Approach of virtual observations generation of a multi-reference GPS station network

The generation of virtual reference station observations to relay the corrections to the rover receiver for use with standard RTK software is one of important architectures of reference station networks RTK positioning. The approach of virtual observations generation based on a multi-reference GPS station network is presented in this paper. Ambiguities for the baselines in the reference network are determined firstly. The inter-reference-station differential spatially-correlated errors are estimated using highly accurate coordinates of the reference stations and resolved ambiguities. These spatially-correlated errors are interpolated among the network region as corrections. These network-generated corrections are used to correct the zero-differential observables of one reference station, which is usually the closest one to the rover (the so-called primary reference station). These corrected zero-differential observables, named virtual observations, are processed using conventional single reference station differential GPS algorithms. A test conducted using regional reference networks in Jiangsu(China) demonstrates the effectiveness of the approach to reduce the time to integer ambiguity resolution, and to increase the distance over which centimeter level accuracies can be achieved.