Communication system

• US 4,601,064 A
• Filed: 10/03/1984
• Issued: 07/15/1986
• Est. Priority Date: 01/13/1983
• Status: Expired due to Term

• Current Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Original Assignee: Fisher Berkeley Corporation
• Inventors: Shipley, Robert T.
• Primary Examiner(s): ORSINO JR, JOSEPH
• Application Number:
  US06/658,052
• Time in Patent Office: 650 Days
• Field of Search: 455/600, 455/603, 455/605, 455/606, 455/607, 455/608, 455/617, 455/618, 455/619, 455/604, 340/825.44, 340/825.47, 340/825.48, 340/825.49
• US Class Current: 398/127
• CPC Class Codes: G06K 7/1097 Optical sensing of electronic memory record carriers, such as interrogation of RFIDs with an additional optical interface
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08B 25/014 Alarm signalling to a central station with two-way communication, e.g. with signalling back
• CPC Class Codes: H04B 10/1149 Arrangements for indoor wireless networking of information
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04M 3/42229 Personal communication services, i.e. services related to one subscriber independent of his terminal and/or location diverting calls from one subscriber to another subscriber, i.e. two different subscriptions H04M3/54; selecting arrangements in intelligent networks H04Q3/005
• CPC Class Codes: H04M 9/00 Arrangements for interconnection not involving centralised switching
• CPC Class Codes: Y10S 379/913 Person locator or person-specific

Abstract

A communications system provides for the location or tracking of persons or objects to automatically establish two-way conversation with the person located via an associated intercom or telephone system. The locating system provides each person or object to be located with an infrared pulse transmitter which operates continuously automatically and repetitively. It requires no action on the part of the person being monitored. The system is cost effective and accurate by reason of the infrared pulse code utilized. It includes a relatively short pulse width for low power consumption, a pulse code which has error detecting bits, and use of a high pulse output power to distinguish over ambient noise.

Claims

1. In a personnel locating system for use in a facility having a plurality of rooms having doorways therein, a plurality of portable transmitters, each including a battery and each generating automatically and repetitively a unique signal consisting of pulses of infrared radiation, a plurality of fixed receivers positioned to cover different rooms at a facility, each room having a receiver therein positioned to accept infrared radiation from a substantial portion of the volume of the room, each receiver being capable of repetitively sensing and storing any of said unique signals generated by said transmitters during the entire time said transmitters are located anywhere in the facility including when located within a room, means for polling said receivers to determine which of said unique signals are stored at said receivers to ascertain repetitively the location and identity of each transmitter in each room and means associated with the transmitters for ensuring that the locations and identities of any of said transmitters will not be lost at any time even though occasional collisions of the unique signals from said transmitters may occur.

2. A system as in claim 1 wherein the power of said pulses is sufficient to allow said pulses to be reflected off objects in a room and off the walls of a room and still be sensed by said receiver, said pulses also being of a low duty ratio to minimize energy drain on said battery.

3. A system as in claim 1 wherein each transmitter transmits its unique signal with a unique transmit interval which is not a multiple of another transmit interval whereby the collision of signals from said any transmitters will occur frequently.

4. A system as in claim 1 wherein each of said receivers includes optical filter means for filtering out visible light and ultraviolet energy and additional electrical filter means for controlling high frequency response.

5. A system as in claim 1 wherein each of said receivers include means for storing at least one of said unique infrared signals.

6. A system as in claim 1 wherein the infrared signal includes an error detection code.

7. A system as in claim 1 wherein said infrared radiation has a wavelength of substantially 880 nanometers.

8. A system as in claim 1 wherein each receiver has a unique location address corresponding to said area in said facility in which it is located, said polling means also polling said receivers for said location addresses.

9. A system as in claim 8 wherein said polling means includes a central computer for placing in memory said location addresses of said receivers and the unique signals associated with said transmitters.

10. A system as in claim 9 together with means for erasing said memory if it has not been updated within a predetermined time interval.

11. A system as in claim 1 together with means for determining and recording the absence from the system of a said unique infrared signal if such signal has not been sensed within a predetermined time interval.

12. A system as in claim 1 together with telecommunication means for automatically establishing an audio connection to at least certain of said rooms in said facility.

13. A system as in claim 1 wherein each transmitter includes means operable by the personnel for altering the unique infrared signal to indicate a preselected condition.

14. A system as in claim 1 wherein said means for polling continuously senses, on a cyclic basis, which of said unique signals are stored at said receivers.

15. In a method for locating personnel using infrared energy in premises including a plurality of rooms defined by walls impermeable to infrared energy and providing surfaces for reflecting infrared energy thereto and having entrances through which personnel can pass by the use of a plurality of portable battery powered infrared transmitters with each transmitter emitting repetitively and automatically a coded train of infrared pulses which is unique to that transmitter and a plurality of infrared receivers, the method comprising causing each of the personnel to be located to carry an assigned transmitter, positioning at least one receiver in a room so it is capable of accepting infrared radiation from a substantial portion of the volume of said room and so that it is capable of receiving coded trains of pulses emitted by any transmitter in the room either directly by line-of-sight or by reflection from surfaces of objects in that room or from the surfaces of the walls of that room during the entire time the transmitter is located in the room, polling the receiver repetitively, utilizing the information obtained by polling the receiver for ascertaining the location and identity of each transmitter, repetitively verifying the location and identity of each transmitter in each room during the entire time a transmitter is located anywhere in the room and ensuring by use of the transmitters that the locations and identities of any of said transmitters will not be lost at any time even though occasional collisions of the coded trains of pulses from said transmitters may occur.

23. A method as in claim 15 wherein the coded train of pulses have generating pulses of sufficient power so that when they are reflected by surfaces of objects in the room or surfaces of walls of the room they can still be sensed by the receiver in the room.

24. A method as in claim 23 wherein the coded train of pulses are generated with a low duty cycle to minimize power requirements.

16. In a personnel locating system of the type utilizing infrared energy and for installation in premises including a plurality of separate rooms defined by walls impermeable to infrared energy and providing surfaces for reflecting infrared energy, the rooms having entrances thereto through which personnel can pass, a plurality of portable battery powered infrared transmitters, each transmitter having circuitry for emitting repetitively and automatically a coded train of infrared pulses which is unique to that transmitter, said transmitters being of a size so that an assigned transmitter can be carried by each of the personnel, a plurality of infrared receivers, each of the rooms in the premises to be monitored having at least one receiver therein positioned to accept infrared radiation from a substantial portion of the volume of the room, the receiver in the room being capable of receiving coded trains of pulses emitted by any transmitter in the room either directly from the transmitter by line-of-sight or by reflection from the surfaces of the objects in that room or from surfaces of the walls of that room during the entire time that the transmitter is located anywhere in the room, each receiver having an address, a control console, means establishing communication with each receiver in the system and the console, said console having associated therewith a computer memory for receiving and storing information received from the receivers, said control console including means for automatically polling all of said receivers repetitively and for storing the information in the computer memory, said control console having means associated therewith for indicating the location and identity of each transmitter by utilizing the information in the memory obtained by polling the receivers whereby the location and identity of each transmitter in each room is repetitively verified during the entire time a transmitter is located anywhere in a room in the premises and means associated with the transmitters for ensuring that the locations and identities of any of said transmitters will not be lost at any time even though occasional collisions of the coded trains of pulses from said transmitters may occur.

17. A system as in claim 16 wherein said control console includes means for erasing the information in said memory with respect to any transmitter if the information with respect to that transmitters has not been updated within a predetermined time interval.

18. A system as in claim 16 wherein said control console includes means for recording the absence of a transmitter if a signal from the transmitter has not been sensed by a receiver within a predetermined interval.

19. A system as in claim 16 together with a telephone located in at least certain rooms and means associated with the control console for selectively ringing the telephone most closely adjacent to a predetermined transmitter.

20. A system as in claim 16 wherein said pulses of infrared radiation have a duty cycle at least an order of magnitude less than one percent.

21. A system as in claim 16 wherein each transmitter transmits its unique signal with a unique transmit interval which is not a multiple of another transmit interval.

22. A system as in claim 16 wherein the receivers are polled sequentially in an endless loop.