| Summary: | 碩士 === 國立成功大學 === 測量工程學系 === 81 === The precise GPS satellite orbits play a quite important
role for the application of GPS to high accurate long baseline
solution or plate tectonic motion. It is true that we will face
some difficulties in orbit determination, such as how to use
correct initial values for position and speed of satellite and
what is the perfect force models acting upon satellite. In
addition, orbital arc length will also affect adaptability of
models used. The research concentrates on daily orbital arc
adjustment using P-Code pseudorange. The methods of orbit
adjustment are include the Weighted Least Square Method and
Hill's function Method. The effect of using different
regional tracking net- works is also evaluated. Based on the
results from the tracking data experiments, it is not
significant to detect errors of force models of daily
orbital arc. This implies errors of daily arc can be improved
by only adjusting initial values. In addition, using adaptive
regional tracking network, such as enclosing the Pacific Ocean
region including Taiwan, can reach orbit accuracy at better
than 0.5ppm level (related SIO precise ephemeris).
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