Accuracy of GPS Phase and Code Observations in Practice

In order to examine the accuracy of GPS observations, both precision and biases have to be taken into account. The precision of a GPS observation reflects its stochastic variability and is described by the standard deviation. Biases are non-random effects in the GPS observations (like for instance multipath). In this article these two factors will be examined for seven GPS receivers. In order to examine precision and multipath, an experiment with both zero and short baselines was carried out, which will be briefly discussed. As results, time series of residuals will be presented, on the one hand to give a picture of the precision capabilities of GPS receivers at present, and on the other hand to examine the impact of non-modeled effects like multipath on GPS observations in practice.