Near real-time prediction of Zenith Tropospheric Delays for position estimation over long-baseline CORS network

Wang, Charles & Feng, Yanming (2009) Near real-time prediction of Zenith Tropospheric Delays for position estimation over long-baseline CORS network. In The Institute of Navigation, ION GNSS 2009, 22-25 September 2009, Savannah International Convention Center, Savannah, Georgia.

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This paper presents the preliminary results in establishing a strategy for predicting Zenith Tropospheric Delay (ZTD) and relative ZTD (rZTD) between Continuous Operating Reference Stations (CORS) in near real-time. It is anticipated that the predicted ZTD or rZTD can assist the network-based Real-Time Kinematic (RTK) performance over long inter-station distances, ultimately, enabling a cost effective method of delivering precise positioning services to sparsely populated regional areas, such as Queensland.

This research firstly investigates two ZTD solutions: 1) the post-processed IGS ZTD solution and 2) the near Real-Time ZTD solution. The near Real-Time solution is obtained through the GNSS processing software package (Bernese) that has been deployed for this project. The predictability of the near Real-Time Bernese solution is analyzed and compared to the post-processed IGS solution where it acts as the benchmark solution. The predictability analyses were conducted with various prediction time of 15, 30, 45, and 60 minutes to determine the error with respect to timeliness. The predictability of ZTD and relative ZTD is determined (or characterized) by using the previously estimated ZTD as the predicted ZTD of current epoch.

This research has shown that both the ZTD and relative ZTD predicted errors are random in nature; the STD grows from a few millimeters to sub-centimeters while the predicted delay interval ranges from 15 to 60 minutes. Additionally, the RZTD predictability shows very little dependency on the length of tested baselines of up to 1000 kilometers. Finally, the comparison of near Real-Time Bernese solution with IGS solution has shown a slight degradation in the prediction accuracy. The less accurate NRT solution has an STD error of 1cm within the delay of 50 minutes. However, some larger errors of up to 10cm are observed.

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ID Code: 31010
Item Type: Conference Paper
Refereed: No
Keywords: Near Real-Time ZTD, Long Range RTK, CORS, Precise Positioning
Subjects: Australian and New Zealand Standard Research Classification > EARTH SCIENCES (040000) > ATMOSPHERIC SCIENCES (040100)
Divisions: Past > QUT Faculties & Divisions > Faculty of Science and Technology
Copyright Owner: Copyright 2009 [please consult the authors]
Deposited On: 18 Feb 2010 21:26
Last Modified: 09 Jun 2010 14:22

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