• Journal of Platform Technology
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• v.11 no.5
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• pp.97-103
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• 2023

Unlike GPS, which is an outdoor positioning technology that is universally and uniformly used all over the world, various technologies are still being developed in the field of indoor positioning technology. In order to acquire accurate indoor location information, a standard of representative indoor positioning technology is required. Recently, indoor positioning technology is expanding into the Real Time Location Service (RTLS) area based on high-precision location data. Accordingly, a new type of indoor positioning technology is being proposed. Thanks to the development of artificial intelligence, artificial intelligence-based indoor positioning technology using wireless signal data of a smartphone is rapidly developing. At this time, in the process of collecting data necessary for artificial intelligence learning, data that is distorted or inappropriate for learning may be included, resulting in lower indoor positioning accuracy. In this study, we propose a data preprocessing technology for artificial intelligence learning to obtain improved indoor positioning results through the refinement process of the collected data.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.130-144
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• 2023

Recently, various positioning technologies are being researched based on signal-based positioning and image-based positioning to obtain accurate indoor location information. Among these, various studies are being conducted on image positioning technology that determines the location of a mobile terminal using images acquired through cameras and sensor data collected as needed. For video-based positioning, a method of determining indoor location is used by matching mobile terminal photos with virtual landmark images, and for this purpose, it is necessary to build indoor spatial information about various landmarks such as billboards, vending machines, and ATM machines. In order to construct indoor spatial information on various landmarks, a panoramic image in the form of a road view and accurate 3D survey results were obtained through c 13 buildings of the Electronics and Telecommunications Research Institute(ETRI). When comparing the 3D total station final result and the terrestrial lidar panoramic image coordinates, the coordinates and distance performance were obtained within about 0.10m, confirming that accurate landmark construction for use in indoor positioning was possible. By utilizing these terrestrial lidar achievements to perform 3D landmark modeling necessary for image positioning, it was possible to more quickly model landmark information that could not be constructed only through 3D modeling using existing as-built drawings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1459-1467
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• 2011

Cell-ID based positioning solution is cheaper and easier to implement than other wireless positioning solutions. However, its accuracy is relatively low. So we propose a novel approach to improve its accuracy. Our approach uses the probability that an MS will connect to each of BSs among several BSs to which an MS can access in a pico-cell network, and Cell-ID based positioning method is applied. The simulation result shows that performance of the proposed approach is improved compared to the other positioning solutions.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.4
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• pp.359-366
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• 2002

To survey satellites using only GPS can sometimes cause an impossible situation due to the many different geographical conditions as city cannon and obstacles. Although the GLONASS satellite system does not have the ability to survey itself accurately since it currently lacks of the number of usable satellites, it is able to bridge the gap when combined with GPS. This research used the GPS receiver to perform four analyzing methods to bring out the independent surveying method of GPS and combined surveying method of GPS and GLONASS(4 methods - number of satellites able to receive, precision of raw data, standard deviation from known point and RTK surveying). The result of test surveying satellites showed that 11 hours were possible to measure a minimum of 4 satellites when using an independent surveying method and 4 hours in unified surveying method in a month. Also, the precision of raw data using GPS and GLONASS surveying is 0.08~l.8m better than the GPS surveying in standard deviation. The deviation of known points by GPS and GLONASS also showed better accuracy by 3~l1mm. The RTK showed the range of differences in deviation of survey by leaning towards the GPS independent survey in Northing coordinate and leaned towards the Easting coordinate when GPS and GLONASS were combined. Nonetheless, it can't be said that the unified method is better, because it has limits to its capability.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.573-578
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• 2010

Precise determination of satellite positions is necessary to improve positioning accuracy in GNSS. In this study, GLONASS orbits were predicted from broadcast ephemeris using the 4th-order Runge-Kutta numerical integration method and their accuracy dependence on the integration step and the integration time was analyzed. The 3D RMS (Root Mean Square) differences between the results from I-second integration step and 300-second integration step was about 3 cm, but the processing time was one hundred times less for the I-second integration time case. For trials of different integration times, the 3D RMS errors were 8.3 m, 187.3 m, and 661.5 m for 30-, 150-, and 300-minutes of integration time, respectively. Though this integration-time analysis, we concluded that the accuracy gets higher with a shorter integration time. Thus we suggest forward and backward integration methods to improve GLONASS positioning accuracy, and with this method we can achieve a 5-meter level of 3-D orbit accuracy.

• The Magazine of the IEIE
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• v.38 no.1
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• pp.68-74
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• 2011

이동단말기의 위치기반서비스가 핵심 무선인터넷서비스로 부상하고 있다 위치기반서비스는 정확하고 신뢰성 있는 단말기의 위치추정을 기반으로 한다. 이를 위하여 현재 GPS가 광범위하게 사용되고 있지만 기술적인 한계점으로 인하여 최근 RF 무선신호를 이용하는 RF 무선측위기술이 대체기술로 대두되고 있다. 이에 따라 최근 타 RF 기술에 비해 측위기술과 네트워크 인프라의 경쟁력을 보유한 WiFi 기반 무선측위기술이 부각되고 있다. 국내 또한 WiFi 기반 무선측위에 대한 연구를 활발히 수행 중이지만 시스템 개발에 따른 해외특허의 회피전략 또한 중요 관심사이다. 따라서 본고는 국내 위치기반서비스에 대한 국가 정책 및 사업화 방향의 전략결정에 유용하게 할용 될 수 있도록 WiFi 기반 무선측위기술의 기반기술 및 요소기술들을 정의하고 출원특허들의 선행조사와 분석을 통하여 이들 기술들에 대한 출원특허들의 기술계통도를 작성한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.199-207
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• 2003

In the study, the open area keeping a few visible satellites and the urban area covered with the high building, an electric pole were chosen far evaluation of accuracy of satellite positioning. First, suggest the validity of GPS/GLONASS, TS/RTK-GPS, and compared the accuracy with that of the classical surveying method. As a result, In static relative surveying, the difference of between the known cadastral supplementary control station and that of the acquired is 0.000∼.0006m in GPS alone, GPS/GLONASS, and In the RTK-GPS/TS, 0.010∼0.077m on the non-ambiguity fixed solutions in the urban area 0.008∼0.078m in the open area. it proved to be valid because it is within the allowed connecting errors, i.e 12cm on the baseline of loom in l/l,200 cadastral map.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.38-44
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• 2019

This paper proposes fingerprint-based positioning methods which can be used in a magnetic resonant wireless power transfer(WPT) system and verifies their performance. A new receiver coil with small orthogonal auxiliary coils is proposed to measure magnetic field signals in three axial directions. The magnitude and phase characteristics of the three-axis electromotive force can be obtained by using the proposed coil. To predict a position with the measured values, we propose a lookup table-based method and linear discriminant analysis-based method. For verification, the proposed methods are applied to predict 75 positions of the 6.78 MHz WPT system, and the performances such as accuracy and computation time are compared.

• Information and Communications Magazine
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• v.32 no.8
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• pp.38-44
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• 2015

본고에서는 자동차의 자율주행이라는 최종의 목표를 위해 필요한 여러 가지 필수 기술 중 하나라고 할 수 있는 자동차의 자기 위치 인식을 위한 측위 기술에 대해 소개하고 그와 관련된 여러 연구 개발 동향을 살펴보고자 한다. 또한, 지능형 운전보조 시스템(ADAS, Advanced Driver Assistance System)에서 필수적인 고정밀 전자 지도(High Precision Map)가 자동차의 자기 위치 인식 정확도 향상에 어떤 방법으로 활용되는 지에 대해서도 알아 보고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.199-200
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• 2017

In order to meet the international performance requirements for eLoran testbed operation, it is necessary to measure ASF (Additional Secondary Factor) of vessel's route as well as differential correction and the provision using differential Loran (dLoran) station operation. According to HEA (Harbor Entrance and Approach) performance of the IMO, the position accuracy should be within 10meters. Therefore this paper presents the possibility to meet the position accuracy of the IMO HEA through simulation results.