• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.11
• /
• pp.2261-2270
• /
• 2015

GIS(Geographic Information System) based Positioning technique uses geographic information to predict which satellites are visible or invisible. GPS positioning has poor positioning accuracy in dense urban area where tall buildings block the satellite signals. In this paper, we proposed GIS based Advanced Positioning technique of Mobile GPS to resolve this problem. Particularly, this technique improves positioning accuracy in dense urban area. It is consist of ephemeris and GIS server. We will inversely estimate pseudorange by using NMEA-0183 output data of mobile GPS. After that, we can find more accurate position by using ephemeris and GIS information.

• Proceedings of the Safety Management and Science Conference
• /
• 2010.11a
• /
• pp.331-335
• /
• 2010

본 논문에서는 위치기반서비스의 핵심기능을 담당하는 측위기술 중 주변의 다양한 잡음환경에서도 다른 측위기술에 비해 비교적 측위오차를 줄일 수 있는 Fingerprint 기법을 적용하여 객체의 위치를 결정하는 방법을 제시하였다. 특히, Fingerprint 기법을 활용함에 있어서 결정적 측위방법이 아닌 확률적 측위방법을 사용하였고, 기존의 연구들에서 제시된 확률적 측위방법에서 인접 RP(Reference Point)들과의 영향성까지 고려한 측위방법을 제시한 것이 본 연구의 특징이다. 비주얼베이직 6.0으로 측위 프로그램을 구현하였고, 실내 외 연속측위의 선행연구로서 실내 측위 테스트를 통해 기존의 결정적 방법, 확률적 방법, 그리고 본 연구에서 제안하는 방법의 측위 정확성을 평가하였다. 테스트 결과, 결정적 측위 방법 및 기존의 확률적 측위방법과 비교하여 각각 평균 15%와 7% 측위 오차가 감소하였다.

• The KIPS Transactions:PartC
• /
• v.16C no.5
• /
• pp.645-652
• /
• 2009

Location-based service providing the customized information or service according to the user's location has attracted a lot of attention from the mobile communication industry. The service is realized by means of several building blocks, a localization scheme, service platform, application and service. The localization scheme figures out a moving target's position through measuring and processing a wireless signal. In this paper, we propose an adaptive localization scheme in an indoor localization system based on IEEE 802.15.4 standard. In order to enhance the localization accuracy, the proposed scheme selects the best reference points and adaptively reflects the changes of propagation environments of a moving target to approximate distances between the target and the reference points in RSS(Received Signal Strength) based localization system using triangulation. Through the implementation of the localization system, we verify the performance of the proposed scheme in terms of the localization accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.2A
• /
• pp.124-129
• /
• 2002

We propose a wireless positioning system using IC-IPDL method that exploits the modified-IPDL method and the interference cancellation techniques to improve hearability. In the proposed system, IPDL method is modified to maintain the transmission of CPICH for stability of CDMA network Simultaneously in mobile CPICH is cancelled out using the interference cancellation techniques for improving hearability. The simulation results showed that the proposed location system has a compatible performance to the standard IPDL method though CPICH exists during idle period.

• Journal of Navigation and Port Research
• /
• v.30 no.10 s.116
• /
• pp.839-845
• /
• 2006

A laser docking system provides a centimeter-level accuracy distance from jetty mounted laser sensors in order to help a vessel to approach to a pier. It is very accurate & useful, whereas there are too many considerable problems. Laser sensors of the laser docking system need to be correctly positioned and installed on a jetty to allow for full range of vessels to be berthed and to consider loading condition and tidal variations. Above all, the laser docking system is expensive and its service coverage is limited. In order to solve these problems, CDGPS positioning method using GPS satellites has been proposed. This paper presents that, through RHDOP simulation, the previous CDGPS positioning method using only GPS satellites is not able to provide the continuous service with centimeter-level positioning accuracy. And this paper proposes a pseudolite-augmented positioning method for vessel docking in order to solve the problem of the continuous service on the previous CDGPS positioning method. In this paper, pseudolite is used to aid in CDGPS positioning. This paper shows that the proposed method can provides the continuous service through comparison analysis of RHDOP simulation results between the GPS satellite constellation and the pseudolite-augmented GPS satellite constellation. Furthermore, it is shown that the proposed positioning method satisfies the positioning performance required for vessel automatic docking at a test bed designed for performance evaluation.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.6
• /
• pp.1059-1068
• /
• 2021

In urban areas, GPS(Global Positioning System)/GNSS(Global Navigation Satellite System) signals are blocked or distorted by structures such as buildings, which limits positioning. To compensate for this problem, in this paper, fingerprinting-based positioning using RSRP(: Reference Signal Received Power) information of LTE signals is performed. The W-KNN(Weighted - K Nearest Neighbors) technique, which is widely used in the positioning step of fingerprinting, yields different positioning performance results depending on the similarity distance calculation method and weighting method used in correlation. In this paper, the performance of the fingerprinting positioning according to the techniques used in correlation is comparatively analyzed experimentally.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.2
• /
• pp.155-164
• /
• 2013

Two design techniques for more accurate and more convenient hybrid positioning system with visible light communication (VLC) and ad-hoc wireless network infrastructure are proposed, in order to overcome the problems of high estimation error, high cost, and limited service range of the conventional positioning techniques. First method is based on a non-carrier VLC based hybrid positioning technique for applications involving of low data rate optical sensing and narrow-range visible light reception from transmitter, and long-range positioning. The second method uses a 4 MHz carrier VLC-based hybrid positioning technique for a high data rate optical sensing and wide-range visible light receiving from transmitter, and mid-range positioning applications. In indoor environments with obstacles where there are long-range 7731.4cm and mid-range 2368cm distances between an observer and a target respectively, the hybrid positioning developed with two design techniques are tested, and the proposed system is verified and analyzed in this paper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.239-241
• /
• 2011

Recently, studies on the indoor positioning system in application of wireless AP have been actively going on. The indoor wireless positioning system can be classified into several types according to the positioning techniques. Among them, the fingerprint technique is a technique that establishes the radio map by collecting MAC information of AP and RSSI (Received Signal Strength Indication) before executing positioning and then determines the position in comparison with the information of AP collected during the course of positioning. In the traditional fingerprint techniques, they control and manage by installing APs that are utilized for positioning. However, in case of specific indoors, the management can be done by installing a small number of APs but, in case of wide outdoors, it's practically impossible to install and manage equipments for positioning. In order to solve such problem, there is an improved fingerprint technique that utilizes the APs that are already scattered around. This technique will allow positioning without additional cost, but even the improved fingerprint positioning technique may incur dropped accuracy as well due to wide fluctuation of the AP information. In this paper, the traditional fingerprint technique and the improved fingerprint technique are explained in comparison, and we will compares difference in performance with the proposed WPS_WS (Wi-Fi Positioning System_Weak Signal) technique.

• KIPS Transactions on Computer and Communication Systems
• /
• v.5 no.10
• /
• pp.373-378
• /
• 2016

Recently, IPS(Indoor Positioning System) Technology has been progressing study and research, It has been studied in the fingerprinting and trilateration continuously. however because Fingerprinting and Trilateration Technology use AP(Access Point) for Positioning Calculation, Fingerprinting and Trilateration are not never had a credit positioning accuracy by using unstable RSSI in large scale. in this paper, to improve the problem about precise positioning in wide area, we introduced a concept of Sector including Cell. Sectors are not involved in each other and only fingerprinting calculation is proceed in a sector. we suggest this fingerprinting system considering efficiency and accuracy and compared to conventional fingerprinting, we demonstrated our system efficiency by mathematical techniques.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.11C
• /
• pp.1098-1105
• /
• 2009

In this paper, we propose an asynchronous UWB (Ultra Wide Band) Positioning scheme that can provide precise positioning performance with low complexity and low power consumption. We also present the residual test to improve the positioning performance in multipath channels having heavy NLoS (Non-Line of Sight) components. As compared to conventional ToA (Time of Arrival) positioning scheme that requires round-trip transmissions as many as the number of beacons, the proposed UWB positioning scheme effectively decrease power consumption and processing delay since a single round-trip transmission is only required. Also, as compared to conventional TDoA (Time Difference of Arrival) positioning scheme requiring precise synchronization among the beacons, asynchronous nature of the proposed scheme achieves very low system complexity. Through simulations in LoS (Line of Sight) channel models, we observe that the proposed scheme requires low system complexity, low power consumption, while providing positioning performance of almost the same accuracy as the conventional ToA and TDoA positioning schemes. In addition, the proposed scheme by employing the residual test achieves accurate positioning performance even in multipath channels having heavy NLoS components.