Efficient star-topology solving local minima for geolocation in real UMTS networks: an experimental assessment with real data

Hyperbolic radio-location systems possess intrinsic uncertainty that depends on the Node B stations geometry when an iterative positioning algorithm like for instance, Levenberg–Marquardt,is employed to determine an estimate of the mobile station position. This inherent uncertainty arises from the presence of particular areas susceptible to contain local minima inside of it. In this paper, we investigate an optimal geometry for the Node B stations to be involved in such an iterative method. The key factor is to seek such an optimal configuration in the real map to be analysed with the purpose of avoiding any local minima. In this manner, errors in the positioning algorithm are only due to multipath environment and co-channel interference, ensuring that local minima do not affect the result offered by the positioning method. A provisional patent application based on this method has been filed