Patent ID: 8629802

Claim:
A method of determining the location of a mobile terminal in a given area, comprising the steps of: including said mobile terminal both in a satellite-based positioning system and in a cellular communication system, whereby said mobile terminal is adapted to receive satellite signals from said satellite-based system and to be covered by at least one cell of said cellular communication system; determining a first set of values for positioning coordinates of said mobile terminal on the basis of information related to said cellular communication system, said first set of values comprising: approximate bi-dimensional positioning coordinates of said mobile terminal; and an estimate of an altitude coordinate of said mobile terminal; determining a search area for positioning coordinates of said mobile terminal based on said satellite signals and said estimate of said altitude coordinate; providing a geographical data base comprising data base items associated with a given set of bi-dimensional positioning coordinates of said mobile terminal in said search area corresponding to values for said altitude coordinate; identifying a new set of values for said positioning coordinates, wherein identifying the new set of values comprises: effecting, based on said information related to said cellular communication system, bi-dimensional positioning coordinates of said mobile terminal within said search area; accessing said geographical data base; and associating to the bi-dimensional positioning coordinates of said mobile terminal a corresponding value for said altitude coordinate; determining the distance between the first set of values and the new set of values as available before and after the current iteration step; comparing said distance with a threshold indicative of the degree of accuracy pursued in the location action; and if said distance is higher than said threshold, running a further iteration step wherein said search area is further re-defined on the basis of said satellite signals from said satellite-based system and the latest value available for said altitude coordinate and said steps of effecting bi-dimensional positioning coordinates, accessing said geographical data base, and associating to the bi-dimensional positioning coordinates of said mobile terminal a corresponding value for said altitude coordinate are further repeated, wherein said step of effecting bi-dimensional positioning coordinates is effected over said further re-defined area.