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See detailEvaluation of a regional real-time precise positioning system based on GPS/BeiDou observations in Australia
Ding, Wenwu UL; Tan, Bingfeng; Chen, Yongchang et al

in Advances in Space Research (2018)

The performance of real-time (RT) precise positioning can be improved by utilizing observations from multiple Global Navigation Satellite Systems (GNSS) instead of one particular system. Since the end of ... [more ▼]

The performance of real-time (RT) precise positioning can be improved by utilizing observations from multiple Global Navigation Satellite Systems (GNSS) instead of one particular system. Since the end of 2012, BeiDou, independently established by China, began to provide operational services for users in the Asia-Pacific regions. In this study, an regional RT precise positioning system in Australia is developed to evaluate the performance of GPS/BeiDou observations in providing high precision positioning services for users. Fixing three hourly updated satellite orbits, RT correction messages are generated and broadcasted by processing RT observation/navigation data streams from AUSCORS at the server side. At the user side, RT PPP is realized by processing RT data streams and the RT correction messages received. RT clock offsets, for which the accuracy reached 0.07 and 0.25 ns for GPS and BeiDou, respectively, can be determined. Based on these corrections, an accuracy of 12.2, 30.0 and 45.6 cm in the North, East and Up directions was achieved for the BeiDou-only solution after 30 minutes while the GPS-only solution reached 5.1, 15.3 and 15.5 cm for the same components at the same time. A further improvement of 43.7, 36.9 and 45.0 percent in the three directions, respectively, was achieved for the combined GPS/BeiDou solution. After the initialization process, the North, East and Up positioning accuracies were 5.2, 8.1 and 17.8 cm, respectively, for the BeiDou-only solution, while 1.5, 3.0, and 4.7 cm for the GPS-only solution. However, we only noticed a 20.9% improvement in the East direction was obtained for the GPS/BeiDou solution, while no improvements in the other directions were detected. It is expected that such improvements may become bigger with the increasing accuracy of the BeiDou-only solution. [less ▲]

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See detailA First Evaluation of the new GNSS Station Installations at the Tide Gauges of Walvis Bay and Lüderitz in the Republic of Namibia
Teferle, Felix Norman UL; Combrinck, Ludwig; Botha, Roelf et al

Poster (2016, February 11)

During September 2015 the Hartebeesthoek Radio Astronomy Observatory in collaboration with the University of Luxembourg installed two state-of-the-art continuous GNSS stations adjacent to the tide gauges ... [more ▼]

During September 2015 the Hartebeesthoek Radio Astronomy Observatory in collaboration with the University of Luxembourg installed two state-of-the-art continuous GNSS stations adjacent to the tide gauges of Walvis Bay and Lüderitz in the Republic of Namibia. These installations are the culmination of a four-year effort to get the stations established and the help of the Namibian Port Authority in this endeavour is much appreciated. The tide gauge at Walvis Bay (Global Sea Level Observing System (GLOSS) number 314) has a record in the Permanent Service for Mean Sea Level (PSMSL) Revised Local Reference (RLR) database (number 914) dating back to 1958 (data completeness 54%). The tide gauge at Lüderitz is not a GLOSS station but also has a PSMSL RLR record (number 911) since 1958 (data completeness 67%). Both tide gauges currently use a radar measurement unit and are operated by the Hydrographic Office of the South African Navy. They are the only sea level observations along a more than 3000 km stretch of the West African coast from Pointe Noire in the Republic of the Congo to Port Nolloth in the Republic South Africa, hence they form an important data source for sea level studies. The two continuous GNSS stations record observations from all visible GNSS satellites (GPS, GLONASS, BDS and Galileo) with a 1 second recording interval. The current installations support hourly data downloads, which are sufficient for most activities within the IGS, while the data have great potential to contribute not only to the TIGA working group but also to MGEX. In this study we present the first evaluation of the quality of the GNSS observations from the two new continuous GNSS stations for the first three months of operation. In the future we plan to make the data available to the scientific community. [less ▲]

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