• Journal of Positioning, Navigation, and Timing
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• 제8권2호
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• pp.87-94
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• 2019

The Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) positioning has been widely used in geodesy, surveying, and navigation fields. RTK can benefit enormously from the integration of multi-GNSS. In this study, we develop a GPS/BeiDou Navigation Satellite System (BDS) RTK integration algorithm for long baselines ranging from 128 km to 335 km in South Korea. The positioning performance with GPS/BDS RTK, GPS-only RTK, and BDS-only RTK is compared in terms of the positioning accuracy. An improvement of positioning accuracy over long baselines can be found with GPS/BDS RTK compared with that of GPS-only RTK and that of BDS-only RTK. The positioning accuracy of GPS/BDS RTK is better than 2 cm in the horizontal direction and better than 5 cm in the vertical direction. A lower Relative Dilution of Precision (RDOP) value with GPS/BDS integration can obtain a better positional precision for long baseline RTK positioning.

• Korean Journal of Geomatics
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• 제2권1호
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• pp.17-24
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• 2002

The Global Positioning System technology has been widely used in positioning and attitude determination. It is well known that the accuracy, availability and reliability of the positioning results are heavily dependent on the number and geometric distribution of tracked GPS satellites. Because of this limitation, in some situations, such as in urban canyons, underground or inside of buildings, it is difficult to navigate with GPS receiver. Therefore, in order to improve the performance of satellite-based positioning, the integration of GPS with the pseudolite technology has been proposed. With this pseudolite technology, it is expected that seamless positioning service can be provided in a wider area without replacing existing GPS receivers. On the other hand, to adopt pseudolites on a larger scale, it is necessary to verify how the pseudolites may complement the existing GPS-based positioning. In this paper the authors present the details of the experiments and the results of the fundamental verification for seamless positioning using integration of GPS and pseudolite. This paper shows that the accuracy and efficiency of integrating GPS and pseudolite through the dynamic and static positioning experiment. The influence of pseudolite signal on GPS receiver is also discussed. The experimental results indicate that the accuracy of the height component can indeed be significantly improved, to approximately the same level as the horizontal component.

• 한국군사과학기술학회지
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• 제4권2호
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• pp.52-59
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• 2001

In this paper, we have proposed a capability of applying Global Positioning System(GPS) to cannon laying. High precision GPS positioning can be used for measuring precise positions and angles. Therefore, we have tested on applying GPS positioning technique to measurement of positions and angles, which related to cannon laying. First of all, we have determined a GPS reference position using various positioning methods. Then we have carried out several tests that are process of taking corner angles between neighboring two vectors. Each vector can be calculated by post/real time positioning of two GPS antennas placed on the both ends of the howitzer. The Comer Angles from Post processing(CAP) are compared with the other Corner Angles from Real time positioning(CAR). As the results, we have an agreement between CAP and CAR within 0.25 mil average, 0.29 mil standard deviation. Finally, we have discussed about the capabilities and problems in artillery arrangement using GPS.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2002년도 창립 20주년기념 국제학술대회
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• pp.77-84
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• 2002

The Global Positioning System, GPS technology has been widely used in positioning and attitude determination. It is well known that the accuracy, availability and reliability of the positioning results are heavily dependent on the number and geometric distribution of tracked GPS satellites. Because of this limitation, in some situations, such as in urban canyons, underground space or inside of buildings, it is really hard to navigate with GPS receiver. Therefore, in order to improve the performance of satellite-based positioning, the integration of GPS with the pseudolite technology has been proposed. With this pseudolite technology, it is expected that seamless positioning service can be provided in wider area without replacing existing GPS receivers. On the other hand, to adopt pseudolites at larger scale, it is necessary to verify how the pseudolites can complement the existing GPS-based positioning. In this paper the authors present the detail of experimental investigations and the results of the fundamental verification for seamless positioning using integration of GPS and pseudolite. This paper shows that the accuracy and efficiency of integrating GPS and pseudolite through the dynamic and static positioning experiment and discuss about the influence on GPS receiver by pseudolite signal. The experimental results indicate that the accuracy of the height component can indeed be significantly improved, to approximately the same level as the horizontal component.

• Journal of Positioning, Navigation, and Timing
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• 제2권2호
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• pp.131-137
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• 2013

In this study, positioning results that combined the code observation information of GPS and GLONASS navigation satellites were analyzed. Especially, the distribution of GLONASS satellites observed in Korea and the combined GPS/GLONASS positioning results were presented. The GNSS data received at two reference stations (GRAS in Europe and KOHG in Goheung, Korea) during a day were processed, and the mean value and root mean square (RMS) value of the position error were calculated. The analysis results indicated that the combined GPS/GLONASS positioning did not show significantly improved performance compared to the GPS-only positioning. This could be due to the inter-system hardware bias for GPS/GLONASS receivers, the selection of transformation parameters between reference coordinate systems, the selection of a confidence level for error analysis, or the number of visible satellites at a specific time.

• Journal of Positioning, Navigation, and Timing
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• 제3권1호
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• pp.31-36
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• 2014

Precise Point Positioning (PPP) is a stand-alone precise positioning approach. As the quality of satellite orbit and clock products from analysis centers has been improved, PPP can provide more precise positioning accuracy and reliability. A combined use of Global Positioning System (GPS) and Global Orbiting Navigation Satellite System (GLONASS) in PPP is now available. In this paper, we explained about an approach for combined GPS and GLONASS PPP measurement processing, and validated the performance through the comparison with GPS-only PPP results. We also used the measurement obtained from the GRAS reference station for the performance validation. As a result, we found that the combined GPS/GLONASS PPP can yield a more precise positioning than the GPS-only PPP.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.564-567
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• 2007

GPS(Global Positioning System) data has a high accuracy at outdoor positioning generally, but its accuracy decreases in the urban areas with dense buildings. Moreover insufficient number of satelllites prevent us GPS positioning at inside of buildings. To complement these shortcomings of GPS, RFID(Radio Frequency IDentification) has been studied on indoor positioning parts. In Ubiquitous environment, LBS(Location Based Service) which can be used anytime and anywhere is an essential component. We use kalman filter to estimate the real location in GPS and RFID handover area. This study's purpose is to make a continuous positioning system using interlocking RFID and GPS.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.387-395
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• 2020

Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.

• 한국측량학회지
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• 제26권5호
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• pp.529-536
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• 2008

상대측위는 좌표가 정확히 알려진 측점을 기준으로 다른 측점의 좌표를 상대적으로 결정하는 방법으로 측지분야 및 정밀측위 분야에 활용되고 있다. DGPS(Differential GPS) 기법은 일정한 거리 내에서 위성과 수신기의 공통오차를 소거할 수 있다는 장점이 있지만 기선의 길이가 증가할수록 오차가 증가하는 단점을 가지고 있다. GPS 절대측위는 상대측위와는 달리, 원하는 측점의 수신기에서 수신한 GPS 위성들의 신호를 이용하여 독립적으로 측점의 위치를 결정하는 방식이다.이때 관측된GPS 신호에는 위성시계 오차, 전리층 및 대류권 통과에 따른 오차, 다중경로 오차 등 위치 결정에 영향을 주는 여러 오차 요인들이 포함되어 있어 이를 보정해 주어야 한다. 본 연구에서는 Bernese GPS Software 5.0을 이용한 정밀절대측위 방법과 AUSPOS - Online GPS Processing Service를 이용한 상대측위 방법으로 국토지리정보원의 GPS 상시관측소 관측자료를 처리하고 이를 국토지리정보원의 고시성과와 비교.분석하여 정밀절대측위를 이용한 정밀위치결정의 정확도를 분석하고 그 효용성을 제시 하고자 한다.

• 한국측량학회지
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• 제32권6호
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• pp.599-606
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• 2014

Since the accuracy of Global Positioning System (GPS)-based vehicle positioning system is significantly degraded or does not work appropriately in the urban canyon, the integration techniques of GPS with Inertial Navigation System (INS) have intensively been developed to improve the continuity and reliability of positioning. However, its accuracy is degraded as INS errors are not properly corrected due to the GPS signal blockage. Recently, the image-based positioning techniques have been started to apply for the vehicle positioning for the advanced in processing techniques as well as the increased the number of cars installing the camera. In this study, Single Photo Resection (SPR), which calculates the camera exterior orientation parameters using the Ground Control Points (GCPs,) has been integrated with the INS/GPS for continuous and stable positioning. The INS/GPS/SPR integration was implemented in both of a loosely and a tightly coupled modes, based on the Extended Kalman Filter (EKF). In order to analyze the performance of INS/SPR integration during the GPS outage, the simulation tests were conducted with a consideration of factors affecting SPR performance. The results demonstrate that the accuracy of INS/SPR integration is depended on magnitudes of the GCP errors and SPR processing intervals. Additionally, the simulation results suggest some required conditions to achieve accurate and continuous positioning, used the INS/SPR integration.