Identification of GNSS Measurement Error: From Time to Elevation Dependency

This article deals with the identification of the Global navigation satellite system measurement error properties. For this purpose, an extended version of the measurement difference method, which does not rely on knowledge of the state dynamics, is developed. The method provides elevation-dependent estimates of the pseudorange and pseudorange-rate measurement error properties in the form of both; the autocovariance function and the parametric model including the correlation time constants. The identification method is thoroughly discussed and verified using simulated and real Galileo E5b data and the identified models are utilized in the positioning solution. The identified measurement model improves the positioning accuracy by more than 20 percent.