Your Phone as a Personal Emergency Beacon: A Portable GSM Base Station to Locate Lost Persons

Access to emergency numbers such as 911 or 112 is generally universally available to cell phone users. Nevertheless, emergencies may occur in areas without cell phone coverage, for example, in remote areas frequented by climbers or hikers. In this article, we describe the design, development, and evaluation of a global system for mobile communications (GSM) base station that can be placed in a vehicle (car, plane, helicopter, etc.) to locate a lost person with an active GSM phone. The system includes the resources to provide a good estimation of the location of the phone, allowing the rescue team to significantly narrow its search and to establish communication with the person where possible, as the system also provides GSM coverage.