• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.903-905
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• 2012

Recent research on Augmented Reality is Actively expand and Augmented reality feature added to the social network system (Social Network System) has become a necessity. In this paper, GPS-based Augmented Reality System for Social Network is introduced, is proposed. This system can add recent check-in friends in facebook by automatically to synchronizing the location coordinate, and it could also adding location coordinates system is represented in a real-world environment by AR, is Marker-based AR system that was Commonly used AR system is a huge cost by handheld devices in processing and storage space, the disadvantages of the marker-based AR systems can be solved by using Location-based AR applications. Therefore, the proposed GPS-based Augmented Reality System for Social Network, automatically searches for the optimal speed for Wifi and 4G network to iOS Hand AR system was desired in future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.4
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• pp.367-380
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• 2011

This paper has focused on deriving a GPS based geodetic network adjustment strategy to continuously determine coordinate sets of the national geodetic control points. After domestic literature review on the topic and overseas case studies about countries that recently reformed their geodetic infrastructure have been carried out, a simplified geodetic network consisting of two layers, namely GPS active and passive network, has been proposed to maximize effectiveness of the network adjustment through reducing the number of the passive points. Furthermore, a GPS data processing and network adjustment procedure has been derived to support the continuous management scheme. While a scheme for the active layer adopts a sequential least squares adjustment based on a multi-baseline, that of the passive layer employs a multi-session adjustment technique with respect to 3-dimensional baseline vectors. Finally, experimental adjustment against a network comprising 24 active and 6,900 passive stations has been performed to demonstrate the efficiency and the effectiveness of the proposed method.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.55-60
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• 2003

As the distance between GPS rover station and GPS base station increases, more decorrelated positioning errors limit the ability for PDGPS(Precise Differential GPS). The objective of this paper is to present the improvement of using VRS(virtual reference station) based on multiple GPS reference station network to single reference station for static positioning in post-processing mode. For this, the VRS observations from GPS observations of real reference stations are derived by using Web service in post-mode. The coordinates of check point post-processed by 27 kind of VRS observations compared with the known ones.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.762-767
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• 2013

Recently, researches on augmented reality(AR) are actively being conducted, and on addition of AR in social network system has become a necessity. In this paper, we propose GPS-based AR system for social network. This proposed system adds the recent check-in coordinates by automatically synchronizing a friend list in facebook and represents those added location coordinates in a real-world environment by using AR. Marker-based AR system that was commonly used by existing users consumes too much storage space and processing frequency for driving handle devices. But, location-based AR application can solves the disvantages of the standard marker=based AR system. Therefore, this proposed system allows an user with iOS hand devices to use GPS-based AR system by automatically searching the optimal speed for wifi and 4G. This will improve social network service.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.55-63
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• 2013

Network-RTK GPS positioning technique based on national CORS(Continuous Operating Reference Station) and wireless internet access as like VRS and FKP was developed to overcome the limitations of traditional RTK technique. In Korea, NGII(National Geographic Information Institute) provides network-RTK service based on 51 CORS and mobile internet network. The purpose of this study is the accuracy evaluation of the height determined by GPS VRS technique based on network-RTK, So, in this study GPS VRS positioning was accomplished through 1st level BM line located at Sancheong~Jinju and $2^{nd}$ level BM line located at Geochang~Sancheong and the average error of the each BM line was calculated as 2.15cm and 1.80cm respectively. This result shows that GPS VRS height positioning can be used in $3^{rd}$ and 4th public BM leveling and also work regulation is needed to apply the GPS VRS height positioning.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.251-254
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• 2006

A precise real-time method of using the IGS ultra rapid products (IGU) and the GPS broadcast ephemeris to calculate the VRS orbit corrections was presented here which was suited for GPS/VRS reference station network based positioning. Test data acquired from both the SGRSN (Sichuan GPS Reference Station Network) and SCIGN (Southern California integrated GPS network) were used to evaluate the performance of the modeling techniques. The new method was proven to be more precise and reliable compared with the existing conventional network-based orbit error interpolation method. It was shown that 0.004ppm relative accuracy was reached, namely the influence from the orbit bias for the RTK positioning within 100km area can be of sub-millimeter level.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.77-85
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• 2013

Recently, location information based routing protocol has been studied to estimate end-to-end path in wireless ad-hoc network. This protocol assumes all nodes can get heir location information via GPS devices and floods only limited area with routing message through acquired location information. Therefore, this protocol has advantage that can reduce the number of routing message than the existing IP-based routing protocols. In addition, all nodes enabling this protocol must acquire their own location information to participate in the location-based routing. However, recent because of the miniaturization of sensor node, sensor node without GPS function has been launched. Therefore in case of the sensor node that does not know location information, it is impossible to participate in the ad hoc network configuration and location information based routing. In this paper, a virtual location information based routing scheme is proposed for wireless nodes without GPS function to be able to participate in location information based routing within ad hoc network environments consisting of wireless nodes with GPS function and wireless nodes without GPS function. Therefore, the proposed protocol has the advantage that a wireless node without a GPS function is able to participate in ad hoc network configuration and the location information based routing.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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• pp.221-233
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• 2016

This paper deals with performance assessment of the kinematic network-based GPS positioning technique with a view to using it for ellipsoidally referenced bathymetric surveys. To this end, two field trials were carried out on a land vehicle and a surveying vessel. Single-frequency GPS data acquired from these tests were processed by an in-house software which equips the network modeling algorithm with instantaneous ambiguity resolution procedure. The results reveals that ambiguity success rate based on the network model is mostly higher than 99.0%, which is superior to that of the single-baseline model. In addition, achievable accuracy of the technique was accessed at ${\pm}1.6cm$ and 2.7 cm with 95% confidence level in horizontal and vertical component respectively. From bathymetric survey at the West Nakdong River in Busan, Korea, 3-D coordinates of 2,011 points on its bed were computed by using GPS-derived coordinates, attitude, measured depth and geoid undulation. Note that their vertical coordinates are aligned to the geoid, the so-called orthometric height which is widely adopted in river engineering. Bathymetry was constructed by interpolating the coordinate set, and some discussion on its benefit was given at the end.

• Journal of Internet Computing and Services
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• v.2 no.5
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• pp.49-58
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• 2001

Mobile positioning measurement is the most important technology for Location Based Services in the cellular networks. Generally, we are expecting to use GPS to guarantee high accuracy of the mobile position, A CDMA network-based technique for the Mobile Station position calculation needs to be implemented in the cdma2000 network whether the handsets have GPS or not, The most reliable methods of the network-based location technologies are based on the estimation of time of signal traveling between MS and B18 in a network whose coordinates are identified, Other signal parameters such as the power of the received signal and the signal arrival direction cannot be used as main data for a location system because adoption of only the signal parameters will not meet the FCC requirements, In practice, the estimates of the time of signal propagation between MS and BTS always have errors resulting from low-resolution power of measurements and multi path signal propagation, This paper describes the combined network-based location technology in the cdma2000 1× necessary to meet US FCC requirements. The issues of a calibration table and statistic processing based on the pilot strength as well as combined network-based location technologies(TOA/ TDOA) will help to achieve higher location accuracy than specified in the US FCC Rule.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.167-173
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• 2011

This paper analyzes the procedure of calculating how the results of national control points (triangulation points), based on Bessel datum, have been transformed into those of KGD2002, based on the world geodetic system. GPS and EDM data observed from 1974 to 2008 were used for this purpose. A large-scale integrated GPS network was constructed to estimate the results of KGD2002 and new national control points about 12,000 were decided through multiple stages of data processing. The accuracy of these results is ${\pm}0.015m$ (95%) in the horizontal direction and ${\pm}0.030m$ (95%) in the vertical direction. The adjusted results verified by the construction of an integrated GPS/EDM network were compared with the results of KGD2002. In conclusion, the bulletin results are thought to be appropriate because the coordinate differences (RMSE) are ${\pm}0.0025m$ and ${\pm}0.008m$ in horizontal and vertical directions respectively.