GPS data processing with equivalent observation equations

A unified GPS data processing method based on equivalent observation equations is proposed. The theoretic background of this method is given in detail. By selecting the unknowns to be eliminated as vector of zeros, i.e. the satellite clock errors, all clock errors, the clock and ambiguity parameters or user-defined unknowns, the equivalent observation equations can be formed. These equations are equivalent to the zero-, single-, double-, triple- or user-defined differenced equations. The advantages of the method are that the various GPS data processing methods are unified to a unique one, whereas the observation vector remains the original one and the weight matrix keeps the un-correlated diagonal form. Using this equivalent method one may selectively reduce the number of unknowns without having to deal with the correlations. Several special cases of single, double and triple difference are discussed in detail to illustrate the theory. Electronic Publication