Determination of high-precision GPS orbits using triple differencing technique

Precise orbits of the Global Positioning System (GPS) satellites are fundamental constituents of GPS-based space geodesy. Accurate baseline estimates with a precision of one to a few parts in 10⁸ are essential to the study of Earth's dynamics problems. As a by-product of trajectory estimation, high resolution Earth Rotation Parameters (ERPs) can also be determined. A new application of triple differencing for efficient evaluation of GPS orbits in a PC environment is presented here. Initial tests show that this approach is capable of providing orbits that are highly compatible with the results obtained by the International GPS Service for Geodynamics (IGS). This approach allows for completely automated data processing without the overhead of working with very large normal matrices or cycle-slip fixing.