- Volume 10 Issue 1
In this parer, we propose a new way of improving DGNSS service using combination of multiple SBAS information. Because SBAS uses Geostationary Earth Orbit (GEO) satellites, it has very large coverage but it can be unavailable in urban canyon because of visibility problem. R. Chen solved this problem by creating Virtual Reference Stations (VRS) using the SBAS signal . VRS converts SBAS signal to RTCM signals corresponding its location, and broadcast the converted RTCM signals over the wireless internet. This method can solve the visibility problem cost effectively. Furthermore it can solve DGNSS coverage problem by creating just a transmitter instead of a reference station. Developing above method, this paper proposes the methods that integrate two or more SEAS signals into one RTCM signal and broadcast it. In Korea, MSAS signal is available even though it is not officially certified for Korean users. As a Korean own SBAS-like system, there is the internet-based KWTB (Korean WADGPS Test Bed) which we developed and released at ION GNSS 2006. As a result, virtually two different SBAS corrections are available in Korea. In this paper, we propose the integration methods for these two independent SBAS corrections and present the test results using the actual measurements from the two systems. We present the detailed algorithm for these two methods and analyze the features and performances of them. To verify the proposed methods, we conduct the experiment using the logged SBAS corrections from the two systems and the RINEX data logged at Dokdo monitoring station in Korea. The preliminary test results showed the improved performance compared to the results from two independent systems, which shows the potential of our proposed methods. In the future, the newly developed SBASs will be available and the places which can access the multiple SBAS signals will increase. At that time, the integration or combination methods of two or more SBASs will become more important. Our proposed methods can be one of the useful solutions for that. As an additional research, we need to extend this research to the system level integration such as the concept of the decentralized W ADGPS.
SBAS Integration;Interoperability;Multiple Correction Combination
- R. Chen and X. Li, Virtual differential GPS based on SBAS signal, Journal of GPS Solutions, Vol.8,No.4, 2004. https://doi.org/10.1007/s10291-004-0114-6
- Association of Internationle de Signalisation Maritime, IALA Recommendation R-135 On The Future of DGNSS, Edition 1, IALA, 2006.
- D. Kim and C. Kee, Solution for the Interoperability of Asian WADGPS Systems : Decentralized WADGPS, Proceedings of International symposium on GPS/GNSS, Tokyo, Japan, 2003.
- RTCA Special Committee 159 Working Group 2, Minimum Operational Performance Standards for Global Positioning System / Wide Area Augmentation System Airborne Equipment, RTCA Document Number DO-229C, 2001
- RTCM Special Committee No. 104, Amendment2 to RTCM Standard 10403. 1, Differential GNSS Services –Version 3, 2007.
- S. Skone and A. Coster, Performance Evaluation of DGPS versus SBAS / WAD GPS for Marine User, Proceedings of the ION GNSS 20th International Technical Meeting,pp. 1904-1913, 2007.
- C. Kee, D. Kim, C. Pyong, Suggestions of a Substantial Alternative to Implement Asian WAD GPS Network: Decentralized WADGPS, The 7th GNSS Workshop-International Symposiumon GPS/GNSS, Seoul, Korea, December, 2000, pp. 121-125.
- D. Kim, Y. Yun, B. Park, S. Jeon, Y. Sohn, and C. Kee, Development and Preliminary Test Results of Korean WADGPS Test Bed Using NDGPS Infrastructure in Korea, Proceedings of ION GNSS2006, ForthWorth, Texas, 2006.