• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1095-1109
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• 2021

The technology used to recognize the location and surroundings of autonomous vehicles is called SLAM. SLAM standsfor Simultaneously Localization and Mapping and hasrecently been actively utilized in research on autonomous vehicles,starting with robotic research. Expensive GPS, INS, LiDAR, RADAR, and Wheel Odometry allow precise magnetic positioning and mapping in centimeters. However, if it can secure similar accuracy as using cheaper Cameras and GPS data, it will contribute to advancing the era of autonomous driving. In this paper, we present a method for converging monocular camera with RTK-enabled GPS data to perform RMSE 33.7 cm localization and mapping on the urban road.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.171-182
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• 2019

Bicycles are a pollution-free means of transportation. In addition to leisure, the use of bicycles is increasing as alternative eco-friendly transportation. Accordingly, bicycle accidents are also increasing. The purpose of this study is to implement bicycle black box technology to identify situation when a bicycle accident occurs. Currently, bicycle black box products are mainly based on video cameras, and are commercially available by adding various functions mainly on high resolution cameras and are sold at high prices. If a bicycle accident occurs, quantitative data on the accident location at the time of the accident and the state of the bicycle at the time of the accident is required. In this study, IMU sensor used to obtain acceleration and slope, and time and coordinates are obtained. In addition, real-time acceleration and tilt data while is stored in memory card and by using Bluetooth transmit to the smart phone owned by the in real time to prevent accidents and to monitor status.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.2
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• pp.58-66
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• 2007

지상, 항공 및 우주를 이동하는 모든 물체는 반드시 자신의 자세를 결정하기 위해서 여러 가지 센서들을 장착하여 그 신호를 이용해서 자동 항법, 유도 및 제어를 수행한다. 이때, 동역학 특성이 빠른 시스템들은 반드시 각속도를 측정할 수 있어야 하는데 이를 해결하는 장비가 자이로인 것이다. 본 논문에서는 다양한 자이로를 소개하며 그 원리와 성능 그리고 적용 분야에 이르기까지 현황을 집중 분석하고 특히 세계적인 자이로 개발업체를 소개하면서 그 업체가 보유하고 있는 제품들을 일부 소개한다. 자이로는 초창기 김벌 시스템을 이용한 관성원리를 적용한 것부터 시작하여 현재는 광학 시스템을 적용한 RLG 및 FOG 자이로가 많은 분야에서 사용되고 있고, 최근 새롭게 부각되어 개발을 시작하고 있는 MEMS 자이로가 있는데 아직 우주 비행체 분야에서는 적용되지 못하고 있다. 그리고, 자이로의 큰 범주로 다루어지지는 않지만 자기력을 이용해서 회전체인 로터와 고정체인 플랫폼 사이에 기계식 접촉이 전혀 없는 새로운 시스템인 ESG 자이로도 일부 상용으로 생산되고 있다. 현재까지는 기계식 자이로의 정밀도 및 안정성이 광학식 자이로보다 우수하여 많이 사용되고 있지만 최근의 개발 추세로 보면 곧 광학식 자이로의 강세가 두드러질 것으로 보인다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.1
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• pp.73-78
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• 2007

The process and results of Captive Flight Test(CFT), conducted by Agency for Defense Development(ADD) using the Korean KTX-1 trainer and external fuel tank, are presented. Through over 150 sorties of CFT, the guided weapon system's critical subsystems like Seeker, Navigation Device and Technology, Inertial Sensor, and Radio Altimeter are tested and evaluated. Using the CFT, time and cost are saved in weapon system research and development procedure.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.10
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• pp.473-478
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• 2017

Drones require altitude holding in order to achieve flight objectives. The altitude holding of the drone is to repeat the operation of raising or lowering the drone according to the altitude information being measured in real-time. When the drones are maintained altitude, the drone's altitude will continue to change due to external factors such as imbalance in thrust due to difference in motor speed or wind. Therefore, in order to maintain the altitude of drone, we have to exactly measure the continuously changing altitude of the drone. Generally, the acceleration sensor is used for measuring the height of the drones. In this method, there is a problem that the measured value due to the integration error accumulates, and the drone's vibration is recognized by the altitude change. To solve the difficulty of the altitude measurement, commercial drones and existing studies are used for altitude measurement together with acceleration sensors by adding other sensors. However, most of the additional sensors have a limitation on the measurement distance and when the sensors are used together, the calculation processing of the sensor values increases and the altitude measurement speed is delayed. Therefore, it is necessary to accurately measure the altitude of the drone without considering additional sensors or devices. In this paper, we propose a measurement algorithm that improves general altitude measurement method using acceleration sensor and show that accuracy of altitude holding and altitude measurement is improved as a result of applying this algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.327-334
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• 2013

In August 2012 the first CanSat competition was hosted by the Satellite Research Center of KAIST under auspice of the Ministry of Education, Science and Technology. The present authors team won the first prize in the university session. In this paper the overall procedure of the CanSat project presented from the conceptual design stage to the final launch test. As the compulsory mission CanSat should send GPS data and attitude information to the ground station which in practice was performed via Bluetooth channel. In addition our CanSat is designed to trace the sun for the solar panels supplying electric power of satellite. IMU and servo motors are used for the attitude control in order that the solar sensor of the CanSat is always direct towards the sun. Launching of CanSat was simulated by dropping from a balloon at the height of around 150m via parachute. Launching test results showed that the attitude control of the CanSat and its solar sensing function were successful.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.139-147
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• 1999

In this paper, we present the new angular velocity pick-off method for DTG (dynamically tuned gyroscope) which is widely used in various inertial navigation systems and motion control systems. In case of the external angular velocity input, the proposed scheme can make a smaller tilt-angle rather than that of conventional PI method in the transient and steady state because it has an additional inner rebalance loop with a mathematical model of the real gyroscope. So, without any mechanical redesign of the DTG, its dynamic range can be enlarged by the proposed method. The theoretical analysis and simulation model of DTG with the proposed scheme are given. Finally, the proposed scheme is verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.302-313
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• 2018

As the demand for indoor location recognition system has been rapidly increased in accordance with the increasing use of smart devices and the increasing use of augmented reality, indoor positioning systems(IPS) using BLE (Bluetooth Lower Energy) beacons and UWB (Ultra Wide Band) have been developed. In this paper, a positioning plate is generated by using trilateration technique based on BLE Beacon and using RSSI (Received Signal Strength Indicator). The resultant value is used to calculate the PDR-based coordinates using the positioning element of the Inertial Measurement Unit sensor, We propose a precise indoor positioning algorithm that combines RSSI and PDR technique. Based on the plate algorithm proposed in this paper, the experiment have done at large scale indoor sports arena and airport, and the results were successfully verified by 65% accuracy improvement with average 2.2m error.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1167-1175
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• 2010

This paper presents the use of the inertial measurement unit information and the infrared sector information for getting the position of an object. Travel distance is usually calculated from the double integration of the accelerometer output with respect to time; however, the accumulated errors due to the drift are inevitable. The orientation change of the accelerometer also causes error because the gravity is added to the measured acceleration. Unless three axis orientations are completely identified, the accelerometer alone does not provide correct acceleration for estimating the travel distance. We propose a way of minimizing the error due to the change of the orientation. In order to reduce the accumulated error, the infrared sector information is fused with the inertial measurement unit information. Infrared sector information has highly deterministic characteristics, different from RFID. By putting several infrared emitters on the ceiling, the floor is divided into many different sectors and each sector is set to have a unique identification. Infrared light based sector information tells the sector the object is in, but the size of the uncertainty is too large if only the sector information is used. This paper presents an algorithm which combines both the inertial measurement unit information and the sector information so that the size of the uncertainty becomes smaller. It also introduces a framework which can be used with other types of the artificial landmarks. The characteristics of the developed infrared light based sector and the proposed algorithm are verified from the experiments.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.60-67
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• 2022

An Electro-Optical Tracking System (EOTS) is an electric optical system with EO/IR cameras, laser sensors, and an IMU. The EOTS calculates coordinates of targets, using attitude and acceleration measured by the IMU. In particular for an armed aircraft, the performance of the weapon system depends on how quickly and accurately it acquires the target coordinates. The IMU should be operated after alignment is complete, to meet the coordinate accuracy required by the weapon system so the initial stabilization time of the IMU should be reduced, by quickly measuring the attitude and acceleration. Alignment is the process of determining the initial attitude by resolving the attitude error of the IMU, and the IMU of mission equipment such as an airborne EOTS, uses velocity matching based on the velocity from GPS/INS for aircraft navigation. In this paper, a method is presented to improve the transfer alignment performance of the airborne EOTS, by maneuvering aircraft and the mission equipment. First, the performance factor of the alignment was identified, as a heading error through the velocity matching model and simulation results. Then acceleration maneuvers and attitude changes were necessary, to correct the error. As a result of flight tests applied to an EOTS on a OOO aircraft system, the transfer alignment performance was improved as the duration time was decreased, by more than five times when the aircraft accelerated by more than 0.2g and the EOTS was moving until 6.7deg/s.