• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.5 no.1
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• pp.66-72
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• 1987

It is well known that a triangulateration net is superior to a trilateration net or triangulation net in a same configuration. In general, to explain this nature is not easy because the large residuals and reference variance are revealed in the adjustment of a heterogeneous network. In this paper the precision and the reliability of network are discussed, and the considerations of simultaneous adjustment are covered A practical example shows that the concept and criteria of reliability give better estimate than the precision in heterogeneous network.

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

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.473-480
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• 2013

In this paper, location recognition algorithm is developed to improve the accuracy using improve Trilateration. The location recognition algorithm is first calculate the location refer to the measured signal power. Error can be occurred when measure distance with arranged node in specific location. If the distance data is received from node (receiver, coordinator), Node selected for location calculation is defined through section. If the distance data is received from node (receiver, coordinator), Node selected for location calculation is defined through section. Second, we apply algorithm of section filtering. If there are 4 sections in node, we consider 1 section to 6 location recognition coordinates. A special characteristic drawback of RF is that the actual distance is actually farther than the calculated received distance data. This is error is incurred when the signal strength increases. We reduce the location recognition error by applying an improved algorithm as secondary after filtering primary through section filtering.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.3-13
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• 2008

The coordinate of cadastral control points located over the area of different surveying origins is computed in a single surveying origin by trilateration adjustment of GPS baseline measurements. In every different surveying origins, well-matched control points are selected and mutually coinciding coordinates are computed by free network adjustment. Then, the coordinate of the other control points over the area is computed by joining these points to the adjusted points. In practice, by using 18 points of Gari, 17 points of Gyeyang, and 33 points of Central origin in Incheon, the coordinates of total 68 points in every surveying origin are computed. Between the points of different surveying origins, it is found that there are quantitative differences in azimuth and scale factors and the approximate point coordinate of other surveying origins is calculated by correcting the scale and azimuth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.7
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• pp.852-860
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• 2019

In this paper, we proposed a new trilateration technique based on exponential moving average (EMA) filter with adaptive signal model which enhances accuracy of positioning system even if the RSSI changes randomly due to movement of obstacles or blind node in indoor environment. In the proposed scheme, three fixed transmitters sent out the signal to blind node. The transmitter decides the location of the blind node based on RSSI and it estimates the cause of RSSI fluctuation which is interference of obstacle or movement of blind node. When the path between blind node and transmitter has become NLOS path because of obstacles, the transmitter ignores the measured RSSI in NLOS path and replace estimated RSSI in LOS environment. In the other case, the transmitter updated the new RSSI to represent of movement of blind node. The proposed scheme has been verified on a ZigBee testbed and we proved the improved positioning accuracy compared to the existing indoor position system.

• Journal of Cadastre & Land InformatiX
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• v.54 no.1
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• pp.103-115
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• 2024

Trilateral adjustment can complement the problem of transforming cadastral maps into World Geodetic Coordinate system. First, it is possible to determine adjusted coordinate of common points that match each other over a wide area. Second, calculations that focus on specific points can be performed. Third, a solution that maintains the shape of the regional network can be obtained through constraints. Thus, the point coordinates can be determined appropriately for the survey system. In addition, heterogeneous survey results that span regions with different coordinate origins can be calculated on a single origin coordinate. This improves the efficiency of the workflow in tranforming cadastral maps into World Geodetic Coordinate System.

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

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.2
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• pp.79-87
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• 1993

Executing various constructions and national land planning, it has rised importance how to acquire 3-dimensional geographical information efficiently. In conjunction with this, the concerned parties are interested in the accuracy of GPS positioning and applications. This study suggest the efficiency and possibility to apply geographical information construction by kinematic GPS surveying as comparing kinematic GPS results with triangulation, trilateration and static GPS results. In this study, we try to compare static with kinematic and can determine 3-D positions with difference of 6 mm in distance, 2"/10,000-4"/10,000, 20 cm in latitude, longitude and height at local area. In addition, difference from conventional surveying is about 1"/l0,000-3"/10,000 in horizontal. Therefore it is expected to apply kinematic GPS to make out topographic map and to construct data base associated with GIS.associated with GIS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.3 no.2
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• pp.48-62
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• 1985

A method for the free network adjustment is proposed, based on the application of generalized inverse matrix (g-inverse). If the network adjustment is executed according to the solution with parameters, especially when all coordinates are considered as parameters to keep unity strength, the matrix of normal equation will be singular. This paper discusses the problem of singular matrix and the analysis of accuracy between conventional method and the free network adjustment of trilateration. In case of the adjustment, the RMS errors of adjusted X, Y coordinates are increased to 35.6% in a polygon, central-point figure, and 50.5% in a quadrilateral. In the elements of error ellipse, the RMS errors are decreased by $\pm$24.5% (a) and $\pm$5.0 % (b) in the polygon, $\pm$42.6% (a) and $\pm$49.2% (b) in the quadrilateral. Introduction of free network adjustment, therefore, could be applied to improvement of relative accuracy in the horizontal positioning.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.601-608
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• 2023

Mobile robots are widely used in industries because mobile robots perform tasks in various environments. In order to carry out tasks, determining the precise location of the robot in real-time is important due to the need for path generation and obstacle detection. In particular, when mobile robots autonomously navigate in indoor environments and carry out assigned tasks within pre-determined areas, highly precise positioning performance is required. However, mobile robots frequently experience data missing in wireless communication environments. The robots need to rely on predictive techniques to autonomously determine the mobile robot positions and continue performing mobile robot tasks. In this paper, we propose an extended Kalman filter-based algorithm to enhance the accuracy of mobile robot localization and address the issue of data missing. Trilateration algorithm relies on measurements taken at that moment, resulting in inaccurate localization performance. In contrast, the proposed algorithm uses residual values of predicted measurements in data missing environments, making precise mobile robot position estimation. We conducted simulations in terms of data missing to verify the superior performance of the proposed algorithm.