Blind Mobile Positioning in Urban Environment Based on Ray-Tracing Analysis

A novel scheme is described for determining the position of an unknown mobile terminal without any prior information of transmitted signals, keeping in mind, for example, radiowave surveillance. The proposed positioning algorithm is performed by using a single base station with an array of sensors in multipath environments. It works by combining the spatial characteristics estimated from data measurement and ray-tracing (RT) analysis with highly accurate, three-dimensional terrain data. It uses two spatial parameters in particular that characterize propagation environments in which there are spatially spreading signals due to local scattering: the angle of arrival and the degree of scattering related to the angular spread of the received signals. The use of RT analysis enables site-specific positioning using only a single base station. Furthermore, our approach is a so-called blind estimator, that is, it requires no prior information about the mobile terminal such as the signal waveform. Testing of the scheme in a city of high density showed that it could achieve 30m position-determination accuracy more than 70% of the time even under non-lineof-sight conditions.