• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.5
• /
• pp.160-172
• /
• 2018

The method of estimating a position using a GPS has been applied to various fields including a navigation system of an automobile. However, since it is difficult to measure GPS signals indoors, it is difficult to locate specific objects indoors such as a building or factory. To overcome these limitations, this study proposes a system for object location estimation based on Bluetooth5 for the management of materials in factories. The object position estimation system consists of a Bluetooth signal generator, a receiver, and a database server. A signal generator based on Bluetooth Low Energy(BLE) is attached to the material and a receiver is appropriately arranged inside the factory. In this study, we propose "Diagonal Survey Method", a 4 - axis survey algorithm using four receivers to reduce the error of existing trilateration method. The proposed algorithm showed good performance compared to the conventional trilateration and we verified the effectiveness of the proposed system and algorithm by performing the experiment by installing the system in the factory.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.9 no.2
• /
• pp.37-48
• /
• 1991

In this study, conventional network adjustment and combined network adjustment methods for single network adjustment methods for single network and centric combination network were compared by the analysis of root mean square error and standard error ellipse of observed points. It can be concluded from this study that for conventional surveying methods, the accuracy is in theorder of trilateration, traverse and triangulation, and for the case of combined surveying method, the accuracy is in the order of multilateration surveying, combined traverse and combined triangulation-trilateration surveying. And when establishing new control points, the accuracy can be improved by increasing redundant observations of centric combination network instead of using the single network. Also, in case of combined traverse surveying by adding observable laterals, accuracy level of trilateration could be achieved, and it was found that traverse is effective for large areas where sighting is easy, and combined traverse surveying is effective for urban areas where sighting is difficult.

• Journal of Internet Computing and Services
• /
• v.12 no.2
• /
• pp.19-28
• /
• 2011

Recently, ubiquitous computing and related technologies is more and more growing concern about. Depending on the trend, the moving object recognition and tracking research have been required in order to meet the diverse needs of the user. In the location-based services, one of the most important issues in the indoor environment is to provide location-aware services. In this paper, the effective algorithm to help estimate the position of moving objects in an indoor environment is proposed. We propose an algorithm that combined the existing trilateration measurement and the improved measurement of environmental adaptation scene analysis. The proposed indoor location estimation algorithm use the trilateration measurement when we have enough anchor in the line-of-sight environment. Otherwise that use measurement of environmental adaptation scene analysis. Consequently, the proposed algorithm has been improved the localization accuracy of a moving object as well as was able to reduce complexity of the algorithm.

• Journal of Korean Society for Geospatial Information Science
• /
• v.15 no.3
• /
• pp.41-49
• /
• 2007

In this study, the software to compute Bessel coordinates by trilateration adjustment was developed, and the software was used to determine coordinates of the cadastral control points over the southern Korean peninsula. The baseline measured by GPS was reduced to the distance on geoid surface by applying PNU95 geoid model, and the distance on geoid surface was reduced to the plane grid distance by applying scale factor of map projection of Bessel coordinates. Using the plane grid distance, Bessel coordinates of 32 CORS (Continuously Operating Reference Station) were computed by free adjustment at first, and then the coordinates of the cadastral control points were computed by joining the control points to adjacent CORS. The result shows a possibility of construction of highly accurate and consistent cadastral survey network with coordinate error less than 1ppm of distance, when newly computing the coordinates of the control points by using distances measured by GPS.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.4C
• /
• pp.254-264
• /
• 2011

In this paper, we propose two algorithm for improving the performance of wireless localization(Trilateration and Least Square) based on the range based approach method in indoor environment using RSSI for ranging distance. we propose a method to discriminate the case that has relatively large estimation errors in trilateration using Heron''s formula for the volume of a tetrahedron. And we propose the algorithm to process the discriminated types of distance using the absolute value calculated by Heron''s formula. In addition, we propose another algorithm for the case of which the number of anchor nodes larger than three. In this case, Residual Weighting Factor(RWGH) improves the performance of Least Square. However, RWGH requires many number of calculations. In this paper, we propose Iterative Weighted Centroid Algorithm(IWCA) that has better performance and less calculation than RWGH. We show the improvement of performance for two algorithms and the combination of these algorithm by using simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.493-496
• /
• 2011

Currently in the development of community wireless technology is gaining interest in location-based services and as a result, the importance of the location information is a growing trend. To calculate the location information is being suggested several ways, among them Trilateration is representative. Trilateration is three beacon nodes, the distance between the location in which you want to calculate with information. Beacon from a node to know where to get information when the distance between the obstacle and the distance error caused by the surrounding environment, which leads to the exact location can not be obtained. Currently due to distance error, location information has a variety of algorithms to reduce the error. However, a systematic analysis of these algorithms is not progress. This paper analyzes the location-aware technologies, and the error the distance of the location information to reduce errors in the various aspects of the algorithm for the systematic and empirical comparison was evaluated through the analysis.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.3
• /
• pp.448-458
• /
• 2020

Indoor positioning based on trilateration using common chord estimates location of a mobile subject by using intersection points between each circles which the radius is same as distance between the mobile subject and each radio-frequency transmitter. However, if the intersection points are not found due to error of the distance measurement, it causes failure of estimating the mobile subject's location. To prevent this case, numbers which is proportionate to radius of each circles, are temporarily added to each distances in order to lengthen radius of the circles. Although the estimated location includes error due to the radius extension, it is corrected again by the added value and distance from reference point. With introduction of the advanced correction algorithm, potential issues of existing trilateration such as failure of estimating location and distance measurement error will be minimized.

• Proceedings of the KIEE Conference
• /
• 2008.05a
• /
• pp.137-138
• /
• 2008

가스절연변압기(GITr)는 우수한 절연내력과 높은 신뢰성을 장점으로 가지고 있기 때문에 운전 시 유지 보수가 불필요하도록 설계목표를 정하여 제작되고 있지만, 제작과 운전 단계에서 치명적인 결함이 발생할 수 있고, 이러한 결함들은 전력기기 사고의 원인이 될 수 있다. 따라서 사고발생 전 단계에서 대규모 전력 사고의 발생 요인 중 하나인 전력기기 내부의 결함에 대한 상시 진단 및 원인 분석이 반드시 선행되어야 하며, 이와 같은 진단 분석 기법의 하나로 전력 기기의 내부 결함의 위치 판별에 대한 연구의 필요성이 절실히 요구되고 있다. 따라서 본 논문에서는 일반적으로 Cubicle 구조체 위치의 판별에 사용되는 기법 중 하나인 상변측정법(Trilateration)을 적용함으로써, GITr Mockup(170kV 급)의 세 개의 센서를 이용하여 결함에서 발생되는 부분방전 신호를 3차원적으로 분석하기 위한 연구를 위해 3개의 센서가 구성하는 평면상에 인위적 결함을 위치시켜 결함의 위치를 2차원적으로 분석하는 연구를 수행하여 약 5cm 오차 범위 내에서 결함을 판별하였다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.8
• /
• pp.1250-1256
• /
• 2017

In this research, a high-performance ultrasonic positioning system is proposed to track the positions of an indoor mobile object. Composed of an ultrasonic sender (mobile object) and a receiver (anchor), the system employs three ultrasonic time-off-flights (TOFs) and trilateration to estimate the positions of the object with an accuracy of sub-centimeter. On the other hand, because ultrasonic waves are interfered by temperature, wind and various obstacles obstructing the propagation while propagating in air, ultrasonic pulse debounce technique and Kalman filter were applied to TOF and position calculation, respectively, to compensate for the interference and to obtain more accurate moving object position. To perform tasks in real time, ultrasonic signals are processed full-digitally with a Zynq SoC, and as a software design tool, Vivado IDE(integrated design environment) is used to design the whole signal processing system in hierarchical block diagrams. And, a hardware/software co-design is implemented, where the digital circuit portion is designed in the Zynq's fpga and the software portion is c-coded in the Zynq's processors by using the baremetal multiprocessing scheme in which the c-codes are distributed to dual-core processors, cpu0 and cpu1. To verify the usefulness of the proposed system, experiments were performed and the results were analyzed, and it was confirmed that the moving object could be tracked with accuracy of sub-cm.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.13 no.1
• /
• pp.13-20
• /
• 1995

Error analysis is important in horizontal positioning. In case of error analysis, standard error ellipse is generally used to establish the precision regions, but it will be replaced by 95% confidence ellipse. It is more effective than standard error ellipse in resection for measured procedures and establishment for criterias of relative error. Therefore, In this paper deals with analysis of application to 95% confidence ellipse in horizontal positioning. This study deals with error analysis of plane trilateration network which are various types of control point. also, this paper have studied for theory of error analysis in order to using least square adjustment. Thus, This paper's conclusion are as follows; 95% confidence ellipse could be used to establish of specification in korea, also, it is possible for us to predesign for optimum surveying network by 95% confidence ellipse.