• Journal of the Korea Safety Management & Science
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• v.9 no.5
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• pp.97-101
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• 2007

As the use of vehicle route application and LBS(location based service) are fast grew, the importance of maintaining road network data is also increased. To maintain road data accuracy, we can collect road data by driving real roads with probe vehicle, or using digital image processing for the extraction of roads from aerial imagery. After compare the new road data to current database, we can update the road database, but that job is mostly time and money consuming or can be inaccurate. In this paper, an updating method of using GPS(global positioning system) enabled cell phone is proposed. By using GPS phone, we can update road database easily and sufficiently accurately.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.4
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• pp.379-385
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• 2000

In order to evaluate the stability of permanent GPS arrays for obtaining high precision coordinates, spectral analysis uses the least square spectrum analysis to the coordinate variations of Suwon, Tsukuba and Sanghai stations. Permanent GPS observations at Suwon, Tsukuba and Sanghai have been more or less continuously carried out since 1994. Time series of the resulting coordinate variations are analyzed for long term repeatability and periodic behaviour.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.106-111
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• 2004

A data communication should be carried out by a SSB(Single Side Band) to collect real time position data of fishery ship automatically, and a study on the protocol for exchanging the information with GPS should be made. A research about regional and concentrated maritime information should be first made to obtain ship's voyage data and also, research of the Modem and transmitter-receiver controller for sending voice and data simultaneously through a SSB and of the acquisition of data through a GPS also should be carried out.

• Journal of Communications and Networks
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• v.4 no.3
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• pp.209-220
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• 2002

In this paper, we propose a hierarchical packet scheduling technique to closely approximate a hierarchical extension of the generalized processor sharing model, Hierarchical Generalized Processor Sharing (H-GPS). Our approach is to undertake the tasks of service guarantee and hierarchical link sharing in an independent manner so that each task best serves its own objective. The H-GPS model is decomposed into two separate service components: the guaranteed service component to consistently provide performance guarantees over the entire system, and the excess service component to fairly distribute spare bandwidth according to the hierarchical scheduling rule. For tight and harmonized integration of the two service components into a single packet scheduling algorithm, we introduce two novel concepts of distributed virtual time and service credit, and develop a packet version of H-GPS called Hierarchical Fair Queueing (HFQ). We demonstrate the layerindependent performance of the HFQ algorithm through simulation results.

• Smart Structures and Systems
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• v.7 no.5
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• pp.349-363
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• 2011

To assess the performance of a structure requires the measurement of global and relative displacements at critical points across the structure. They should be obtained in real time and in all weather condition. A Global Navigation Satellite System (GNSS) could satisfy the last two requirements. The American Global Position System (GPS) provides long term acquisitions with sampling rates sufficient to track the displacement of long period structures. The accuracy is of the order of sub-centimetres. The steel building which hosts the authors' laboratory is the reference case-study within this paper. First a comparison of data collected by GPS sensor units with data recorded by tri-axial accelerometers is carried out when dynamic vibrations are induced in the structure by movements of the internal bridge-crane. The elaborations from the GPS position readings are then compared with the results obtained by a Finite Element (FE) numerical simulation. The purposes are: i) to realize a refinement of the structural parameters which characterize the building and ii) to outline a suitable way for processing GPS data toward structural monitoring.

• Journal of Drive and Control
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• v.17 no.4
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• pp.8-14
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• 2020

Intelligent devices using ICT technology have been introduced in the field of construction machinery to improve productivity and stability. Among the intelligent devices, Machine Guidance is a device that provides real-time posture, location, and work range to drivers by installing various sensors, controllers, and satellite navigation systems on construction machines. Conversely, the efficiency of equipment that requires location information, such as machine guidance, will be greatly reduced in buildings, and tunnels in the GPS blind spots. Thus, the other high-precision positioning technologies are required in the GPS blind spot zone. In this study, we will develop a relative position measurement system that provides precise location information such as construction machinery and robots in a local area where the GPS reception is difficult. A relative position measurement system tracks a marker in the form of a sphere installed on a vehicle by using the image base tracking technology, and measures the distance and direction information to the marker to calculate a position.

• Spatial Information Research
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• v.13 no.1 s.32
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• pp.19-29
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• 2005

In this study, Real Time Kinematic GPS(RTK GPS) was conducted twice at the same site in two different seasons, respectively to check the possibility of it as the mapping tool, and how the factor affecting the accuracy of it. As a result, most parts of a small garden except f3r the worst environments surrounded with lots of tree canopy and several buildings were mapped using RTK GPS even in spring, full of a green foliage and winter as well. However, the mapping accuracy and the availability of RTK GPS were not so high. The study showed that it is recommended in RTK GPS mapping to utilize Total Station, etc. in the worst urban environments unable to track the satellite signals with ease.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.243-250
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• 2017

GPS(Global Positioning System) signal structure uses spread spectrum and the received power is relatively lower than the receiver noise figure. Therefore, it is vulnerable to the RF interferences and it could restrict on the safety navigation. The objective of this paper is to research on the spectral domain GPS interference rejection algorithm using proposed K-median filtering threshold setting method. In the performance test, the proposed algorithm has a relatively higher ISR(interference to signal ratio) compared with the conventional temporal domain technique in case of time variant interference signals.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.739-744
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• 2005

For the structure of AVLS is required to the GPS-MDT for realtime acquisition the position reporting of vehicle and traffic management S/W. It is necessary that the MODEM using VHF transceiver base on GPS and monitoring program for display base on GIS the traffic status by vehicles position report in management system. The other wise, vehicles among management system that is required the automatic communications protocol for GPS information and mobile's ID. In his paper have studied the VHF modem for transmission the voice and data at same time and S/W for management system using GIS-tool.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8C
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• pp.745-757
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• 2007

In this paper, we propose a design of GPS anti-jamming system and its operational method, which can effectively suppress interference and jamming signals induced in GPS receiver. The 7-array antenna used in the proposed system is composed of conventional 6 equi-spaced circular elements with one element on the center of antenna and can be efficiently operated under power-constrained conditions. Futhermore, in this paper, we analyze the structure and complexity of STAP and SFAP which are well known techniques in adaptive array antenna signal processing, and we compare the BER performances between STAP and SFAP in various jamming environment based on the same complexity.