• 로봇학회논문지
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• 제5권1호
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• pp.55-63
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• 2010

This paper describes performance improvement of GPS/DR Integration system using area decision algorithm and vehicle movement information. In GPS signal blockage area, i.e., tunnel and underground parking area, DR sensor errors are accumulated and navigation solution is gradually diverged. We use the car movement information according to moving area to correct the DR sensor error. Also, vehicle movement is decided as stop, straight line, turn and movement changing region through DR sensor data analysis. The car experiment is performed to verify the supposed method. The results show that supposed method provides small position and heading error than previous method.

• 한국군사과학기술학회지
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• 제14권1호
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• pp.49-54
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• 2011

This paper addresses the performance comparisons of the GPS pseudorange and pseudorange rate measurements in the tightly coupled INS/GPS Navigation systems. Even though the two measurements have the same ability in estimating level attitude errors, pseudorange rate has an advantage in improving estimating heading attitude error performance. The performance of pseudorange and pseudorange rate measurements is compared in numerical simulations and van test.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.91-91
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• 2000

In this paper, the error compensation method of the attitude reference system with low-cost IMU is proposed. In general, the attitude error calculated by gyro grows with time. Therefore the additional information is required to compensate the drift. The attitude angles can be bound by accelerometer mixing algorithm and the heading angle can be aided by GPS velocity information. The Kalman filter is used for error compensation. The result is verified by comparing with the attitude calculated by medium-grade IMU, LP-81.

• 한국농림기상학회지
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• 제19권4호
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• pp.246-251
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• 2017

벼의 생육에 있어서 중요한 역할을 하는 출수기를 예측하기 위해 작물모델이 사용될 수 있다. 벼의 생육을 모의하는 모델 중 널리 사용되던 ORYZA2000 모델이 개선되어 ORYZA (v3)가 최근에 보고되었다. 그러나, 최근까지 ORYZA (v3)의 국내 적용 가능성에 대해서는 연구가 이루어지지 않았다. 본 연구에서는 ORYZA (v3)를 이용하여 예측된 출수기의 신뢰성을 검토하였다. 또한, 새로운 모델에 요구되는 입력자료를 생성하는데 있어서의 편의성을 평가하였다. 국립농업과학원의 실험포장에서 2015년과 2016년에 걸쳐 중만생종인 신동진벼를 이용하여 화학비료 표준시비 조건에서 실험을 수행하였다. 입력자료는 실험에 사용한 재배관리자료, 기상청으로부터 수집한 기상자료, 흙토람으로부터 수집한 토양자료 및 Lee et al.(2015)에서 사용한 품종모수 자료를 사용하였다. 또한, 벼우량계통 지역적응시험에서 얻어진 출수기 관측자료와 예측자료를 비교하였다. 예측된 출수기는 인근 기상관측소에서 얻어진 기상입력 자료가 사용되었을 경우, 실제 출수기와 비교적 유사한 결과를 보였다. 예를 들어, 전주, 대구, 영남, 논산, 계화에서 예측된 출수기는 1일 이내의 상당히 작은 오차는 가졌다. 그러나, 기상자료가 비교적 멀리 떨어져 있거나 해안가 인근지역에 위치하여 출수기 관측지의 국지적 기상조건을 충분히 반영하지 못할 경우 상당한 오차가 발생하였다. ORYZA (v3)의 입력자료 생성과 관련한 편의성 측면에서는 기존의 자료 처리도구를 활용할 수 있는 기상 자료 확보는 비교적 용이할 것으로 판단되나, 토양자료에 대해서는 ORYZA 2000 모델의 입력자료에 추가적인 자료가 요구되어 토양자료 처리도구의 개발이 필요할 것으로 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.584-589
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• 1992

The 3-dimensional PPNG(Pure proportional navigation guidance) law was proposed about forty years ago, but the satisfactory analysis of its performance has not been presented since then. In this note, we prove under some reasonable assumptions that the missile guided according to this 3-dimensional PPNG law can always intercept a randomly maneuvering target if (1) the target acceleration varies with a certain bound, (2) the navigation constant is selected large and (3) the initial heading error is small. We introduce a Lyapunov-like method that proves to be a very powerful tool in obtaining our results.

• 제어로봇시스템학회논문지
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• 제19권8호
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• pp.661-666
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• 2013

A state feedback controller with integration of output error is proposed for way-point tracking of an AUV (Autonomous Underwater Vehicle). For the steering control on the XY plane, the proposed controller uses three state variables (sway velocity, yaw rate, heading angle) and the integral of the steering error, and for the depth control on the XZ plane, it uses four state variables (pitch rate, depth, pitch angle) and the integral of the depth error. From the simulation using Matlab/Simulink, we verify that the performance of the proposed controller is satisfactory within an error range of 1m from the target way-point for arbitrarily chosen sets of consecutive way-points.

• ETRI Journal
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• 제27권3호
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• pp.280-288
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• 2005

This paper presents an efficient algorithm for using the two-axis magnetic compass in portable devices. The general magnetic compass module consists of a three-axis magnetic compass and a two-axis inclinometer to calculate tilt-compensated azimuth information. In this paper, the tilt error is compensated using just a two-axis magnetic compass and two-axis accelerometer. The third-axis data of the magnetic compass is estimated using coordinate information that includes the extended dip angle and tilt information. The extended dip angle is estimated during the normalization process. This algorithm can be used to provide the tilt-compensated heading information to small portable devices such as navigation systems, PDAs, cell phones, and so on.

• Journal of electromagnetic engineering and science
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• 제17권3호
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• pp.120-125
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• 2017

A satellite communication (Satcom) antenna mounted on a moving platform provides a controlled heading that enables a geosynchronous satellite to communicate with the ground. A monopulse tracking method is effective for antenna control on a vehicle when it vibrates severely. However, this method has unexpected obstacles and its control performance is insufficient. To improve its control performance, the control command and monopulse error, the signal delay, and the radome effect are evaluated through tests. The authors then propose a method to transform the antenna error from 3D coordinates to 2D antenna coordinates. As a result, the antenna control performance is improved. As indicated in this study, examining antenna systems using the monopulse method on moving platforms is possible by understanding the antenna test process.

• 제어로봇시스템학회논문지
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• 제18권11호
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• pp.1034-1039
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• 2012

In this paper, a structure of precise positioning based on satellite navigation system is proposed. The proposed system is consisted with three parts, range domain filter, navigation filter and position domain filter. The range domain filter generates carrier phase-smoothed-Doppler and Doppler-smoothed-code measurements. And the navigation filter calculates position and velocity using double-differenced code/carrier phase/Doppler measurements. Finally, position domain filter smooth position error, and it means enhancement of positioning performance. The proposed positioning method is evaluated by trajectory analysis using precise map date. As a result, the position error occurred by multipath or cycle slip was reduced and the calculated trajectory was in true lane.

• International Journal of Ocean System Engineering
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• 제1권2호
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• pp.102-109
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• 2011

This paper describes the implementation of a precise underwater navigation solution using a multiple sensor fusion technique based on USBL, GPS, DVL and AHRS measurements for the operation of a remotely operated mine disposal vehicle (MDV). The estimation of accurate 6DOF positions and attitudes is the key factor in executing dangerous and complicated missions. To implement the precise underwater navigation, two strategies are chosen in this paper. Firstly, the sensor frame alignment to the body frame is conducted to enhance the performance of a standalone dead-reckoning algorithm. Secondly, absolute position data measured by USBL is fused to prevent cumulative integration error. The heading alignment error is identified by comparing the measured absolute positions with the DR algorithm results. The performance of the developed approach is evaluated with the experimental data acquired by MDV in the South-sea trial.