• Journal of Positioning, Navigation, and Timing
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• v.7 no.4
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• pp.217-226
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• 2018

According to the Korea Coast Guard's maritime disaster statistics (Korea Coast Guard 2017, Korean Statistical information Service 2018), an average of 2,140 marine accidents occurred every year for the past 6 years and the number of accidents is increasing every year. Among them, maritime accidents of fishing vessels are the most frequent, and recently accidents involving fishing boat and leisure vessels are rapidly increasing as well. In particular, the number of accidents involving leisure vessels increased to about one-third of the accidents of fishing vessels, and emergency rescue requests are increasing every year accordingly. However, the number of crash accidents involving users of small vessels and marine leisure activities are increasing because of the difficulties of installing navigation equipment and electronic navigation charts. Recently, the demand for precise positioning using mobile devices is increasing in the fields of maritime safety, piloting support, and coastal survey. Although various applications of smart devices provide location-based services for users, the measurement results are discontinuous when using the position coordinates of the National Marine Electronics Association (NMEA) calculated by smartphone. Recently, Google announced that they will provide GPS raw data to developers from Android 7.0 Nougat. As a result, developers have an opportunity to receive precise carrier phase and code measurements to make more accurate positioning according to the performance of Android devices. This study analyzed GPS positioning performance using Android devices, and compared and analyzed the positioning performance at sea with high-performance GPS receivers.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.514-519
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• 2017

In this paper, the pseudorange-based GPS performance using the Android's raw measurements is compared with NMEA. In order to compare the performance between the two different implementations, we used Nexus 9 tablets and collected the raw measurements and NMEA data using the GNSS logger application provided by Google. To verify the performance of the final coordinates calculated, the VRS was used as the reference coordinate and compared with the NMEA results. The resulting horizontal, vertical, and 3D RMS errors of the pseudorange-based GPS using the Android's raw measurements are 3.05, 3.82, and 4.97 m, respectively, which correspond to 32% horizontal, 65% vertical and 49% 3D performance improvement compared with NMEA.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.279-286
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• 2022

In this paper, we designed a software library that produces integrated Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) navigation information using the raw measurements provided by the GNSS chipset, gyroscope, accelerometer and magnetometer embedded in android smartphone. Loosely coupled integration method was used to derive information of GNSS /INS integrated navigation. An application built in the designed library was developed and installed on the android smartphone. And we conducted field experiments. GNSS navigation messages were collected in the Radio Technical Commission for Maritime Service (RTCM 3.0) format by the Network Transport of RTCM via Internet Protocol (NTRIP). As a result of experiments, it was confirmed that design requirements were satisfied by deriving navigation such as three-dimensional position and speed, course over ground (COG), speed over ground (SOG), heading and protection level (PL) using the designed library. In addition, the results of this experiment are expected to be applicable to maritime navigation applications using smart device.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.329-334
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• 2013

A positioning based service uses one's position information with GPS. This application also use the position based characters and change the smart phone to the vibration mode at the registered position. If the user register some places to be vibrated in the smart phone, the smart phone will be automatically changed to the vibration mode as the registered position is same with the position of GPS in the smart phone. If the smart phone is being leaving some distance from the position, the phone will be released from the vibration mode. Therefore, this paper propose aims for intelligent smart phone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.50-56
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• 2014

Recently Android apps utilizing location based services are widely used. Understanding the operation of the GPS location provider, among various location providers supported in the Android platform, is an essential task for developers using the Android. This paper, based on the analysis of source codes of the GPS subsystem in the Android platform, shows clearly and orderly the operation of the GPS location provider, in key threads' perspectives as well as in a stepwise fashion from the initialization up to the final location report steps.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.243-249
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• 2013

In this paper, GPS(Global Positioning System) that can be used outdoors and GPS(Global Positioning System) is not available for indoor Wi-Fi(Wireless Fidelity) using the Android-based location information system has been designed and implemented. Pedestrians in a room in order to estimate the location of the pedestrian's position, regardless of need to obtain the absolute position and relative position, depending on the movement of pedestrians in a row it is necessary to estimate. In order to estimate the initial position of the pedestrian Wi-Fi Fingerprinting was used. Most existing Wi-Fi Fingerprinting position error small WKNN(Weighted K Nearest Neighbor) algorithm shortcoming EWKNN (Enhanced Weighted K Nearest Neighbor) using the algorithm raised the accuracy of the position. And in order to estimate the relative position of the pedestrian, the smart phone is mounted on the IMUInertial Measurement Unit) because the use did not require additional equipment.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.119-120
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• 2017

최신 스마트폰은 GPS(Global Positioning System) 신호를 이용하여 비교적 정확한 위치정보를 제공한다. 그래서 GPS를 이용한 다양한 실외용 위치기반서비스 앱이 개발되고 있다. 그러나 GPS를 이용하면 비교적 많은 건전지 에너지가 소모되어 사용자에게 큰 불편을 준다. 본 논문은 지도정보와 에너지 소모가 적은 센서를 이용하여 건전지를 절약하는 방안을 제안한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.507-508
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• 2010

본 논문에서는 구글 (Google)의 개방형 플랫폼인 안드로이드 (Android)를 통해 테마파크의 서비스 품질을 향상 시킬 수 있는 애플리케이션을 개발하고자 한다. 이를 위해 OpenAPI (Open Application Program Interface) 중 가장 많이 사용하고 있는 지도 API와 최근 대중화 되고 있는 스마트폰의 GPS를 이용하여 테마파크 내에 있는 객체들의 실시간 정보를 모니터링 할 수 있는 기능을 제공하고자 한다. 이러한 기능을 통해 현재 테마파크 내의 구조물, 편의시설, 놀이기구 및 동행자의 위치와 정보를 확인할 수 있다. 이를 통해 놀이기구 탑승에 소요되는 시간을 최소화하여 고객 만족도를 향상 시킬 수 있으며 노약자, 어린이 실종이 발생한 경우, 신속하게 실종자의 위치를 확인할 수 있어 아동 범죄, 미아 방지 및 노약자 안전을 확보할 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1588-1595
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• 2021

Android-based smartphones receive the global navigation satellite system (GNSS) signals to determine their location and provide the GNSS raw measurement to users. The available GNSS signals on the current Android devices are GPS, GLONASS, Galileo, BeiDou, QZSS. This research has analyzed the performance of multi-GNSS position accuracy based on the pseudorange of the smartphone for maritime users. Smartphones capable of receiving dual-frequency are installed on a ship, and multi-GNSS raw information in maritime environment was measured to present the results of comparing the GNSS pseudorange-based dual-frequency positioning performance for each smarphone. Furthermore, we analyzed whether the results of the positioning performance can meet the HEA requirement of IMO for maritime navigation users. As the results of maritime experiment, it was confirmed that in the case of the smartphones supporting the dual-frequency, the position accuracy within 6 meters (95%) could be obtained, and the HEA position accuracy performance within 10 meters (95%) required by IMO could be achieved.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.65-66
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• 2015

안압지에는 임해전이라는 정자가 있다. 임해전 내부에는 안압지 조감도가 중앙에 놓여 있고, 가장자리를 따라 안압지에서 출토된 유물들이 전시되어 있다. 그래서 안압지 관광 가이드 앱을 구현하려면 임해전 내부에서 사용자 위치를 판정하는 실내 측위 앱이 있어야 한다. 스마트폰 센서를 이용한 실내측위 방법으로 추측항법 방법이 가장 적당하다. 추측항법을 구현하려면 출발점 좌표를 알아야 하는데, 본 연구에서는 사용자가 임해전 내로 진입하는 순간을 포착하여 임해전 입구를 출발지점으로 지정한다.