Influence of Time Variable Errors on the GPS Measurement Accuracy

The paper presents that the total measurement error is treated as a random process in time where the error is structurally decomposed into three groups due three different sources. The first group contains time variable errors due to tropospheric-ionospheric influences, , the second one time variable errors due to quasi-stationary refraction blocks, , whereas the third group contains purely random errors - random process noise. In the paper it is claimed that these two groups of time dependent errors determine the accuracy of the GPS measurements, i. e. that they are two principal components of the GPS measurement variances.