• Geophysics and Geophysical Exploration
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• v.23 no.4
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• pp.243-252
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• 2020

To share an understanding of trajectory measurement in surveys using borehole, this tutorial summarizes the relevant mathematical principles of the borehole deviation survey based on coordinate transform. For uncased or open holes, calculations of the azimuth-deviation-tool face rotation using three-component accelerometer and magnetometer measurements are summarized. For the steel-cased holes, calculations are based on the time-derivative formula of the coordinate transform matrix; yaw-pitch-roll angles through time are mathematically determined by integrating the threecomponent angular velocity measurements from the gyroscope while also removing the Earth's rotation effect. Sensor and data fusion to increase the accuracy of borehole deviation survey is explained with an example of the method. These principles of borehole deviation surveys can be adapted for attitude estimation in air-borne surveys or for positioning in tunnels where global positioning system (GPS) signals cannot be accessed. Information on the optimization filter that must be incorporated in sensor fusion is introduced to help future research.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.867-874
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• 2021

The IoT (Internet of Things) technology is rapidly becoming an important consideration in many engineering fields in the current 4th industrial era. In recent years, the concepts of digital shipbuilding and smart factories have been adopted as trends in shipyards. However, there is active interest in research on implementing autonomous driving in autonomous vehicles and airplanes, which is currently available in commercial form in a limited capacity. The present study is regarding the path-tracking performance of a boat to accomplish an autonomous driving mission using a flight controller (FC) and real-time kinematic (RTK) global positioning system (GPS) based on an open-source Ardupilot; an actual sea test is also performed using this system on a calm lake. The boat's mission is to evaluate the maneuverability of the self-driving process to a specific point and returning to the home position. For a given speed, the difference between the preset mission trajectory and actual operational trajectory was analyzed, and a series of studies were conducted on the applicability of the system to ships. In addition, the movements and maneuverability of the OmniX-type hull with four propellers were investigated, and the driving path-tracking performance was observed to increase by a maximum of 48%.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.95-104
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• 2015

Recently, collecting and analyzing method of users location has been studied due to the development of mobile devices. There is analyzing method using Semantic Location History in order to identify of characteristics and extract pattern and predict trajectory of users. We should extraction of Stay Point in order to use Semantic Location History. The Conventional extraction method of Stay Point is not accuracy of location of Stay Points because it does not specify the GPS log of users. Also, Conventional extraction method of Stay Point cannot distinguish indoors and outdoors. In this paper, we implement extraction method of Stay Point in which specify the GPS log of users and extraction of Stay Point at indoors only. Stay Point(nearSP) specifies the nearest GPS log of users from generated Stay Point by conventional extraction method. And, Stay Point(indoorSP) specifies the GPS log of users that user get into the building. Our experimental results, accuracy of Stay Point is improved, and capacity of output data decrease than Conventional extraction method. Also, we were able to distinguish Stay Point of indoors and outdoors.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.257-268
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• 2023

Sea ice plays an important role in Earth's climate by regulating the amount of solar energy absorbed and controlling the exchange of heat and material across the air-sea interface. Its growth, drift, and melting are monitored on a regular basis by satellite observations. However, low-resolution products with passive microwave radiometer have reduced accuracy during summer to autumn when the ice surface changes rapidly. Synthetic aperture radar (SAR) observations are emerging as a powerful complementary, but previous researches have mainly focused on winter ice. In this study, sea ice drift tracking was evaluated and analyzed using SAR images and tracker with global positioning system (GPS) during late summer-early autumn period when ice surface condition changes a lot. The results showed that observational uncertainty increases compared to winter period, however, the correlation coefficient with GPS measurements was excellent at 0.98, and the performance of the ice tracking algorithm was proportional to the sea ice concentration with a correlation coefficient of 0.59 for ice concentrations above 50%.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.7
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• pp.865-870
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• 2004

Development of new information and traffic technology causes fast-growing in the field of information-based system. At recent, development of LBS(Location Based Service) makes a remarkable growth of industry as GPS(Global Positioning System) becomes wide-spread and location information becomes more important. However, there is a problem like infringement of privacy when location information is used improperly［1］. In this paper, LBS platform is proposed in order to prevent infringement of privacy. To implement, we classify user path as pattern in a zone of user life. Thereupon, location information is provided according to user' specific situation.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.7-13
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• 2008

본 연구에서 개발한 노변 영상(roadside image) 취득 시스템은 효율적으로 도로 시설물들을 관리하기 위함이다. 복잡하고 긴 구간의 도로에 존재하는 도로 시설물을 인력을 사용하여 조사하기에는 많은 시간과 비용이 소요된다. 도로를 따라 움직이는 차량을 이용하는 경우에는 적은 인원과, 단시간에 노변에 설치된 시설물 등의 현황과 상태를 조사 할 수 있으며 도로 주변의 다양한 정보를 알 수가 있다. 또한, 차량에 장착된 GPS/INS 통합시스템을 사용하여 해당 영상의 정확한 위치 정보를 획득 할 수 있다. 그러나 선명한 영상을 취득하기 위해서 야외의 다양한 조건을 만족시키는 카메라와 렌즈의 선정이 중요하며, 이에 따른 동기화 장치(synchronization device)와 영상 획득 프로그램의 개발이 필요하다. 본 논문에서는 경기도 고양시를 대상으로 시험을 실시하였으며, 현재 시판되고 있는 최신의 다양한 종류의 카메라와 렌즈를 차량에 장착한 후 영상을 취득하여 연구에 적합한 하드웨어를 선정하였다. 또한 동기화 장치를 사용하여 DMI(Distance Measuring Instrument)에서 발생되는 트리거 신호를 입력받아 일정한 거리마다 영상을 취득하는 S/W와 동기화 장치의 성능을 테스트하였다. 취득된 노변 영상의 위치 정확도를 테스트하기 위해 DGPS 방법을 이용하여 후처리 하였으며, 레벨 2수준의 교통주제도에 차량의 이동궤적과 도로의 선형을 중첩하여 육안으로 비교 분석하였다. 취득된 노변 영상을 분석하여 지상 모니터링 분야에서 도로 주변 시설물의 변화 탐지에 이용이 가능한 대상 시설물 목록을 선정하였으며 매우 효율적으로 도로의 유지관리에 활용이 가능할 것으로 기대된다.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.142-150
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• 2008

In order to ensure the individual and mutual performances among the telemetry system, tracking system, flight termination system, GPS, and inertial navigation & guidance system which are installed in the KSLV-I 2nd stage and ground equipment of the Naro space center, flight test using a light airplane is required. Since the high degree of test efficiency is fulfilled through the minute plan and analysis about selection of the equipment which are applicable to the test, harness, operation strategy, and antenna installation. KSLV-I communication environment and flight profile should be precisely taken into account during the flight test. In this document, overall aspect of the KSLV-I 2nd stage equipment specification, a rack for the installation, harness, the airplane specification, and flight route which are required for the effective flight test are presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.991-1000
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• 2019

The flying-disc game has started since 1940. It has been spreading rapidly in Korea since 2007, mainly in elementary schools. Additionally, as sports science has been developed, research on flying discs has been continued to build a monitoring system for technological improvement and efficiency. In this paper, we acquire information on the user's flying-disc using 9-axis motion sensor and GPS. Then we propose a method for wireless transmission using Bluetooth 5.0. Specifically, the HW platform was designed and implemented not only to monitor a real-time data but also to compare and analyze rotational speed, flight trajectory, and a count of disc rotation through post-processing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.258-259
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• 2021

Forest lodge are divided into forest resources, auxiliary facilities, and users, and are constantly being used along with well-being culture. In addition, attention to the safety of users is also required, and this study aims to study how users evacuate within a short time (golden time) in situations of natural disasters that may occur in forests. In order to search for the current location of the user and find the best evacuation route, 3D scans of the entire forest lodge(forest resources, auxiliary facilities, etc.) are performed, and the optimal trajectory to the evacuation site is found through recognition of the current location. It is believed that it is possible to provide a quick evacuation guide through a mobile device with gps.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.157-167
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• 2010

Unscented Kalman filter based backward filter is derived and the positions from extended Kalman filter, unscented Kalman filter, and extended Kalman smoother are compared and analyzed through a simulation test. Considering the poor GPS signal reception, the simulation is performed under the assumption of only the start and end points of the trajectory, composed of 4 curves and 5 straight sections in the area of $40m{\times}40m $, are known. The test shows that the smoothers generate much better positioning results of 8~9m improvement compared to those from the forward filters. For the comparison between the smoothers, the analysis is performed separately for the curves and straight segments. In both cases, the unscented Kalman smoother generates better positioning error; 10cm and 23cm improved positioning results in straight segment and curves, respectively.