• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.278-280
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• 2004

GPS Navigation Solutions are used for operational orbit determination for the KOMPSAT-1 spacecraft. GPS point position data are definitely affected by systematic errors as well as noise. Indeed, the systematic error effects tend to be longer term since the GPS spacecrafts have periods of 12 hours. And then, the overlap method of determining orbit accuracy is always optimistic because of the presence of systematic errors with longer term effects. In this paper, we investigated the measurement noise and the system error for the KOMPSAT-l GPS Navigation Solutions. To assess orbit accuracy with this type of data, we use longer data arcs such as 5-7 days instead of 30 hour data arc. For this assessment, we should require much more attention to drag and solar radiation drag parameters or even general acceleration parameters in order to assess orbit accuracy with longer data arcs. Thus, the effects of the consideration of the drag, solar radiation drag, and general acceleration parameters were also investigated.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.08a
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• pp.183-206
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• 2000

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.4
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• pp.373-382
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• 2016

In this study, an EKF (Extended Kalman Filter) based database reference navigation using both gravity gradient and terrain data was performed to complement the weakness of using only one type of geophysical DB (Database). Furthermore, a new algorithm which combines the EKF and profile matching was developed to improve the stability and accuracy of the positioning. On the basis of simulations, it was found that the overall navigation performance was improved by the combination of geophysical DBs except the two trajectories in which the divergence of TRN (Terrain Referenced Navigation) occurred. To solve the divergence problem, the profile matching algorithm using the terrain data is combined with the EKF. The results show that all trajectories generate the stable performance with positioning error ranges between 14m to 23m although not all trajectories positioning accuracy is improved. The average positioning error from the combined algorithm for all nine trajectories is about 18 m. For further study, a development of a switching geophysical DB or algorithm between the EKF and the profile matching to improve the navigation performance is suggested.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.1
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• pp.114-122
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• 2009

An adaptive Kalman filter is designed as a post-navigation filter to improve the accuracy of GPS receiver's navigation performance in high dynamic environments. Not only the adaptive Kalman filter reduces the large noise error of navigation data which is obtained by least square method, but also the filter is not degraded as normal Kalman filter in high acceleration movements because the system noise is estimated. Also an initialization structure of the filter is desisted in consideration for irregular output condition of navigation data by least squared method such as reacquisition status in GPS receiver. The filter performance is verified by GPS simulator which has the simulation capability of high velocity and acceleration. Finally, a vehicle test including DGPS is executed to conform the real improvement of that filter performance. This filter can be applied to various data measurement systems to improve accuracy in high dynamic conditions besides GPS receiver.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.699-701
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• 2010

For the development of surveillance Multi Sensor and IFOG, development of integrated surveillance camera for day and night time of its system Control Unit design and navigation device interlocking system was made. Control Unit analysis of integrated ship system began with selection of control unit related to feasible navigation device list.After sorting navigation equipment list, applications, features, connection methods, communication methods, data type of control unit and data direction between navigation equipments and the data types of each navigation equipment is sorted to observe its performance.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.271-278
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• 2013

In this paper, ECEF to ECI coordinate transformation algorithm which uses EOP parameters in GPS civil navigation message is introduced, and ECEF to ECI coordinate transformation simulation results were analyzed. The ECEF to ECI coordinate transformation includes GPS to UTC, and UTC to other types of time conversions and EOP data processing algorithms. The ECEF to ECI coordinate conversion algorithm was certified using real LEO satellite position, velocity GPS data, and EOP data which offered by the Earth Orientation Center.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.4
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• pp.39-44
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• 2012

This paper propose a transmission method for "Transportation system" that can decide precise position under wide area road traffic environment. For precise position detecting, central station collect multiple receiver station's satellite navigation data and generate correction information. In this process, we need efficient real time transmission method for satellite navigation message that has variable data size. We propose real time data transmission method. This real time transmission method offer efficient processing structure for multiple receiver station's satellite navigation message. This paper explains proposed real time transmission method and proofs this transmission method.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.257-269
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• 2023

This paper presents a method for detecting faults in data obtained from the Automatic Identification System (AIS) of surface vessels. The data include latitude, longitude, Speed Over Ground (SOG), and Course Over Ground (COG). We derive two methods that utilize two models: a constant state model and a derivative augmented model. The constant state model incorporates noise variables to account for state changes, while the derivative augmented model employs explicit variables such as first or second derivatives, to model dynamic changes in state. Generally, the derivative augmented model detects faults more promptly than the constant state model, although it is vulnerable to potentially overlooking faults. The effectiveness of this method is validated using AIS data collected at a harbor. The results demonstrate that the proposed approach can automatically detect faults in AIS data, thus offering partial assistance for enhancing navigation safety.

• Journal of Navigation and Port Research
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• v.36 no.1
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• pp.1-7
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• 2012

A concept of the "e-Navigation" was introduced in 2005 and implementation strategies are under way by IMO/IALA in the maritime safety area. Specially VTS is an important maritime traffic monitoring and aids to navigation system which is aims to improve safety, navigation efficiency and protect the marine environment. The demand of the inter-VTS networking has been increased and standardization is underway for realization of shore side collaboration for maritime safety in IALA. But there may be security problems in the inter-VTS networks if they have not proper security mechanism. The hacking of realtime ship position and sensitive maritime surveillance information caused a critical accident of vessel, human life and environment by terrorist. This paper aims to design of a secure inter-VTS network structure and related security protocol for secure sharing of sensitive maritime data.