Using Double Difference Information from Network Solutions to Generate Observations for a Virtual GPS Reference Receiver

Abstract

We develop the theoretical background for generating artificial observations for a virtual reference receiver in post processing mode. We use double difference information from network solutions to correct zero difference observations in a preprocessing clock estimation process and find that the observations can be adjusted on the level of about 4 mm. Using simple ionosphere and troposphere modeling techniques we show how phase observations can be calculated for any location within the network. Full use is made of the ambiguity and ionosphere information from double difference network solutions in order to keep full consistency of the artificial phase observations on the double difference level. The effect of such observations is demonstrated with data from a GPS network in Switzerland. We find that baseline solutions are more precisely determined (e.g. ambiguity resolution) using a virtual receiver at one end with observations constructed with the proposed approach.