• Journal of Navigation and Port Research
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• v.33 no.5
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• pp.303-308
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• 2009

Recently, unmanned systems have been studied and developed in various areas including aircrafts, automobiles and vessels. In addition, many researches about unmanned systems in Korea have been studying actively with the advancement of IT However, it is not satisfied with the result of the researches and developments. Bemuse of the reason we've here tried to make a very small USV which is a barge type. We applied the Great circle navigation calculation based on GPS to the autonomous navigation algorithm and used the LabVIEW 8.2 developed by NI corp. for programming The engine and rudder were controlled by pulse width modulation method. The engine system was composed of the DC motor and ESC(Electronic Speed Controller). It was also applied by the direct cooling system using DC motor pump. A very small USV was designed and made by ourself and it was verified the effectiveness of autonomous navigation algorithm through the tests at the sea.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.442-442
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• 2012

농업용저수지 수질측정 현황은 17,600여 개소 농업용저수지 중 농업용수 수질측정망 조사시설은 저수지 800개소이며, 농업용 호소로서 환경부 조사 시행 호소수질측정망시설 26개소(저수지 16개소, 담수호 10개소)를 포함한 826개소를 대상으로 농업용수 수질을 분석 평가하고 있다. 저수지 자율항법 자동수질측정을 위하여 개발한 운영시스템은 내용적측정 무인탐사선과의 연계운항 제어모듈 개발 및 저수지 수질측정을 위한 최적항로 운항모듈을 개발하였다. 자율항법 무인탐사선의 자동수질 측정을 위한 운항 제어 알고리즘 설계를 위하여 기존의 자율항법 탐사선의 운항 알고리즘과 수질자동 측정장치 제어 알고리즘을 분석하여 연계 제어모듈을 설계하고 프로그래밍 하였다. 운영과정은 선박운영 프로그램에서 수질모니터링 프로그램으로 Operation Start 명령을 전송하면 수질모니터링 프로그램에서 이 명령을 수신한 이후에 윈치제어 및 수질측정, 각 해당 수심에서 시료채수를 수행한 이후에 Opeartion End 신호를 선박운영 프로그램에 전송하면 다음 지점으로 이동할 수 있도록 하였다. 이를 통하여 효율적인 농업용저수지의 무인자동 수질측정 및 채수기술을 개발 제공하도록 하겠다.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.379-385
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• 2024

INS(inertial navigation system) aligns itself using gravity and Earth's rotational rate from accelerometers and gyro sensors when stationary. Typically, ZUPT(zero velocity update), which is based on a linear error model Kalman filter, is used when it is stationary. However, such algorithms assume stationary conditions, leading to increased alignment errors or filter divergence during maritime mooring due to wave-induced motion. This paper designs a mooring alignment algorithm for maritime platforms using a Kalman filter, which uses large heading angle error model and an initial position correction technique. And it is validated by simulation. Furthermore, it is confirmed that applying this to a rotational INS dramatically improves performance through the principle of bias cancellation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.6
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• pp.463-472
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• 2017

Inertial Navigation System Alignment is the process to determine direction cosine matrix which is the transformation matrix between the INS body frame and navigation frame. INS initial position value is necessary to INS attitude calculation, so that user should wait until he get such value to start the INS alignment. To remove the waiting time, we propose an alignment algorithm that immediately starts after the INS power on by using pseudo initial position input and then is completed with attitude error compensation by entering true position later. We analyse effect of INS sensor error on attitude in process of time and verify the performance and usefulness of the close-loop alignment algorithm which corrects attitude error from the change of initial position.

• Journal of Satellite, Information and Communications
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• v.2 no.1
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• pp.41-47
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• 2007

Software GNSS digitized IF signal simulator is being developed by ETRI as a part of development of software-based GNSS Test & evaluation Facility which will provide test and evaluation environment for various software level application and navigation algorithm in GNSS. Software GNSS IF signal simulator will provide digitized GNSS signal including GPS and Galileo. The requirement analysis and conceptual design for the Software GNSS IF signal simulator is presented in this paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.783-789
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• 2020

This paper proposes a new method for vision-based navigation using semantically segmented aerial images. Vision-based navigation can reinforce the vulnerability of the GPS/INS integrated navigation system. However, due to the visual and temporal difference between the aerial image and the database image, the existing image matching algorithms have difficulties being applied to aerial navigation problems. For this reason, this paper proposes a suitable matching method for the flight composed of navigational feature extraction through semantic segmentation followed by template matching. The proposed method shows excellent performance in simulation and even flight situations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.6
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• pp.502-511
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• 2016

Recently, many kind of smart projectiles are being developed. In case of smart projectile, studying in advance, it uses a navigation data acquired from the GNSS receiver to check its location on the geocentric(WGS84) coordinates and to estimate P.O.I(point of impact). However, because of various error inducing factors, the result of positioning involve some errors. We introduce the advanced algorithm for the reconstruction of a navigation trajectory using weighted PDOP, based on a simulated trajectory acquired from PRODAS. It is very fast and robust to noise and shows reliable output. It can be widely used to estimate an actual trajectory of a projectile.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.408-414
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• 2009

A GPS/INS system is widely used in the UGV to estimate position during the mission. However, there are few restrictions when a GPS/INS system used alone. For example, GPS provides precise location information but easily interrupted by external factors like weather, environment, etc. INS provides continuous location data but positioning errors grew very rapidly with time. Therefore, it is necessary to integrating multi-sensors for more continuous and correct position estimation. In this paper, we propose location estimation algorithm of the UGV for GPS/INS integrated system that combines Fuzzy Inference and Unscented Particle Filter(UPF) to improve navigation. Fuzzy inference provides the simplest method integrating GPS/INS and UPF is non-linear estimation filter well suited to the correction of errors. The performance of the proposed algorithm was tested to compare with other algorithms. the results show that the proposed algorithm is more accuracy in position estimation and ensures continuous position tracking.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.196-197
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• 2011

신뢰성 있는 위성합법기반의 위치정보 서비스 제공을 위해서는 오차정보서비스와 항법신호의 이상을 감시하는 서비스가 요구된다. 항법신호 이상감시는 그동안 단일 기준국에 대한 연구 위주로 진행되어 왔다. 본 연구에서는 단일 기준국이 아닌 다중 기준국을 기반으로 한 항법신호 이상을 감시하기 위한 소프트웨어를 설계하고 구현하는데 그 목적이 있다. 다중 기준국을 기반으로 한 항법신호 이상감시 소프트웨어는 GPS 메시지를 효과적으로 수집하는 수집부와, 수집된 데이터를 이용하여 다중 기준국에서의 항법신호를 감시하기 위한 알고리즘 처리부로 나누어 소프트웨어의 효과적인 동작을 위해 모듈화를 진행하였으며, 시스템에 대한 안정성 및 확장성을 고려하여 설계하였다. 본 연구를 통하여 단일 기준국에서는 확인할 수 없는 항법신호 이상을 정밀하게 탐지할 수 있게 되었으며, 오차정보 서비스를 제공하는데 있어 기반자료로 활용될 수 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.393-398
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• 2008

This paper suggests a GPS/INS navigation computer architecture that can be applied to small satellites. In order to implement a GPS/INS navigation system on a small satellite, the extreme environment in space such as radiation, micro-gravity, vacuum, etc. must be considered. In addition, a real-time processing ability is required for the GPS/INS navigation system since the formation flying of multiple small satellites is the ultimate goal. The developed navigation electronics utilizes a PowerPC-type MPC860T that has space environment heritage, and a pair of Atmega128s that has been implemented in KAUSAT-2 and has completed the space environment verification tests. The navigation algorithm is designed to work in VxWorks environment, ported in MPC860T.