• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.99-107
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• 2014

Abruptly occurred obstacles on highway threaten driving safety. Radar draws the attention to the collision avoidance system because it can be fully operational in all weather, and day and night condition. This paper presents the design, implementation and performance test results of pulsed Doppler radar system for detection and warning of road obstacles. The system is designed to consider highway environment and detection capability about various fixed and moving obstacles. The system consists of 4 subsystems, which include antenna unit, transmitter and receiver unit, radar signal & data processing unit, and controller & display unit. The core technologies include clutter map based change detection for fixed obstacles detection, Doppler estimation for velocity detection of moving targets, and azimuth angle estimation method using monopulse for lane estimation and tracking. The design performance of the developed radar system is verified through experiments using a fixed reference target and moving vehicles in test highway.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.98-104
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• 2004

When a straight-in landing from an instrument approach using ILS or VOR/DME is not possible or desirable because of topographical reason or bad weather, a circling approach maneuver is initiated by the pilot to align the aircraft with a runway for landing. Visual contact with the runway is necessary while conducting a circle to land maneuver. This research is to develop a new warning system based on a convention marker system which alerts pilots to watch out for exceeding the circling approach area. The airborne system also uses the same receiver unit without any new installations. The objective of this research is to design and develop a Yagi antenna in a special form. The research includes computer simulations to determine the size of antenna radiation pattern and to compute an expected flight path in case of alarm to validate effectiveness of the system.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.315-321
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• 2023

In this paper, we propose an algorithm that jointly estimates the location and velocity of a near-field moving target in a pulse radar system. The proposed algorithm estimates the location and velocity corresponding to the outcome of orthogonal matching pursuit (OMP) in a 4-dimensional (4D) location-velocity space. To address the high computational complexity of 4D parameter joint estimation, we propose an algorithm that iteratively estimates the target's 2D location and velocity sequentially. Through simulations, we analyze the estimation performance and verify the computational efficiency of the proposed algorithm.

• Journal of Advanced Navigation Technology
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• v.22 no.3
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• pp.179-188
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• 2018

In developing avionics systems, safety analysis and evaluation specified in SAE ARP4761 (Methods and Guidelines for Civil Aviation System and Equipment Safety Assessment Process) are carried out to prevent air accidents. Safety analysis requires knowledge of the abnormal state of the system, not its normal state, and its interrelationships with other standards. Therefore, a tool that automatically outputs data which proves compliance with safety certification standards is required. In this study,In this study, Schematized the safety analysis procedure of the specification and studied the method of applying the safety analysis CAD tools to individual procedure. As an example study, ARP4761 analysis was performed on the wheel brake system (WBS) of the ARP4761 appendix.

• Journal of Advanced Navigation Technology
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• v.5 no.2
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• pp.134-140
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• 2001

Ultra Wideband(UWB) system uses wide band signal, which power spectral density likes as a noise floor, so UWB system can be used high speed communication without interfering with other communication system. As this system doesn't use carrier, its structure would be very simple and consume very low power. But conventional UWB system uses Pulse Positioning Modulation(PPM) Method. Therefore it could be to produce discrete power spectrum which decreases system efficiency unintentionally. For eliminating discrete power spectrum and further Euclidean distance, we propose UWB system using Antipodal signal. And we design and simulate antipodal tranceiver using Advanced Design System(ADS).

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.325-331
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• 2017

As a GPS stability problem arises, MLAT system is spotlighted as an alternative technology of ADS-B. MLAT system has a high position accuracy as much as ADS-B. Also, MLAT receives the mode A,C,S, and 1090ES(ADS-B) signals from the mounted aircraft transponder. MLAT receives signals from several receiver units and calculates aircraft positions. MLAT has ADS-B level positioning accurarcy using GPS and can calculate the position information with objects independently. According to global environment changes, Local area multiltilateration(LAM) surveillance system is under development for moving vehicles and aircraft detection in airport. These are still under testing in Tae-an Airfield. In the paper, we analyzed the performance by comparing the calculated position data from MLAT to RTK. In order to confirm the position accuracy of MLAT and the deviation of position data between fixed target and moving target on the ground during the field test in Tae-an Airfield.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.3
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• pp.365-371
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• 2014

It is essential for the combined military weapon system to be equipped with interoperability for the efficient combat operation in the modern warfare environment. Since most of modern military systems utilize the electromagnetic wave for the radio communication in the network-centric warfare system, they can be vulnerable to the mutual interference among the adjacent combined military systems. In this paper, the typical radio communication systems are modeled with the modulation types of both spread and non-spread spectrum system. The various interference signals were generated for the simulation of the mutual interference influence from the adjacent radar and communication systems. The simulation results show that the detection performance of the victim communication receiver is seriously affected by the various interferences such as the types of modulation and the ratio of the overlapping bandwidth of the adjacent interferers. This result will be useful for defining the criteria of the interference protection in the combined military system for the interoperability in the future.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1116-1124
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• 1995

Using a cycle simulation program developed by authors, some thermodynamic characteristics of an aircraft ECS under various operating conditions are studied. When the inlet temperature of cockpit and avionics bay, as well as ram air flow, is held fixed, the effect of the change of regulated bleed pressure is examined. When the regulated bleed pressure, and the cockpit and avionics bay inlet temperature are fixed, the effect of the change of ram air flow is also investigated.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.8
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• pp.32-38
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• 1998

In this paper, we design a robust controller for trajectory control of n-link robot manipulators with bounded parametric uncertainties. The proposed control scheme with integral control improves tracking error due to limit of the robust feedback gains and use of continuous control input for chattering rejection. The integral of the tracking error is augmented to the error system equation and the stability of the closed-loop system is achieved. The performance of the proposed method is demonstrated by simulation on a 2-link manipulator.