HR: 1340h
AN: G43A-0919    [Abstracts]
TI: Tropospheric path delay corrections for vertical positioning precision by using GPS
AU: * Wang, C
EM: carlwang.cv87g@nctu.edu.tw
AU: Liou, Y
EM: yueian@csrsr.ncu.edu.tw
AB: Recent scientific interest on constantly enhancing positioning accuracy by the Global Positioning System (GPS) is a challenging task among a variety of research tasks. The positioning accuracy of the GPS surveying has been improved considerably during the past two decades. The main error sources have been reduced substantially, if not eliminated. However, troposhpeic influence with its high temporal and spatial variability appears to be one of the existing major error sources. It is hence an increased interest among GPS researchers to reduce the tropospheric influence. Two techniques have been commonly implemented to correct the tropospheric path delay in GPS data processing. The first technique, known as parameter estimation, characterizes the path delay with empirical models and the parameters of interest are determined from the GPS measurements. The second strategy, termed as external correction, involves independent path delay measurements. The present study is an integration of both techniques in which the parameter estimation and external correction are used to correct the path delay for 10~365 km range baselines. Twenty-four zenith path parameters and tropospheric gradients have been set in 24 hours solution for parameter estimation strategy. Measurements from meteorological instruments and water vapor radiometers are applied in the GPS data processing, separately, as an external strategy of present research work. Interesting results have been found, indicating more stable repeatability in baseline when the external correction strategy is applied especially with the inclusion of water vapor radiometer data. The offset on the order of centimeter is found in the baselines determined by the two strategies. On the other hand, parameter estimation exhibits more stable in terms of GPS height repeatability. The offset in the GPS height determined by the two strategies is on the order of few centimeters.
DE: 1204 Control surveys
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1243 Space geodetic surveys
SC: Geodesy [G]
MN: 2007 Fall Meeting