Frontiers in the combination of space geodetic techniques

Co-location sites are one of the key elements in the combination of the reference frames of different space geodetic techniques. They are fundamental for a consistent datum realization of the combined networks. This paper deals with a new strategy for the selection and implementation of local tie information and demonstrates how the ERP as common parameters of the different geodetic space techniques can be used for local tie validation. As one result of the new strategy it is shown, that only a small set of very consistent co-location sites should be used for the combination. Additionally, the capability of a combination using only the lengths of the local tie vectors is investigated. The strengths and weaknesses of this method are characterized.