• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3534-3553
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• 2021

The low cost of Bluetooth technology has led to its wide usage in indoor positioning. However, some inherent shortcomings of Bluetooth technology have limited its further development in indoor positioning, such as the unstable positioning state caused by the fluctuation of Received Signal Strength Indicator (RSSI) and the low transmission frequency accompanied by a poor real-time performance in positioning and tracking moving targets. To address these problems, an indoor fusion positioning algorithm of Bluetooth technology and pedestrian dead reckoning (PDR) based on a particle filter with dynamic adjustment of weights calculation strategy (BPDW) will be proposed. First, an orderly statistical filter (OSF) sorts the RSSI values of a period and then eliminates outliers to obtain relatively stable RSSI values. Next, the Group-based Trilateration algorithm (GTP) enhances positioning accuracy. Finally, the particle filter algorithm with dynamic adjustment of weight calculation strategy fuses the results of Bluetooth positing and PDR to improve the performance of positioning moving targets. To evaluate the performance of BPDW, we compared BPDW with other representative indoor positioning algorithms, including fingerprint positioning, trilateral positioning (TP), multilateral positioning (MP), Kalman filter, and strong tracking filter. The results showed that BPDW has the best positioning performance on static and moving targets in simulation and actual scenes.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.3
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• pp.117-122
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• 2014

In CDGPS, ambiguity resolution is determined by the performance of a floating solution, and thus, the performance needs to be improved. In the case of precise positioning at a stationary position, the batch method using multiple measurements is used for the accuracy improvement of a position. The position accuracy performance of a floating solution is outstanding, but it has a problem of high computation cost because all measurements are used. In this study, to improve the floating solution performance of the initial static user in CDGPS, a floating solution method using a recursive filter was implemented. A recursive filter estimates the position solution of the current epoch using the position solution of up to the previous epoch and the pseudorange measurement of the current epoch. The computation cost of the floating solution method using a recursive filter was found to be similar to that of the epoch-by-epoch method. Also, based on actual GPS signals, the floating solution performance was found to be similar to that of the batch method. The floating solution using a recursive filter could significantly improve the performance of the prompt initial position and ambiguity resolution of the initial static user.

• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.53-65
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• 2022

According to the advancement of the GNSS satellite positioning system, the module of hardware and operation software reflecting accuracy and economical efficiency is implemented in the user sector including the multi-channel GNSS receiver, the multi-frequency external antenna and the mobile app (App) base public positioning analysis software etc., and the multichannel GNSS RTK positioning of the active configuration method (DIY, Do it yourself) is possible according to the purpose of user. Especially, as the infrastructure of multi-GNSS satellite is expanded and the potential of expansion of utilization according to various modules is highlighted, interest in the utilization of multi-channel low-cost GNSS receiver module is gradually increasing. The purpose of this study is to review the multi-channel low-cost GNSS receivers that are appearing in the mass market in various forms and to analyze the utilization plan of the "address information facility investigation project" of the Ministry of Public Administration and Security by constructing the multi-channel low-cost GNSS positioning module based RTK survey system (hereinafter referred to as "multi-channel GNSS RTK module positioning system"). For this purpose, we constructed a low-cost "multi-channel GNSS RTK module positioning system" by combining related modules such as U-blox's F9P chipset, antenna, Ntrip transmission of GNSS observation data and RTK positioning analysis app through smartphone. Kinematic positioning was performed for circular trajectories, and static positioning was performed for address information facilities. The results of comparative analysis with the Static positioning performance of the geodetic receivers were obtained with 5 fixed points in the experimental site, and the good static surveying performance was obtained with the standard deviation of average ±1.2cm. In addition, the results of the test point for the outline of the circular structure in the orthogonal image composed of the drone image analysis and the Kinematic positioning trajectory of the low cost RTK GNSS receiver showed that the trajectory was very close to the standard deviation of average ±2.5cm. Especially, as a result of applying it to address information facilities, it was possible to verify the utility of spatial information construction at low cost compared to expensive commercial geodetic receivers, so it is expected that various utilization of "multi-channel GNSS RTK module positioning system"

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.169-171
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• 2010

The goal of this study is to evaluate the performance of different solution types(a GPS-only, a GLONASS-only, and a GNSS solution) on GNSS positioning modes which are point positioning and relative positioning(DGNSS-, Static-, and Kinematic-solutions). I started with GNSS sites of seoul metropolitan government's RTK network which providing combined GPS/GLONASS observations : Gangseo(GANS), Dobong(DBON). The positioning accuracy of different solution types on positining modes are compared. Considering the compared results of all cases, can find not only the difference of the performance between the GNSS solution and the GPS-only solution is very small, but also the GLONASS-only solution is not far from the other solution types taking into consideration that GLONASS system is not (yet) a complete system.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.544-550
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• 2008

In this paper, an efficient positioning algorithm is proposed for a local positioning system using ultrasound and RF in WSN. The proposed positioning algorithm is the modified Savarese method where measurement noise characteristics are included as a weighting. Furthermore the ill-conditioned and the singularity problem occurred when all beacons are installed at the same height are removed. And the method is applicable to 2D positioning with 2 beacons only. The experiments with implemented system show the accurate seamless positioning less than 2cm error both static and dynamic experiments while the original Savarese method can not provide positions.

• Journal of Environmental Science International
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• v.11 no.2
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• pp.103-110
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• 2002

The position fixing usually is determined by triangulation, traverse surveying and astronomy surveying. However, when the station is moving, it is impossible to determine its position continuously by the former method. By a satellite positioning method(GPS), this problem can be solved. In our study, we used two methods to determine the length and coordinate of a point position. One is a kinematic GPS method and the other is a static one. Each is based on carrier phase measurement and employs a relative position technique. We implemented observation experiments such as Geodimeter and DGPS(Differential GPS) successfully. To estimate the accuracy between the kinematic and static methods, we compared the results of Geodimeter, the kinematic, and the static. The results showed that the static is relatively a little more accurate than the kinematic. However, in the kinematic mode, when we received the GPS data for a long time, we found that the kinematic also had a high accuracy value for the length survey Finally, we applied the GPS to Jeju Harbor Breakwater to examine the applicability of GPS for coastal ocean structure based on the kinematics and the statics, respectively.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.36-43
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• 2009

In this study, the impact of the covariance between the baselines on the network-based GPS positioning is analyzed. For the analysis, the multi-baseline solutions with properly modeled covariance between the baselines and the combined solutions from the single-baseline solutions are obtained, respectively. Then, the accuracies of both solutions are evaluated in terms of coordinate residuals, i.e., the differences between the positioning solutions and the published stations' coordinates. The results indicate that the positioning accuracy in static mode depends much on the geometry of GPS satellites rather than the proper modeling of covariance between the baselines. Also, slight but negligible improvement in positioning accuracy is observed in static solutions. Therefore, one may use combined solutions as an alternative to multi-baseline solutions for the network-based GPS positioning. However, multi-baseline solution with properly modeled covariance between the baselines is recommended to use especially for the applications to detect very small displacement, i.e., deformation of the building or bridge.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.1 s.19
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• pp.51-57
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• 2002

GPS proved to very practical in the application of geodesy and surveying such Civil Engineering, control point surveying and the deformation surveying o( structure, but the accuracy of static GPS positioning is degraded at the sites which the visible satellites of GPS are less than 4, i.e. the urban area covered with the high building and the industrial zone. Thus, the combined GPS/GLONASS system was introduced to acquire the high accuracy of static positioning by a few satellites. So the combined GPS/GLONASS system show the good results at the sites which the accuracy of positioning is degraded due to few satellites, the cutoff of signal, and multipath in the urban area.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.671-679
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• 2011

Now, for the continuous location detection of train, The method which the moving distance and speed of vehicles are detected using an odometer mounted within railway vehicle, is used in railway domain generally. There are some problems that the train's positioning errors are accumulated as the moving distances increase. To solve this problems, The Train-borne Positioning System is being developed at Korea Railroad Research Institute. It is required to evaluate exactly a positioning performance of The Train-borne Positioning System for improvement of performance. Therefore, in this paper, we review the CDGPS methods to acquire reference position for performance evaluation of Train-borne Positioning System and verify the accuracy of the reference position through the static test and the vehicle test.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.386-389
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• 2007

Currently, fast and accurate long baseline positioning in kinematic mode is a challenging topic, but positional accuracy can be improved with the help of the network-derived external ionospheric corrections. To provide not only ionospheric corrections, but also their variances, satellite-by-satellite interpolation for the ionospheric delays is performed using the least-squares collocation (LSC) method. Satellite-by-satellite interpolation has the advantage in that the vertical projection used in single-layer ionospheric model is not required. Also, more reliable user positioning and the corresponding accuracy assessment can be obtained by providing not only external ionospheric corrections but also their variances. The rover positioning with and without the external ionospheric delays in both rapid-static and kinematic mode was performed and analyzed. The numerical results indicate that the improvement in the positioning quality is achieved using the proposed method. With the TAMDEF network in Antarctica, 18 % improvement in mean time-to-fix in kinematic mode was achieved.