• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.657-662
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• 2008

Inter-radar interferences may cause the critical impact to the radar detection performance because radar operates with high power and wideband. In this paper, the international criteria for radar interference protection is reviewed based on the ITU-R recommendation, and the radar interference analysis model is presented by taking into account the radar operating environments such as ground, airborne and spaceborne radars. Finally, the simulation results are presented with the interference Impact analysis in various radar environments.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.90-97
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• 2013

Recently, intelligent transportation system based on image processing has been developed. In this paper, we propose a collision detection algorithm based on the analysis of motion vectors and the staying periods of vehicles in intersections. Objects in the region of interest are extracted from the subtraction image between background images based on Gaussian mixture model and input images. Collisions and traffic jams are detected by analysing measured motion vectors of vehicles and their staying periods in intersections. Experiments are performed on video sequences actually recoded at intersections. Correct detection rate and false alarm rate are 85.7% and 7.7%, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.2050-2058
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• 2011

The objective of this thesis is to research the software requirement management system for the development of operational flight program (OFP) which is embedded in aircraft avionics. It offers the function to record the requirement revision log. In fact, the COTS (commercial off-the-shelf) program which has similar function already exists in the market. But this kind of software programs are too complicated and relatively expensive in acquisition. Furthermore, they require too expensive maintenance cost, medium sized business company, this thesis intended to provide the software requirement management system that can be simply installed and easily used.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.6
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• pp.618-638
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• 2020

An unmanned aerial vehicle(UAV) refers to an aircraft that has all or part of its functions to autonomously fly by grasping the surrounding environment by remote control on the ground without a pilot on board. With the development of unmanned aerial technology, civil/military forces are developing unmanned aerial vehicles for various purposes. In order to control unmanned aerial vehicles from the ground, communication protocols between unmanned aerial vehicles and ground control equipment are required, and civil/military forces have developed and used a photocall for different purposes. In this study, the characteristics of the MAVLink protocol used in the private sector and the STANAG 4586 protocol used in the military are compared/analyzed in detail to find elements to complement each other and to draw improvement measures for protocol unification.

• Journal of Advanced Navigation Technology
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• v.6 no.3
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• pp.231-240
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• 2002

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.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.217-226
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• 2003

Recently Lim has proposed a linear, recursive, unbiased minimum variance filter for a maneuvering target based on the maneuver dynamics modeled as a jump process of Poisson-type. In the proposed filter it was assumed that the state transition parameters of the jump used for target maneuver modeling are a priori known to the filter. However, in most cases they are not known in practice. In this paper, we consider the influence of system (target) modeling error on the performance of the proposed tracking filter arising from the maneuver tracking. For qualitative analysis Monte-Carlo simulations are carried out against employing the maneuver model with different state transition parameters from the actual values.

• Journal of Advanced Navigation Technology
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• v.4 no.1
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• pp.67-77
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• 2000

This paper proposes a reduction scheme for codebook search time in the adaptive codebook using wavelet transformed coefficients. In a CELP coder, pitch estimation with a combined open loop and closed loop search in adaptive codebook needs a lengthy search. More precisely, the pitch search using autocorrelation function over all possible ranges has been shown inefficient compared to the consuming time. In this paper, we propose a new adaptive codebook search algorithm which ensures the same position for the pitch with maximum wavelet coefficient over various scaling factors in Dyadic wavelet transform. A new adaptive codebook search algorithm reduces 25% conventional search time with almost the same quality of speech.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1138-1144
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• 2009

The velocity and acceleration of the ground moving target can cause the target position to be displaced and defocused in the SAR image. In this paper, the displacement compensation scheme is presented to correct the displaced position and defocused moving target image in the DPCA based SAR-GMTI system. The influence of the ground moving target due to the velocity and acceleration is analyzed in range and azimuth directions, and its compensation method is presented with the simulation results. The performance of the proposed method is compared with respect to the estimated velocity and defocused quantity in both range and azimuth directions.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.610-617
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• 2010

This paper analyzes the characteristics of abnormal broadcast GPS ephemeris by comparing distances between the receiver and the satellites. Effects of abnormal ephemeris on receiver's position estimate are closely related with range errors caused by variations of satellite positions. In more detail each range error depends on the satellite position error and the line of sight vector. Based on the fact, the ephemeris parameters are classified into three types depending on the size, the shape, and the shape of the satellite orbit to analyze the fault characteristics. The effects of satellite position errors caused by the three type s of parameters on the receiver's position estimate are analyze d in detail.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.559-566
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• 2008

In this paper, we propose a voice instruction-based takeoff system for aircraft including unmanned aerial vehicle (UAV). The system consists of voice recognition (VR), flight state checking and instruction (command) execution. Employing VR technology, the proposed takeoff system can provide simplified and more reliable takeoff procedures to pilots. By virtue of the VR-based system it is expected that human errors during takeoff phase can be reduced and further navigation safety can be improved.