Wideband Chirp Waveform Simulation and Performance Analysis for High Range Resolution Radar Imaging
곽영길 Young Kil Kwag
6(2) 97-103, 2002
곽영길 Young Kil Kwag
DOI: JANT Vol.6(No.2) 97-103, 2002
A recent technology trends in synthetic aperture radar(SAR) requires the ultra high resolution performance in detecting and precisely identifying the targets. In this paper, as a technique for enhancing the radar range resolution, the wideband chirp connection algorithm is presented by stitching the several chirp modules with unit bandwidth based on the linear frequency modulated chirp signal waveform. The principles of the digital chirp signal generation and its architecture for implementation is described with the wideband chirp signal generator, modulator, and demodulator. The performance analysis for the presented algorithm is given with the simulation results.
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Implementation and Test of DGPS Integrity Monitoring System
윤영선 Young Sun Yun , 박성민 Sung Min Park , 기창돈 Chang Don Kee
6(2) 104-112, 2002
윤영선 Young Sun Yun , 박성민 Sung Min Park , 기창돈 Chang Don Kee
DOI: JANT Vol.6(No.2) 104-112, 2002
Nowadays, many countries are interested in using GPS for navigation system of aircrafts, because it has technical and economic benefits. For the GPS based navigation system, the most important thing is reliability of the system. GPS navigation solution is very accurate. But when some faults are raised in the GPS navigation system of an aircraft, if they cannot be detected and alerts are not generated for pilots, the aircraft cannot be safe. So, I implemented an DGPS integrity monitoring system that detects faults of measurements and exclude the fault measurement from the satellite constellation used for calculation a navigation solution. This paper introduces `the Least Square Residual Method` used to detect fault of measurements and the implemented real time integrity monitoring system using DGPS. To test the system, I perated the system under many different conditions. And from analysis of the data recorded, I could conclude that when the number of visible satellites was enough to detect faults, the system could detect the faults of measurements perfectly, isolate and exclude the fault measurement well. But for more reliable system, the measurement errors must be estimated more accurately and integrations of GPS and other instruments must be developed.
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Internal GPS Antenna for Mobile Phone
황재호 Jae Ho Hwang
6(2) 113-118, 2002
황재호 Jae Ho Hwang
DOI: JANT Vol.6(No.2) 113-118, 2002
In this paper, an internal GPS antenna for mobile phones is designed and fabricated. For the miniaturization of the antenna, high permittivity dielectric substrate(ε_r = 90) and small ground plane (13 mm × 13 mm) are used. To increase the receive gain, the antenna is composed with LNA(Low Noise Amplifier). Results of the manufactured antenna(13 mm ×13 mm×8 mm) show that the maximum antenna gain is about 12 dBi, the axial ratio is less than 3 dB, and the current consumption of LNA is less than 4 mA.
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Performance Analysis of the Turning Acceleration Estimator, Input Estimation and Variable Dimension Filters for Tracking Maneuvers
최성원 Sung Won Choi , 임상석 Sang Seok Lim
6(2) 119-129, 2002
최성원 Sung Won Choi , 임상석 Sang Seok Lim
DOI: JANT Vol.6(No.2) 119-129, 2002
Maneuvering targets are difficult to track for the Kalman filter since the target model of tracking filter might not fit the real target trajectory and the statistical characteristics of the target maneuver are unknown in advance. In order to track such a highly maneuvering target. several schemes have been proposed and improved the tracking performance in some extent. Among those tracking schemes the Input Estimation(IE). Variable Dimension(VD) and Turning Acceleration Estimator(TAE) became popular. However, so far their tracking performances were analyzed individually and were not compared. In this paper, the tracking performances of the typical IE, VD and TAE schemes for a maneuvering target are compared. Monte-Carlo Simulations for three maneuvering profiles are carried out and the results are analyzed towards practical applications.
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Optimum and Sub-optimum Decoding Methods of Space-Time Trellis Coded Code Division Multiple Access Systems
기영민 Young Min Ki , 김동구 Dong Ku Kim
6(2) 130-137, 2002
기영민 Young Min Ki , 김동구 Dong Ku Kim
DOI: JANT Vol.6(No.2) 130-137, 2002
We present Space-Time Trellis Coded Code Division Multiple Access systems. which maintain the full diversity and coding gain of Space-Time Trellis Codes (STTC) and have the immunity to performance degradation caused by multipath fading. These STTC CDMA systems are constructed by adding the spreading and despreading processes of PN codes to STTC systems. In multipath fading channels, delay spreaded signals are detected and combined. then decoded. According to the combining and decoding methods. there are four decoding methods. There are optimum ML decoding without combining. adding multipath signals in each receive antenna before decoding. combining multipath signals in each antenna before decoding. and combining all received signals before decoding. Performance of these methods is proportional to complexity. Besides. all methods are shown to compensate the irreducible error rate which appears in multipath fading channels.
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An Efficient Adaptive Polarization-Space-Time Domain Radar Target Detection Algorithm
양연실 Yeon Sil Yang , 이상호 Sang Ho Lee , 윤상식 Sang Sik Yoon , 박형래 Hyung Rae Park
6(2) 138-150, 2002
양연실 Yeon Sil Yang , 이상호 Sang Ho Lee , 윤상식 Sang Sik Yoon , 박형래 Hyung Rae Park
DOI: JANT Vol.6(No.2) 138-150, 2002
This paper addresses the problem of combining adaptive polarization processing and space-time processing for further performance improvement of radar target detection in clutter and jammer environments. Since the most straightforward cascade combinations have quite limited performance improvement potentials. we focus on the development of adaptive processing in the joing polarization-space-time domain. Unlike a direct extension of some existing space-time processing algorithms to the joint domain, the processing algorithm developed in this paper does not need a potentially costly polarization filter bank to cover the unknown target polarization parameter. The performance of the new algorithm is derived and evaluated in terms of the probability of detection and the probability of false alarm, and it is compared with other algorithms that do not utilize the polarization information or assume that the target polarization is known.
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Effect of Impulsive Noise in Bluetooth Multi-Piconet using ARQ Scheme
김도균 Do Gyun Kim , 노재성 Jae Sung Roh , 조성준 Sung Joon Cho , 김정선 Jung Sun Kim
6(2) 151-157, 2002
김도균 Do Gyun Kim , 노재성 Jae Sung Roh , 조성준 Sung Joon Cho , 김정선 Jung Sun Kim
DOI: JANT Vol.6(No.2) 151-157, 2002
This paper has investigated the PER performance and the packet throughput of Bluetooth multipiconet in the presence of impulsive noise. Rician fading, and co-channel interference. Specially, it is simulated the effect of co-channel interference in Bluetooth multi-piconet. From the simulation results, it is obtained that the co-channel interference due to multi-piconet and impulsive noise affects performance of Bluetooth multi-piconet. And, we have known that the SAQ-ARQ method is very efficient to improve the performance of Bluetooth packet transmission
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Performance Analysis of WAP Packet Considering Multi-Slot SAR-QT Algorithm in Bluetooth Ad hoc Network
문일영 Il Young Moon , 노재성 Jae Sung Roh , 조성준 Sung Joon Cho
6(2) 158-167, 2002
문일영 Il Young Moon , 노재성 Jae Sung Roh , 조성준 Sung Joon Cho
DOI: JANT Vol.6(No.2) 158-167, 2002
In this paper, it is analyzed that WAP pachket transmission time to improve performance of WAP using SAR-QT algorithm in Bluetooth channel. The order for SAR-QT algorithm to improve the transfer capability, it is fragmented in WTP total messages that are coming down from upper layer and then the packets are sent one at time in baseband. And it is studied that transmission time for WAP over Bluetooth according to DMI, DM3 or DM5 packet type using SAR-QT algorithm in Bluetooth piconet environment. This SAR-QT algorithm decreases WAP packet transmission time of L2CAP baseband packets by sending packet that are spanning multiple slots. From the results, in WAP over Bluetooth channels, it is found out that WTP packet size ougth to be increased to decrease transmission time of WAP packet. In addition, considering BER in wireless channel. optimal WTP packet size is achieved for WAP over Bluetooth in a Rician fading environment.
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학회자료
6(2) 168-168, 2002
학회자료
DOI: JANT Vol.6(No.2) 168-168, 2002
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