• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.248-251
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• 2010

Smart Phones from a PC using the Internet using a multimedia data service provides a scalable and user convenience is provided in the form of an application. Wired and wireless communications, especially with the reduction of royalty free WiFi or the Internet to download the application program on the PC you're using on the Smart Phone. In this paper, the location API in Android-based Smart Phone, using GPS coordinates identified in the latitude and longitude coordinates can be transferred to the server, Android Smart Phone to know the possibility of retracing the location. You are smart trace back information from the user application program design, development, and real-time GPS location signals combined backtrack to read the GPS location in Google Earth application is to study the trace back.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.133-140
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• 2015

In this paper, a roll angle estimation method of a rolling airframe using a low grade GPS and a roll rate gyro is proposed. The strength of the received signal of the GPS antenna attached on the rolling airframe is maximized when the GPS satellite is placed on the plane determined by the x-axis of the rolling airframe and the GPS antenna axis. Under the assumption that the x-axis of the rolling airframe is coincident with its velocity vector, the roll angle of the rolling airframe is calculated from the relative position vector of the satellite to the GPS when the GPS signal strength becomes maximum. The Kalman filter combined with a roll rate gyro is introduced to increase the determination accuracy of the roll angle. The performance of the proposed method is verified via 6-DOF simulations.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.3
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• pp.283-292
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• 2005

After USA removed the Selective Availability (SA), Global Positioning System (GPS) has monopolized the world market and other countries have been depended on GPS, absolutely. So the other countries, Russia, European Community (EC) and Japan, which apprehend to monopolize in technical and strategic parts, are developing the next generation GNSS including GLONASS Galileo and JRANS. And the countries are planning to provide the another GNSS. This research has focused on the next generation GNSS system based on GPS and Galileo system with developing a GNSS simulation software, named as GlMS2005, which generates and analyzes satellite constellation and measurements. Based on the software, a variety of simulation tests have been carried out to recognize limits of GPS-only system and potential benefits of integrated GPS/Galileo positioning in terms of satellite geometry strength and solution accuracy.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.403-409
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• 2015

The Quasi-Zenith Satellite System (QZSS), a dedicated regional Japanese satellite system currently under development, was designed to complement the performance of the Global Positioning System (GPS). The high elevation angle of the QZSS satellite is expected to enhance the effectiveness of GPS in urban environments. Thus, the work described in this paper, aimed to investigate the effect of QZSS on GPS performance, by processing the GPS and QZSS measurements recorded at the Bohyunsan reference station in South Korea. We used these data, to evaluate the satellite visibility, carrier-to-noise density (C/No), performance of single point positioning, and Dilution of Precision (DOP). The QZSS satellite is currently available over South Korea for 19 hours at an elevation angle of more than 10 degrees. The results showed that the impact of the QZSS on users' vertical positioning is greatest when the satellite is above 80 degrees of elevation. As for Precise Point Positioning (PPP) performance, the combined GPS/QZSS kinematic PPP was found to improve the positioning accuracy compared to the GPS only kinematic PPP.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.177-182
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• 2013

In this paper, printed antenna which can be applied to a built-in wireless module of the security controller operating at global positioning system(GPS) L1 frequency band(1.575GHz) is proposed. The proposed antenna is basically composed of a microstrip patch antenna with inserting feed. In particular left and right slots which are respectively asymmetric are used for impedance matching, whereas slot with one open-end and shorting point are used on the bottom plane to set operating frequency and enhance bandwidth. It is observed at the desired GPS L1 frequency band that the radiation efficiency and gain of the proposed antenna are 90% and more than 4.8dBi respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.6
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• pp.446-455
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• 2001

In this paper, the precise synchronized clock generator using GPS receiver is presented. The GPS receiver provides a synchronized IPPS signal which guaranties a reliable standard time mark. This signal allows us to do time synchronization and correct the time step. We designed and implemented the precise synchronized clock generator based on DPLL in order to generate a high-resolution clock from a low-cost inaccurate oscillator with ALTERA FLEX EPM6016TC144-3. We also implemented a hardware unit and proved that the unit provides 1MHz clock output which had a high resolution and accuracy when it was combined with GPS receiver.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1636-1645
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• 2016

In navigation systems that use collected trajectory for routing, the number and diversity of trajectory data are crucial despite the infeasible limitation which is that all routes should be collected in person. This paper suggests an algorithm combining trajectories only by collected GPS data and generating new routes for solving this problem. Using distance between two trajectories, the algorithm estimates road intersection, in which it also predicts the correlated direction of them with geographical coordinates and makes a decision to combine them by the correlated direction. With combined and generated trajectory data, this combination way allows trajectory-based navigation to guide more and better routes. In our study, this solution has been introduced. However, the ways in which correlated direction is decided and post-process works have been revised to use the sequential pattern of triangles' area GPS information between two trajectories makes in road intersection and intersection among sets comprised of GPS points. This, as a result, reduces unnecessary combinations resulting redundant outputs and enhances the accuracy of estimating correlated direction than before.

• 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.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.3 s.37
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• pp.47-53
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• 2006

In this contribution, an integration of seamless navigation system for the pedestrian is introduced. To overcome the GPS outages in various situations, multi-sensor of GPS, INS, electronic barometer and compass are considered in one Extented Kalman filter. Especially, the integrated system is designed for low-cost for the practical applications. Therefore, a MEMS IMU is considered, and the low quality of the heading is compensated by the electronic compass. In addition, only the pseudoranges from GPS measurements are considered for possible real-time application so that the degraded height is also controlled by a barometer. The mathematical models for each sensor with systematic errors such as biases, scale factors are described in detail and the results are presented in terms of a covariance analysis as well as the position and attitude errors compared to the high-grade GPS/INS combined solutions. The real application scenario of GPS outage is also investigated to assess the feasible accuracy with respect to the outage period. The description on the current status of the development and future research directions are also stated.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.231-235
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• 2003

실시간 동적 GPS 측위를 이용한 해저수심측량은 GPS 수신기가 이동중인 상태에서 신호단절 없이 연속적인 수심측정이 가능하며 등수심도와 등고선 제작에 정확한 위치를 결정할 수 있고, 음향측심기는 발사파와 수신파의 도달시간을 측정하여 수심을 관측할 수 있기 때문에 실시간으로 정확한 3차원 측량이 가능하다. 본 논문에서는 해안지역에 대한 지형 분석을 하기 위하여 기준점에 대한 정지관측을 실시하여 좌표변환계수를 산출하고, 이로부터 실시간 동적 GPS 측량과 음향측심기를 이용하여 해운대 해수욕장과 해안을 관측하였다. 1:1,200 축척의 수치지도에서 추출한 수치표고모델에서의 체적은 97953.9 ㎥이며, 실시간 동적 GPS와 음향측심기를 이용하여 추출한 수치표고모델에서의 체적은 95994.9 ㎥로 나타났다. 이는 수치지도에서의 체적과 측량결과의 체적이 단지 2.0%정도로 나타나 실시간 동적 GPS와 음향측심기의 결합에 의한 해저수심측량이 매우 성공적임을 알 수 있었다.