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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Advanced Navigation Technology
Journal Basic Information
Journal DOI :
The Korea Navigation Institute
Editor in Chief :
Volume & Issues
Volume 6, Issue 4 - Dec 2002
Volume 6, Issue 3 - Nov 2002
Volume 6, Issue 2 - Aug 2002
Volume 6, Issue 1 - Jun 2002
Selecting the target year
Enhanced Resolution of Spatially Close Incoherent Sources using Virtually Expanded Arrays
Kim, Young-Su ; Kang, Heung-Yong ; Kim, Chang-Joo ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 181~187
In this paper, we propose a resolution enhancement method for estimating direction-of-arrival(DOA) of narrowband incoherent signals incident on a general array. The resolution of DOA algorithm is dependent on the aperture size of antenna array. But it is very impractical to increase the physical size of antenna array in real environment. We propose the method that improves resolution performance by virtually expanding the sensor spacing of original antenna array and then averaging the spatial spectrum of each virtual array which has a different aperture size. Superior resolution capabilities achieved with this method are shown by simulation results in comparison with the standard MUSIC for incoherent signals incident on a uniform circular array.
The Design of Dual Phase LNB for DBS Receiving
Lim, Yun-Doo ; Ko, Bong-Jin ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 188~194
DBS is utilized as very useful media in information-oriented society because it covers wide service area and provide high quality services. But DBS needs skill that can receive DBS signal at move. In this paper, it is considered a development of a device to receive DBS and design of a low noise downconverter that use tracking antenna to receive DBS at mobiles unit and ships which navigate in Korea peninsula coast. The structure of dual phase LNB is composed of LNA, BPF, oscillator, mixer, and IF amplifier. And for the position tracking, two input-output phase performed in phase. Measured results showed good performance that with respect to input signal 11.7 GHz~12.2 GHz, noise figure is 0.87 dBmax and conversion gain 62 dB, temperature characterization
kHz in respect to - 30 to
, and phase noise -101 dBc/Hz in respect to offset 100 kHz.
Study on the Passive IMD Improvement of RF DIN Connectors
Ko, Yun-Sun ; Chung, Jae-Pil ; Oh, Chang-Heon ; Shin, Dong-Uk ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 195~202
Recently, as the range of mobile communication services is extended, the interference between adjacent base-stations is increased. Nowdays, one of the important factors causing interference is IMD (Inter-Modulation Distortion) problems. Not only active IMD but also passive IMD effects must be considered to design a CDMA system. In this study, we design and implement 7/16" DIN connectors which have a various intensity of surface illumination, thickness and quality of plating material to analyze the effects of PIMD. And propose the methods for improving the PIMD characteristics: First, it is more profitable to use the metal which has good intensity of surface illumination where most of all electric currents passes through it. Secondly, we should plate metals more than
for RF energy enough to propagate in a medium. Thirdly, it is necessary to select a metal having high conductivity and specific heat to protect the aging phenomenon of plate material. And it is required to develop a new plating material to replace the current materials, such as the alloy of three components for cost reduction. We have to know that the plate which has intensity of surface illumination 6 S and the thickness of plating material
satisfy the domestic PIMD specification (KTF) -150 dBc, regardless of the plate material in case of 7/16" DIN connector.
Performance Improvement of IEEE 802.11a WLAN System by Improved Channel Estimation Scheme using Long/Short Training Symbol
Kwak, Jae-Min ; Jung, Hae-Won ; Cho, Sung-Joon ; Lee, Hyeong-Ho ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 203~210
In this paper, the BER performance of IEEE 802.11a OFDM WLAN system is obtained by simulation and it is shown that the proposed modified channel estimation algorithm improves the channel estimation performance of the system. The wireless channel used in channel simulation includes AWGN and delay spread channel implemented by TDL model. At first, the performance of OFDM WLAN system according to data rate and coding rate defined in standard is evaluated in AWGN channel. Then, imperfect channel estimation in indoor wireless channel is considered. After the performance of conventional channel estimation scheme using only two long training symbols is evaluated, and that of proposed modified channel estimation scheme using additional 8 short training symbol is compared with it. From the simulation results, it is shown that modified channel estimation scheme provides reduced channel estimation error and improves the channel estimation performance due to noise averaging effect with the same preamble format as defined in specification.
The Utility of Satellite Sensors of the Missile Defense Systems
Park, Chul-Hyun ; Kwon, Yang-Soo ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 211~222
This paper describes the utility of satellite sensors of the missile defense system using the estimation theory. The inherent flight characteristics of the missiles give the limitations in the response time and the countermeasures. In this point, the early warning and surveillance satellites are important. Using the Extended Kalman Filter, it is analysed LPU and MLU in DSP and SBIRS satellites, and presented the quantitative uncertainties of state estimates of non-rotational DSP compare to the rotating one.
Evaluation of Bit Error Rate of a Long-Haul Optical Transmission System adopted the Mid-Span Spectral Inversion Method
Lee, Seong-Real ; Kim, Nam-Sung ; Bang, Hyo-Chang ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 223~230
In this paper, we induced that the noise powers and bit error rate of direct detection receiver taking account of ISI (intersymbol interference) in the 2,000 km optical transmission system. And we evaluated the sensitivity in the vrious bit rate system. We verified that the proposed calculation method is applicable to the exact optical system. And we confirmed that the signal distortion due to both chromatic dispersion and nonlinear effects compensated by using of MSSI (Mid-Span Spectral Inversion) method, and yet the sensitivity of a higher bit rate system is reduced, because of the increase of ISI and then the decrease of the average receiving power, compared with a the lower bit rate system.
Comparison of Tracking Performace for a Maneuvering Target under the Variation of Maneuver Detection Thresholds
Park, Je-Hong ; Lee, Woo-Joo ; Lim, Sang-Seok ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 231~240
For a long time target maneuvers in tracking problem have been a difficult task to handle. In order to solve this problems. there have been various tracking techniques. In the development of a tracking filter for a maneuvering target, maneuver detection threshold plays a key role. However, no study of filter performance the varying maneuver detection threshold has been carried out so far. Instead, the maneuver detection have been chosen empirically. In this paper, the effect of detection threshold selection on the performance of the tracking filters was considered and the relationships between maneuvers and the detection threshold have been analyzed by simulation.
Performace Analysis of Channel Presumption Technique with STTC Applied to IEEE 802.11a System
Kweon, Soon-Nyu ; Lee, Yun-Hyun ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 241~250
This paper presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia OFDM system. The presented method is a comparative analysis between a case where parameter
for time average is 0.3, 1 with consideration of channel presumption with two types of rms delayed spread, which is 50nsec, 150nsec, for the performance analysis of STTC(Space-Time Trellis Code) using time-space ciphering method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of 1.0 dB in
was 0.3 than using only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.
Characteristic Improvement & Design of Dual Polarization Wideband Single Element Antenna for IMT-2000 Base Station
Jang, Won-Ho ; Park, Joo-Sung ; Tae, Jae-Hoon ; Lee, Yun-Hyun ;
The Journal of Advanced Navigation Technology, volume 6, issue 3, 2002, Pages 251~257
Design and characteristic improvement of existing folded dipole antenna is presented to adopt W-CDMA(1.885~2.170 GHz) wideband antenna radiators. The antenna structure has +/- 45 degrees dual polarization. In order to overcome the narrow bandwidth and low gain characteristic typical of the microstrip antenna, double layered structure was employed. The antenna achieved below - 20 dB reflection coefficients each ports, - 20 dB of port isolation, above 7 dBi of gain, providing evidence that the proposed design can be used in the W-CDMA service frequency band antenna.