Modelling the noise in GPS coordinate time series

By investigating the velocity uncertainties in GPS coordinate time series we have to be aware of the fact that we also need good knowledge of the models that best describe the presents of the noise in the GPS time series coordinates. For a proper noise mode we have to take into account all the stochastic effects and to be able to classify the types of the noise source that will affect our results like: white noise, flicker noise, and random walk. The paper is presenting a case study in which we have used spectral analysis and Maximum Likelihood Estimation to best describe the presence of the noise. In the study we have estimated both annual and semiannual signals and also the GPS draconitic period harmonics which capture the unmodelled periodic effect.