Go to the main menu
Skip to content
Go to bottom
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 8, Issue 2 - Dec 2004
Volume 8, Issue 1 - Jun 2004
Selecting the target year
Transmission of Image Embedded with Robust Watermark through OFDM/16QAM System
Won, Gi-Sup ; Roh, Jae-Sung ; Cho, Sung-Joon ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 1~9
In this paper, we have studied the reliable scheme for transmission of digital watermarking-inserted image data through wireless channel. Multimedia data and watermarking data are degraded because of the high BER (Bit Error Rate) and the effect of fading in wireless channel. We adapt the error correction scheme for mitigating the degradation in watermarking data. We have evaluated the error performance of watermarking data modulated by OFDM/16QAM and sent through Rician fading channel. The simulation results show that when error correcting scheme is used the watermarking data can be detected without severe error even though watermarking-inserted image data is suffered from severe damage.
Performance Analysis of Quasi-Orthogonal Space-Time Block Coded OFDM Systems
Hwang, Kyu-Sang ; Yi, Jong-Sik ; Jong, Jae-Pil ; Oh, Chang-Heon ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 10~18
As a technique for high-quality multimedia service in down-link, the transmit diversity schemes using a orthogonal space-time block codes were proposed. But if the number of transmit antenna is three or more, it was impossible to obtain full diversity gain because of the decline of spectral efficiency. Accordingly, the quasi-orthogonal space-time block code that not required a additional bandwidth was proposed. But using a space-time block codes, the transmit diversity schemes were verified over quasi-static and frequency non-selective channels. Therefore, in this paper, we analyze the performance of OFDM systems, which a frequency selective channel equalized a frequency non-selective channel, adapting the quasi-orthogonal space-time block code, and compare they to the conventional orthogonal space-time block coded OFDM systems.
Development of Low-Cost Automatic Flight Control System for an Unmanned Target Drone
Lee, Jang-Ho ; Ryu, Hyeok ; Kim, Jae-Eun ; Ahn, Iee-Ki ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 19~26
This paper deals with the automatic flight control system for an unmanned target drone which is operated by an army as an anti-air gun shooting training. By automation of unmanned target drone that is manually operated by external pilot, pilot can reduce workload and an army can reduce the budget. Most UAVs which are developed until today use high-cost sensors as AHRS and IMU to measure the attitude, but those are contradictory for the reduction of budget. This paper says the development of low-cost automatic flight control system which makes possible of automatic flight with low-cost sensors. We have developed the integrated automatic flight control system by integrating electricity module, switching module, monitoring module and RC receiver as an one module. We also prove the performance of automatic flight control system by flight test.
Design of Kinematic Position-Domain DGNSS Filters
Lee, Hyung Keun ; Jee, Gyu-In ; Rizos, Chris ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 26~37
Consistent and realistic error covariance information is important for position estimation, error analysis, fault detection, and integer ambiguity resolution for differential GNSS. In designing a position domain carrier-smoothed-code filter where incremental carrier phases are used for time-propagation, formulation of consistent error covariance information is not easy due to being bounded and temporal correlation of propagation noises. To provide consistent and correct error covariance information, this paper proposes two recursive filter algorithms based on carrier-smoothed-code techniques: (a) the stepwise optimal position projection filter and (b) the stepwise unbiased position projection filter. A Monte-Carlo simulation result shows that the proposed filter algorithms actually generate consistent error covariance information and the neglection of carrier phase noise induces optimistic error covariance information. It is also shown that the stepwise unbiased position projection filter is attractive since its performance is good and its computational burden is moderate.
Design and Noise Figure Analysis of Coherent Transceiver for Airborne Radar
Woo, Duk-Jae ; Kim, Sang-Joong ; Lee, Taek-Kyung ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 38~47
To achieve functions of doppler measurement, MTI(Moving Target Indicator), high-resolution, and others in radar system, all circuits of transmitter and receiver are to be performed in coherent system. In this paper, we use TWTA(Traveling Wave Tube Amplifier), STALO(Stable Local Oscillator) and COHO(Coherent Oscillator) to design of coherent radar transceiver, and calculates noise figure of designed receiver. Using radar equation calculated noise figure, maximum detecting range of each transmitting mode can be calculated.
A Study On the Tracking Antenna System for a Moving Vehicle by the Embedded Linux
Kim, Jong-Kwon ; Woo, Gui-Aee ; Cho, Kyeum-Rae ; Lee, Dae-Woo ; Jang, Chul-Soon ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 49~57
In This paper the embedded linux based embedded control system was used and the tracking antenna system was studied for data link and communication between moving vehicles. A microprocessor based embedded controller is equipped with SA-1110 board and this embedded controller can control the azimuth and the elevation angle of the antenna. The relative position and attitude for pointing are calculated by using the GPS position signals from the moving vehicle. To verify the performance of the designed embedded antenna system, the orbit information of the Arirang satellite(from KARI) is used.
A Study on the Design of VCO Using Junction Capacitance of Active Element
Kang, Suk-Youb ; Park, Wook-Ki ; Go, Min-Ho ; Park, Hyo-Dal ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 57~65
In this paper, keeping pace with light weight, pocket-size, lower-price, we design VCO(Voltage Controlled Oscillator) X/Ku band for using at public RD(Radar Detector) to apply to controlled voltage on base in transistor which used as a oscillator, without using varactor diode in part of VCO tuner. As a result of simulation, we conclude VCO could be have 110 MHz by controlled voltage 4.25 V to 4.80 V and show its output 9.63 dBm at operating frequency, 11.46 GHz, and its phase noise -107.2 dBc at 1 MHz offset frequency. So it turned out suitable performance for commercial use.
Performance Enhancement of CSMA/CA MAC DCF Protocol for IEEE 802.11a Wireless LANs
Moon, Il-Young ; Roh, Jae-Sung ; Cho, Sung-Joon ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 65~72
A basic access method using for IEEE 802.11a wireless LANs is the DCF method that is based on the CSMA/CA. But, Since IEEE 802.11 MAC layer uses original backoff algorithm (Exponential backoff method), when collision occurs, the size of contention windows increases the double size. Hence, packet transmission delay time increases and efficiency is decreased by original backoff scheme. In this paper, we have analyzed TCP packet transmission time of IEEE 802.11 MAC DCF protocol for wireless LANs using a proposed enhanced backoff algorithm. From the results, in OFDM/quadrature phase shift keying channel (QPSK), we can achieve that the transmission time in wireless channel decreases as the TCP packet size increases and based on the data collected, we can infer the correlation between TCP packet size and total message transmission time, allowing for an inference of the optimal packet size in the TCP layer.
Channel Modeling for UWB MB-OFDM System Considering RF Frequency Hopping
Noh, JungHo ; Heo, Joo ; Chang, KyungHi ;
The Journal of Advanced Navigation Technology, volume 8, issue 1, 2004, Pages 73~80
In the case of Non-Line-of-Sight (NLOS), common telecommunication systems typically have Rayleigh distributed amplitude characteristics. However measurement result of Ultra Wideband (UWB) Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) system which is proposed as one of candidate standard in IEEE 802. 15. 3a for Wireless Personal Area Network (WPAN) shows that it has independent log normal fading in each cluster as well as in each ray within the cluster. Based on this clustering phenomenon observed, MB-OFDM channel model derived from Saleh-Valenzuela model with a couple of slight modifications. In this paper, channel remodeling for RF frequency hopping in MB-OFDM system is achieved, and performances of MB-OFDM system for each channel mode and data rate are verified using modified channel model.