Abstract：In global navigation satellite system (GNSS) data processing, the correct stochastic modelcan be applied to improve the positioning accuracy and efficiency.In practice, the variances of raw GNSS measurements are associated with satellite elevation angles, least-squares variance component estimation is applied to evaluate three unknown parameters of the exponential model on the basis of double differenced GPS measurements collected by Trimble R8 receivers, and the positioning accuracy is analyzed compared with the identical weight model and the commonly exponential model.The results show that the proposed stochastic model is more accurate and the elevation model is not necessarily better than the identical weight model if the parameters are not appropriately specified.Therefore, it should choose the realistic stochastic model considering the type of receiver and observation.

Keyword：global navigation satellite system (GNSS) ;stochastic model;satellite elevation model;exponential model;least-squares variance component estimation (LS-VCE)