Map-based mobile positioning system

Abstract

As operators, in the U.S., strive to meet the FCC mandates and regulations continue. Some operators have been asking for waivers, for not being able to meet Phase II of E911, which calls for a strict location of mobile users upon initiating 911 calls from their mobile stations (MS). So far, no work has been claimed to meet the FCC–E911 tolerances for locating mobile phones without GPS assistance. In this paper, a mobile positioning system (MPS) is proposed based on a map-matching algorithm. Using the triangulation or a trilateration technique, the Cell of Origin, Time of Arrival, and Time Difference of Arrival, the mobile is first located within a specified area of about 500x500 squared meters in a GSM network and within a specified area of about 244x244 squared meters in an IS-95 network. The received powers and channel IDs from different BTSs at discrete locations are initially collected and stored in a database, leading to “unique” signatures within a “sufficiently” small neighborhood. The mobile location is resolved by correlating the received power from different BTSs to the database. Experimental work is presented and analyzed to examine the feasibility of applying the proposed MPS to meet the FCC-E911 tolerances.