Method and apparatus for precisely locating a mobile unit

• US 6,314,281 B1
• Filed: 07/14/1998
• Issued: 11/06/2001
• Est. Priority Date: 07/14/1998
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Chao, Jim Jingfu, Pittampalli, Eshwar
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): PERSINO, RAYMOND B
• Application Number:
  US09/114,840
• Time in Patent Office: 1,211 Days
• Field of Search: 455/404, 455/456, 455/414, 455/466, 342/386, 342/52, 342/57, 342/58, 340/825.49
• US Class Current: 455/404.2
• CPC Class Codes: G01S 1/68 Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• CPC Class Codes: G08B 25/016 Personal emergency signalling and security systems emergency non-personal manually actuated alarm activators G08B25/12
• CPC Class Codes: H04M 2207/18 wireless networks
• CPC Class Codes: H04M 2242/04 for emergency applications
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

A method and system for locating a precise physical location of a distressed enhanced mobile unit comprises use of a distress notification signal. In one embodiment, a distressed mobile unit emanates a predefined distress notification signal upon completion of an emergency services (e.g. 911) call. The distress notification signal is received by a rescue squad enhanced mobile unit in nearest proximity to the distressed enhanced mobile unit. The rescue squad enhanced mobile unit uses the distress notification signal to identify the location of the distressed mobile unit. In some embodiments, an audible distress signal is also issued by the distressed enhanced mobile unit so that rescue personnel can follow the audible signal to a user in distress.

Claims

1. In a wireless telecommunications system serving mobile units, a method for identifying a location of a particular mobile unit comprises:

activating a distressed enhanced mobile unit to emanate a distress notification signal;

locating a rescue squad enhanced mobile unit to respond to the distressed enhanced mobile unit; and

notifying the rescue squad enhanced mobile unit of a frequency of the distress notification signal so that the distress notification signal may be used to locate the distressed enhanced mobile unit.

2. The method of claim 1 further comprising the distress enhanced mobile unit completing a call to an emergency service organization prior to the step of activating the distressed enhanced mobile unit to emanate the distress notification signal.

3. The method of claim 1 further comprising the distressed enhanced mobile unit emanating an audible distress notification signal.

4. The method of claim 1 wherein locating a rescue squad enhanced mobile unit comprises the step of:

locating the rescue squad enhanced mobile unit in nearest proximity to the distressed mobile unit.

5. The method for claim 1 further comprising interrupting the distress notification signal to allow a non-emergency call to be placed by the distressed enhanced mobile unit.

6. The method of claim 1 further comprising determining a strength of the distress notification signal and using the strength of the distress notification signal to locate the distressed enhanced mobile unit.

7. An enhanced mobile unit served by a wireless telecommunications system comprising:

a central processor interconnected to a memory;

a radio frequency transceiver interconnected to the central processor;

means for activating a distress notification signal upon termination of an emergency services call; and

wherein the radio frequency transceiver interrupts broadcast of the distress notification signal upon origination of a call.

8. The mobile unit of claim 7 further comprising an audio transmitter for emanating an audible distress signal in conjunction with the distress notification signal.

9. The mobile unit of claim 7 further comprising a navigation system interconnected to the central processor to determine a location of the enhanced mobile unit.

10. A rescue squad enhanced mobile unit associated with a wireless telecommunications system comprising:

a central processing unit interconnected to a memory;

a radio transceiver interconnected to a central processing unit for receiving distress notification signals from a distressed mobile unit; and

an audio receiver interconnected to the memory unit for receiving audible tones generated from the distressed mobile unit.

11. The rescue squad enhanced mobile unit of claim 10 further comprising:

a received signal strength indicator for responding to the distress notification signals.

12. A wireless telecommunications system comprising:

a mobile switching center that serves an enhanced mobile unit;

the enhanced mobile unit being adapted to interconnect to the mobile switching center via a base station;

wherein the mobile switching center transmits a distress notification activation signal to the enhanced mobile unit so that the enhanced mobile unit emanates a radio frequency distress signal;

wherein the mobile switching center transmits to a rescue squad enhanced mobile unit information allowing the rescue squad enhanced mobile unit to receive the radio frequency distress signal; and

wherein the information includes instructions to tune to a particular frequency.