US 5,515,419 · Granted 1996-05-07
The 1996 Patent That Turned Your Phone Into a Personal Safety Tracker
Your phone can automatically call for help and tell rescuers where you are. This patent describes how a mobile phone detects emergencies, sends a distress signal through the cellular network, and includes location clues from nearby cell towers so emergency services can find you fast.
The plain-English version
What it protects
The claim covers a mobile phone that detects emergency situations, generates a distress signal automatically, and transmits that signal to a monitoring station along with location identifying data collected from the wireless transceivers nearby. What's protected here is the combination of the emergency detection logic inside the phone, the automatic transmission method, and the specific way location information from cell tower signals gets packaged into the emergency message itself.
Why it matters
This patent represents an early vision of using cellular network infrastructure to locate people in distress. Rather than requiring a separate dedicated device, it embedded location-finding directly into the phone itself by leveraging signals the phone was already receiving from nearby towers. This approach laid groundwork for modern emergency location services built into phones today, which help 911 dispatchers reach people in crisis faster than ever before.
Real-world use
When someone presses an emergency button on their phone or the device detects a sudden impact, the phone can automatically alert responders and relay its approximate location based on which cell towers it's connecting to in that moment.
Original USPTO abstract
A tracking system for tracking a portable or mobile phone unit utilizes an array of fixed wireless signal transceivers forming part of a wireless telephone system. The phone unit includes a processor for generating an emergency signal on detection of an emergency condition and transmitting the emergency signal to a remote monitoring station via the wireless telephone network. The emergency signal includes identifying information for identifying the phone unit, as well as identifying or control channel signals received by the phone unit from adjacent wireless signal transceivers which are retransmitted as part of the emergency signal to be used at the remote monitoring station to compute an approximate location of the phone unit.
Patent details
- Publication number
- US 5,515,419
- Filing date
- 1994-08-02
- Grant date
- 1996-05-07
- Assignee
- Trackmobile
- Inventor(s)
- SHEFFER; ELIEZER A.
- CPC class
- H04W64/00
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