• Current Research on Agriculture and Life Sciences
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• v.32 no.2
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• pp.79-84
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• 2014

The precision aerial application of agricultural unmanned helicopters has become a new paradigm for small farms with orchards, paddy, and upland fields. The needs of agricultural applications require easy and affordable control systems. Recent developments of MEMS technology based on inertial sensors and high speed DSP have enabled the fabrication of low-cost attitude system. Therefore, this study evaluates inertial MEMS sensors for estimating the attitude of an agricultural unmanned helicopter. The accuracies and errors of gyro and acceleration sensors were verified using a pendulum system. The true motion values were calculated using a theoretical estimation and absolute encoder measurement of the pendulum, and then the sensor output was compared with reference values. When comparing the sensor measurements and true values, the errors were determined to be 4.32~5.72%, 3.53~6.74%, and 3.91~4.16% for the gyro rate and x-, z- accelerations, respectively. Thus, the measurement results confirmed that the inertial sensors are effective for establishing an attitude and heading reference system (AHRES). The sensors would be constructed in gimbals for the estimating and proving attitude measurements in the following paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.41-48
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• 2019

This paper deals with a method of aligning an aircraft fuselage and an inertial navigation sensor using three-dimensional coordinates obtained by an optical method. In order to verify the feasibility, we introduce the method to accurately align the coordinate system of the inertial navigation sensor and the aircraft reference coordinate system. It is verified through simulation that reflects the error level of the measuring device. In addition, optimization method based alignment algorithm is proposed for connection between optical sensor and inertial navigation sensor.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.1
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• pp.18-24
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• 2015

Train positioning detection information is fundamental for high-speed railroad inspection, making it possible to simultaneously determine the status and evaluate the integrity of railroad equipment. This paper presents the results of measurements and an analysis of an inertial measurement unit (IMU) used as a positioning detection sensors. Acceleration and angular rate measurements from the IMU were analyzed in the amplitude and frequency domains, with a discussion on vibration and train motions. Using these results and GPS information, the positioning detection of a Korean tilting train express was performed from Naju station to Illo station on the Honam-line. The results of a synchronized analysis of sensor measurements and train motion can help in the design of a train location detection system and improve the positioning detection performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.11
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• pp.921-933
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• 2018

There is a method to enhance the pure navigation performance of INS(Inertial Navigation System) through the rotation of inertial measurement unit to compensate error sources of inertial sensors each other and that INS using this principle of operation is called rotational INS. In this paper, the exact error analysis of rotational INS based on ring laser gyro considering the coupling effect with gravity and earth rate is performed to evaluate the navigation performance by inertial sensor error sources. And error analysis and performance evaluation result confirmed by modelling and simulation is also proposed in this paper.

• Journal of the Korea Computer Graphics Society
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• v.19 no.4
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• pp.13-22
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• 2013

A motion capture system is widely used in movies, computer game, and computer animation industries because it allows for creating realistic human motions efficiently. The inertial motion capture system has several advantages over more popular vision-based systems in terms of the required space and cost. However, it suffers from low accuracy due to the relatively high noise levels of the inertial sensors. In particular, the accelerometer used for measuring gravity direction loses the accuracy when the sensor is moving with non-zero linear acceleration. In this paper, we propose a method to remove the linear acceleration component from the accelerometer data in order to improve the accuracy of measuring gravity direction. In addition, we develop a simple method to calibrate the joint axis of a link to which an inertial sensor belongs as well as the position of a sensor with respect to the link. The calibration enables attaching inertial sensors in an arbitrary position and orientation with respect to a link.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2392-2394
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• 2004

핸드헬드 3차원 동작 추적 장치는 새로운 Human Computer Interaction의 도구로 Wearable Computing, Ubiquitous Computing, 3차원 Game 등의 분야에 요구되어 지고 있다. 본 논문에서는 저가의 관성 센서를 사용한 소형의 핸드헬드 3차원 동작 추적 장치를 설계하였다. 특히, 저가의 관성 센서를 적용하는데 있어 센서신호처리의 문제점을 제시하고, 문제점을 제거하기 위한 신호 처리 방법과 관성센서의 누적오차를 줄이기 위한 방법을 제안하고 실험으로 입증하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.191-192
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• 2011

MEMS 기반 관성 센서를 이용한 항법장치를 개발하는 경우, 칼만 필터(Kalman Filter, KF) 구축 여부에 따라 그 성능이 결정된다. 특히 해상에서 이러한 MEMS 기반 관성항법 장치를 사용하는 경우에는, 육상과 달리 다양한 제약조건이 따르게 된다. KF는 선형과 비선형으로 구분되고, 비선형은 다시 확장 KF와 Unscented KF, Particle KF 등 다양한 것이 연구 개발되어 있는데, 해상에 적용하기 위해서는 이러한 다양한 필터들의 특징과 추가 요청사항 등을 사전 조사할 필요가 있다. 본 연구에서는 기존 개발된 KF를 조사하여 해상용 MEMS 기반 관성 항법장치를 개발하는 경우 필요한 필터 구성 방법을 조사하여 문제점을 살펴보고, 이 문제 해결을 위한 방안을 검토하였다.

• 전기의세계
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• v.61 no.12
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• pp.25-28
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• 2012

• The Magazine of the IEIE
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• v.28 no.10
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• pp.39-44
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• 2001

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.357-358
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• 2008

본 논문은 GPS를 이용한 무인 비행체의 자율비행에 관한 연구를 다루었다. 비행체의 종류는 크게 고정익기와 회전익기로 나뉘는데 본 연구에서는 회전익기의 형태를 가진 Quarter Vehicle을 사용하였다. Quarter Vehicle은 4개의 프로펠러에 의한 양력과 회전 반발력으로 비행을 한다. 이때의 양력은 수평면에 대해 수직으로 추력을 발생시키므로 다른 비행체보다 불안정하며 이를 안정하게 제어하기 위해 관성 센서를 적용하여 균형을 유지한다. 본 연구에서는 UAV의 자세와 균형을 안정적으로 유지하기 위해 관성센서를 적용하였으며 GPS를 활용하여 독립적인 자율비행이 가능하도록 하였다. 정확한 위치정보를 제공하는 GPS는 3개 이상의 위성으로부터 시간 및 위치 정보를 받아 좌표를 계산하고 비행체의 위치, 속도 및 방향을 결정하여 자율 비행이 가능하도록 한다. 또한 초형 지자기센서를 비행체에 적용하여 GPS의 방향 정보를 보완하도록 하였다. 본 논문에서는 무인 비행체의 자율비행의 기초가 되는 위치좌표 계산을 위한 GPS의 적용 방법과 비행경로계획 알고리즘을 제시 한다.