9560808 Parl This Small Business Innovation Research Phase I project involves an investigation into the application of a new, innovative, passive radio-based geolocation technique, developed by the proposing firm, to the problem of locating and tracking cellular telephones and other emerging wireless personal communication devices without requiring modification to the mobile phones. The new signal processing method is based on a technique developed in part under NIH funding, which was designed for use in locating wandering elderly and mental patients. The technique employs a maximum-likelihood estimation of the emitter location which is based on joint estimation of signal parameters at multiple existing cellular base stations. The proposed approach offers a potential order of magnitude increase in location accuracy over existing techniques and also promises to permit location of in-building emitters. The new technique promises to be inexpensive in implementation and will not require costly wide-band dedicated line connection to a central processing facility, as do some current techniques, nor will it require signal processing at the mobile terminal, as do existing GPS and Loran-C location determination devices. It is proposed that the new signal processing technique be adapted to use existing control signals that are periodically emitted from cellular telephones; such proposal ensures that no modification of the cellular telephones or existing cellular infrastructure is required to implement a final system. Phase I of the program comprises the development a computer simulation of a multiple base station cellular telephone system. The simulation will be used to study the performance in terms of accuracy, building penetration, and required complexity of the proposed technique under various realistic radio propagation conditions. The results will be used to determine the minimum hardware configuration for Phase II prototype implementation. Performance models for the proposed system using cellular telephone transmissions will be developed and implementation costs estimated. The Phase I program will conclude with the preliminary design of the base station hardware, plans for remote monitoring and control of the base station units, and estimation of system costs based on the preliminary design. A competitive analysis comparing the proposed technique to other geolocation techniques and an in-depth commercialization plan will be developed. The proposed geolocation technique will have application in low-cost implementation of enhanced 9-1-1 services to locate wireless telephones in emergency situations, medical condition monitoring/location, low-cost vehicle tracking and navigation systems (including automated dispatch), tracking of mobile computers for network management, child location devices, criminal tracking, pet location devices, stolen vehicle recovery, lost/stolen cellular telephone recovery, and a wide range of Intelligent Transportation System (ITS) location-based service systems.