed to have conversion gain from 1.5 GHz to 5.5 GHz. The designed mixer with low-pass filter shows the conversion gain of better than 7 dB from 1.5 GHz to 5.5 GHz at the low LO power level of 0 dBm with the fixed IF frequency of 21.4 MHz.
Bit Error Rate Dependence on Amplifier Spacing in Long-Haul Optical Transmission System with Mid-Span Spectral Inversion
Lee, Seong-Real ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 109~120
In this paper, bit error rate (BER) characteristics, sensitivity and minimum allowable launching power are numerically investigated as a function of amplifier spacing that consisted of 1,200 km WDM systems with MSSI method. It is conformed that the sensitivity and minimum allowable launching power are gradually degraded as amplifier spacings are gradually expanded, but those are not largely affected by modulation format. The sensitivity of RZ transmission system is smaller than that of NRZ transmission system, but minimum allowable launching power of NRZ transmission system is smaller than that of RZ transmission system. And, it is confirmed that the best amplifier spacing in NRZ and RZ transmission system is less than 50 km, because the sensitivity and minimum allowable launching power are less affected by fiber dispersion, channel wavelength and pump light power.
A Study on the Design and Realization of the VHF Transmitter for Air Traffic Control
Park, Wook-Ki ; Kang, Suk-Youb ; Park, Hyo-Dal ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 121~130
In this paper, we designed and fabricated the VHF wireless transmitter for air traffic control. Fundamental performance of the investigated wireless transmitter is designed and fabricated to satisfy existing commercial wireless transmitter specification for air traffic control. 25 W and 50 W of output power can be generated by changing the power amplification part only. It is based on transmitting voice communication using AM modulation. Investigated wireless transmitter for air traffic control consists of four module parts: power supply, control, low power transmission and power amplification. We designed 1W transmitter to operate without power amplification part. It can be used properly in a basic component of CNS/ATM.
A Study on the Discrimination of Materials Corrosion States Using the Acoustic Signal Data
Moon, Gun ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 131~139
On this study, I constructed the reflective acoustic signal detecting system using 15MHz acoustic transducer. The most difficult problems discriminating the characteristics of the metal substance are the discriminating the corrosion state and seeking hidden defects by using none destructive testing. For solving these problems, at first, theoretic analysis has been proceeded on the acoustic V(z) characteristics which is very important on discriminating the material characteristics. For application the V(z) theory to discriminating corrosion state, the 100 and 500 won metal coins which are issued on the different years are used as the test samples. The experimental results showed the distinct differences among the coin's acoustic signals accorded to its issued years. I catched the common regulation by analysing the acquisited acoustic signals and convinced this technique to be very useful on corrosion discrimination of the metal substances by none destructive testing and also can be used to inspect on the aeronautical materials for safety navigation.
Performance Analysis of Frequency Offset Compensation and Tracking Algorithms for HDR-WPAN System
Park, Ji-Woo ; Oh, Chang-Heon ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 140~146
In this paper, we proposed the frequency offset compensation algorithm and tracking algorithm which could improve the accumulated phase error for HDR-WPAN system. The proposed frequency offset compensation technique estimated each sample phase error by autocorrelation characteristics of CAZAC sequence, estimated phase error multiple each sample in a symbol, and finally compensated for the frequency offset. After frequency offset compensation using two steps, coarse and fine frequency offset, tracking algorithm have to use to compensate for the accumulated phase error. Because there is no pilot symbol in payload, more phase rotation occurred in received signal constellations due to the accumulated phase error as the payload length increase. Tracking algorithm compensates for a cumulative phase error
between payload data.
Study on Coupling Characteristics between TE
Mode Dielectric Resonator and Coplanar Waveguide Structure
Kim, Jong-Hyuk ; Kim, Ihn S. ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 147~155
In this paper, we propose that three uniform coplanar waveguides(CPWs), such as a conventional, finite grounded(FG), and grounded(G) CPWs, can be coupled with a
mode dielectric resonator(DR) for a parallel resonant characteristic as a microstrip line coupled with the DR. Coupling characteristics have been investigated by placing the DR on a dielectric support above the CPWs and by moving the DR away from the center of a slot of the CPWs to the ground plane. FEM simulation(HFSS) results in terms of S-parameters agree well with measurement results. Finally, unloaded Q values of the DR coupled with the three uniform CPWs are compared with those of the DR coupled with a microstrip line. The comparison shows that the DR coupled with the three CPWs has higher unloaded Qs than that coupled with a microstrip line and that the GCPW case has the highest unloaded Qs.
Performance Evaluation of VHF Digital Link Mode 3 System
Bae, Joong-Won ; Nam, Gi-Wook ; Kwak, Jae-Min ; Park, Ki-Sik ; Cho, Sung-Eon ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 156~163
In this paper, we analyzed the performance of VDL mode 3 system model whose specification is defined by ICAO(International Civil Aviation Organization). For performance evaluation, we obtained BER(Bit Error Rate), transmission delay time, burst retransmission rate and throughput. From the analysis result, we could explicitly define relationships among BER, transmission delay time, throughput and burst restransmission rate. In addition, it became known that V/D retransmission rate and throughput are closely related in down link channel.
Design of High Efficiency Doherty Power Amplifier Using Adaptive Bias Technique for Wibro Applications
Oh, Chung-Gyun ; Choi, Jae-Hong ; Koo, Kyung-Heon ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 164~169
In this paper, the high efficiency Doherty power amplifier using adaptive bias technique has been designed and realized for 2.3GHz Wibro applications. The RF performances of the Doherty power amplifier using adaptive bias technique have been compared with those of a class AB amplifier alone, and conventional Doherty amplifier. The Maximum PAE of designed Doherty power amplifier with adaptive bias technique has been 36.6% at 34.0dBm output power. The proposed Doherty power amplifier showed an improvement 1dB at output power and 7.6% PAE than a class AB amplifier alone.
Human Visual System Based Adaptive Watermarking in Frequency Domain
Park, Ki-Hong ; Yoon, Byung-Min ; Kim, Yoon-Ho ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 170~176
In this paper, we proposed watermarking algorithm based on wavelet transform. Discrete wavelet transform is involved to calculate additive energy strength. Considering imperceptibility, after computing contrast and texture sensitivity in gray-level image, we inserted watermark with variable weight due to the feature of coefficient block. Consequently, applying human visual system, the experimental results showed that the proposed algorithm satisfied the properties of robustness and imperceptibility that are the major conditions of watermarking.
Analysis on the Interference from HAPS Airship into P-MP FWA System
Choi, Mun-Hwan ; Ham, Hyoung-Il ; Kang, Young-Heung ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 177~184
In this paper, we have analyzed the effects of the interference from HAPS airship stations to P-MP FWA base station and to P-MP FWA terminal station, using more detail parameters such as a new interference model, a realistic HAPS scenario, practical antenna patterns for both HAPS system and FWA system. The analysis results show that, in the case of interference from HAPS AS into the P-MP FWA BS, compatibility between two systems can be obtained by using a sectored BS antenna with the boresight directed away from the nadir. However, in the case of Interference from HAPS AS into the P-MP FWA TS, the two systems cannot operate effectively in the same bands unless the separation distance is guranteed and/or some form of interference mitigation technique is employed such as dynamic channel allocation.
Analysis of Handling Qualities for Smart Unmanned Aerial Vehicle in Helicopter Flight Mode
Lee, Jang-Ho ; Kim, Eung-Tai ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 185~192
The aim of this paper is to analyze handling qualities of tiltrotor aircraft(TR-S4) in helicopter flight mode including hovering and forward flight. Analysis of handling qualities is composed of aircraft response to control inputs that effect on stability and controllability. In short term response analysis, bandwidth is the critical parameter for small amplitude motions since it relates to the ability of a pilot to crisply start and stop maneuver. The handling qualities of TR-S4 in helicopter mode are analyzed with a SAS and an attitude controller and are satisfied level 1 in almost criteria with simulation of TR-S4 6-DOF nonlinear model.
A Study on the Power Allocation for AMC Scheme in OFDMA System
Kim, Dong-Cheol ; Shin, Hyun-Joon ; Hong, Een-Kee ;
The Journal of Advanced Navigation Technology, volume 9, issue 2, 2005, Pages 192~199
Adaptive Modulation & Coding (AMC) is the method of varying the modulation and coding scheme for the changeable wireless channel environment. WiBro use AMC method because it has a very large variation caused by mobility interference and other cell interference. In this paper, we will compare and analysis the method of selecting the optimum MCS level for the efficiently use of mobile power consumption.