• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.598-606
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• 2011

The importance of avionics systems has increased to a significant level in modern aircraft development. Modern avionics system is a complex integrated system of state-of-art hardware and software technology. Specifying the avionics system architecture is the most important task throughout the avionics system design process. This paper reviews modern avionics system architectures and proposes an effective avionics architecture suitable for modern attack helicopters.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.70-77
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• 2019

This study presents the numerical investigation of the trajectory of rocket launched from a helicopter. The nonlinear mathematical model of armed configuration of UH-60 helicopter was developed while Hydra 70 unguided rocket was modeled to simulate the rocket behavior. The effects of various inflow models on the launched rocket trajectory are obtained. Similarly, rocket launch simulation was performed to determine the unsafe flight maneuver condition where the rocket trajectory is critically close to the helicopter main rotor tip path plane.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.3
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• pp.217-224
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• 2020

The use of a high gain flight control system to achieve high bandwidth performance increase the instability of a helicopter. To investigate these phenomena numerically, high fidelity EC155B1 helicopter model and simplified flight control system that include actuator, digital processor and noise rejection filter was developed. A study conducts an analytical investigation of roll axis stability of the helicopter model as feedback gain increases. And this study analyzes roll-rate and roll-attitude feedback gains limited by rotor flap mode. The results indicate that the phase delays caused by the filter can severely limit the usable values of the roll-rate and roll-attitude feedback gains.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.185-192
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• 2005

The aim of this paper is to analyze handling qualities of tiltrotor aircraft(TR-S4) in helicopter flight mode including hovering and forward flight. Analysis of handling qualities is composed of aircraft response to control inputs that effect on stability and controllability. In short term response analysis, bandwidth is the critical parameter for small amplitude motions since it relates to the ability of a pilot to crisply start and stop maneuver. The handling qualities of TR-S4 in helicopter mode are analyzed with a SAS and an attitude controller and are satisfied level 1 in almost criteria with simulation of TR-S4 6-DOF nonlinear model.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.436-447
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• 2014

The major elements of avionics system architecture are requirements, Real Time Operating System, message communication, memory, and data format etc. Herein describes a state-of-the-art development trend for the avionics system architecture, system requirements and data bus among the major elements of avionics system. While, domestic technology has been tried to Integrated Modular Avionics(IMA) system based on the Avionics Full Duplex Switched Ethernet(AFDX) technology during Light Attack Helicopter(LAH) project in Korea, but not yet proved as the product case in Full Scale Development Phase. The avionics system architecture considering the domestic inexperience of the IMA system architecture are suggested for the Next-generation Corps Unmanned Aircraft System.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.173-180
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• 2006

An airborne radar is an essential aviation electronic system of the aircraft to perform various missions in all weather environments. This paper presents the design, development, and test results of the multi-mode pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRU units, which include ANTU(Antenna Unit), TRU(Tx Rx Unit), RSDU(Radar Signal & Data Processing Unit) and DISU(Display Unit). The developed technologies include the TACCAR processor, planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, DSP based Doppler FFT filtering, adaptive CFAR, IMU, and tracking capability. The design performance of the developed radar system is verified through various helicopter-borne field tests including MTD (Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.798-803
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• 2013

In this paper, the activities of North America to enhance the flight safety of helicopter were introduced. In North America, by 2009, 49% of worldwide civil helicopters are in operation. The development trends of North America to enhance the flight safety of helicopter are expected to have a significant impact to the other helicopter operating areas. The analysis of the case of Gulf of Mexico where large fleet of Helicopter in operations, FAA's NextGen program, and the Canadian plan to comply with the ICAO's Aviation System Block Upgrades plan shows the direction of helicopter avionic development for enhancing the flight safety of helicopter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.258-261
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• 2012

Helicopter-borne FMCW radar altimeter obtains the altitude information using the beat frequency between the transmitted and reflected signal from the nadir direction. However, the altitude error may exist when the strong echoes are received from the large RCS at the off-nadir direction because of the wide beamwidth of the altimeter antenna. In this paper, in order to investigate the effect of the altitude error due to the large RCS around the off-nadir direction, the reflected signals were measured by using the corner reflectors displaced on the several reference ground positions, and the acquired signals were analyzed and compared in the spectral domain. The analysis results can be used for the improvement of the altitude accuracy in the radar altimeter.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.8
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• pp.759-769
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• 2013

Electronic equipment has been applied to virtually every area associated with commercial, industrial, and military applications. Specifically, electronics have been incorporated into avionics components installed in aircraft. This equipment is exposed to dynamic loads such as vibration, shock, and acceleration. Especially, avionics components installed in a helicopter are subjected to simultaneous sine and random base excitations. These are denoted as sine on random vibrations according to MIL-STD-810F, Method 514.5. In the past, isolators have been applied to avionics components to reduce vibration and shock. However, an isolator applied to an avionics component installed in a helicopter can amplify the vibration magnitude, and damage the chassis, circuit card assembly, and the isolator itself via resonance at low-frequency sinusoidal vibrations. The objective of this study is to investigate the dynamic characteristics of an avionics component installed in a helicopter and the structural dynamic modification of its tray plate without an isolator using both a finite element analysis and experiments. The structure is optimized by dynamic loads that are selected by comparing the vibration, shock, and acceleration loads using vibration and shock response spectra. A finite element model(FEM) was constructed using a simplified geometry and valid element types that reflect the dynamic characteristics. The FEM was verified by an experimental modal analysis. Design parameters were extracted and selected to modify the structural dynamics using topology optimization, and design of experiments(DOE). A prototype of a modified model was constructed and its feasibility was evaluated using an FEM and a performance test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.369-370
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• 2009