Abstract:
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Hybridization is a hot topic in the location field. Since
there is no universal location technique that is capable of
positioning in indoor and outdoor environments, two or more
techniques must be coupled to produce a complete location
solution. Accordingly, information on the availability of each of
the techniques being coupled is of great relevance in the design
and implementation stages of the location system. In public
cellular networks, this coupling usually involves a terrestrial
triangulation technique (e.g. E-OTD, OTDOA) and a GNSSbased
technique (e.g. A-GPS). The purpose of this paper is
twofold. Firstly, it presents a software tool developed for studying
the availability of location systems in certain environments,
which is able to capture and present information on the
availability of satellites in the NAVSTAR constellation (i.e. GPS)
and the GSM/GPRS base stations being received in the user
terminal. Secondly, it studies the coverage of these techniques
using the tool described. Availability data for three routes in an
urban environment are gathered and analyzed. In two of them,
GPS did not cover 100% of the route, which demonstrated the
need to couple the technique with another terrestrial technique to
cope with the “dark” areas. |