• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.1
• /
• pp.79-87
• /
• 1999

For its simplicity and cost effectiveness in implementation, the Inverted DGPS is well suited for some specific applications like automatic vehicle location systems, where the monitoring station needs accurate position of the vehicles in the street. In the Inverted DGPS, the user sends its GPS position and associated satellite informations to the reference station, and the corrections are made at the reference station to get differentially corrected user position. A fundamental requirement in IDGPS is that the user and the reference station must use the same satellites when the corrections are made. But in practice, it is not often satisfied. Inverted DGPS is also suffered from performance degradation as the baseline become large like DGPS. IDGPS system using multi-reference station can resolve this problem. In this paper a simple multi-reference IDGPS algorithm is proposed and some experiments and analysis are peformed. Experiment results show that IDGPS can achieve the positioning performance as accurate as the DGPS can provide.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.22 no.1
• /
• pp.37-44
• /
• 2004

This study aims to develop an optimized system for container management in Customs Free Zone. Positioning methods and wireless data communication methods were analyzed and then introduced to the container management system constructed in this study. For the trial test, it was founded that the accuracy of the GPS receiver using a single frequency band was not satisfied. However, the position of container can be matched with a digital map by map matching process. It was also founded that the precise method like Inverted DGPS is required when sight of a satellite is blocked.

• Journal of Astronomy and Space Sciences
• /
• v.18 no.1
• /
• pp.63-70
• /
• 2001

IDGPS(Inverted Differential Global Positioning System) is one of technique improving the accuracy of GPS positioning and is mostly used for tracking an automatic vehicle. In the IDGPS, the user send it’s GPS position and related satellite information to dispatcher, and the corrections are made at the dispatcher to get corrected user position. IDGPS suffered correction degradation as the baseline become large. This problem is resolved using NIDGPS(Network IDGPS). As the experimental results are demonstrated, the improvement of position accuracy using IDGPS and NIDGPS is verified.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2222-2224
• /
• 2001

This paper presents the implementation of an efficient car tracking system based on Inverted DGPS (IDGPS) using mobile phone and internet for data communication link. The IDGPS technique, which may provide the same level of accuracy as DGPS, is subject to degradation in real time applications when transmission time delays occur in the communication links. Therefore, an effective communication system is the key element for successful application of the IDGPS. The combination of internet and mobile phones provides a high data rate, unlimited communication packet size, flexible data structure, and wide coverage without additional communication devices. An implementation of such a data link system is described. Field test results are included to evaluate the performance of the proposed system.

• Journal of Korean Society of Transportation
• /
• v.17 no.3
• /
• pp.7-20
• /
• 1999

This Paper Presents a Internet-based Real-Time Automated Vehicle Location System(AVLS), which is able to Provide users with real-time vehicle Positioning information. When Inverted Differential GPS is available, this system does more aggressive position correction than GPS, and more useful for public transportation and commercial application than DGPS in terms of cost.