Emergency response system

• US 6,032,035 A
• Filed: 05/21/1997
• Issued: 02/29/2000
• Est. Priority Date: 05/21/1997
• Status: Expired due to Fees

• Current Assignee: March Networks Corporation (Infinova (Canada) Ltd.)
• Original Assignee: Elcombe Systems Ltd. (Infinova (Canada) Ltd.)
• Inventors: Webster, Robert K., Whitbread, J. Raymond, Dufour, Real, Danis, Andre J.
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): Tran, Pablo N.
• Application Number:
  US08/859,714
• Time in Patent Office: 1,014 Days
• Field of Search: 455/404, 455/567, 455/423, 455/424, 455/425, 455/67.1, 455/67.4, 379/37, 379/39, 379/40, 379/41, 379/42, 340/539, 340/571, 340/572
• US Class Current: 455/404.2
• CPC Class Codes: G08B 21/02 Alarms for ensuring the safety of persons
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence

Abstract

A portable transmitter unit for an emergency response system is provided with a receiver to detect, decode and dynamically store location codes transmitted by strategically placed high frequency AM transmitters. The location code is attached to the stored identity code assigned each portable unit. The combined code is transmitted via a radio signal to an emergency response station upon activation of a switch on the unit by a user requiring assistance.

Claims

1. An emergency monitoring and alerting system comprising:

a plurality of high frequency, amplitude modulation transmitters strategically placed within an area to be monitored each having a stored location code representing a specific location of said transmitter and transmitting means for transmitting said code via a high frequency am spread spectrum frequency hopping technique;

a portable transmitter/receiver unit for use by a user of the system, said transmitter/receiver unit having a high frequency am receiver to periodically detect, decode and store said location code transmitted thereto by said transmitter;

processing means including storage means to store a unique identity code respecting said transmitter/receiver unit, said processing means also having means to attach said location code to said identity code and to transmit the combined code in response to a command by said user, said transmitter/receiver unit having timing means to test for coded information on a periodic basis and to defer testing for a set interval upon receipt of said location code; and

a local receiver for receiving said combined code and determining the identity and the location of said unit and if said code represents a location within a preset group of locations forwarding said data to a central monitoring station, otherwise ignoring said code.

2. An energy monitoring and alerting system as defined in claim 1 wherein said timing means defers testing for coded information for an of about one minute after coded information has been received.

4. A portable transmitter/receiver unit as defined in claim 1 having means to compare new coded location information from another of said local transmitters with coded location information attached to said identity code and if said new coded location information is different to replace said code attached to said identity code.

5. A high frequency, amplitude modulation, (am) transmitter for providing a location code to a portable, emergency transmitter/receiver unit as defined in claim 1, said transmitter having memory means to store a predetermined location code and transmitting means to transmit said location code utilizing a pseudo-random, spread spectrum, frequency hopping transmission technique wherein the range of frequency selected covers a sub-range of 15 MHz of a 902 MHz to 928 MHz Industrial, Scientific and Medical (ISM) frequency band.

6. A portable transmitter/receiver unit as defined in claim 1 wherein said unique code assigned to said unit consists of a set number of data bits that is different than the number of bits comprising said coded location information and is transmitted to said unit through said high frequency am receiver.

7. A portable transmitter/receiver unit as defined in claim 1 wherein said receiver tests for coded information for an interval of 5 milliseconds and a period of 100 milliseconds.

8. A portable transmitter/receiver unit as defined in claim 6 wherein said unique code assigned to said unit is data word having at least 14 bits and said location code is a 6 bit word.

9. A portable transmitter/receiver unit as defined in claim 8 wherein said unique code assigned to said unit is stored in three separate locations in said memory means.

3. A portable transmitter/receiver unit for an emergency alerting system comprising:

memory means for storing an identity code which is unique to said unit;

processing means for selectively retrieving said identity code from said memory means;

transmitting means for transmitting data including said identity code upon activation of a switch on said unit;

a high frequency, amplitude modulation (am) receiver having detector means for receiving and interpreting coded location information received via a high frequency am signal from one of a plurality of local high frequency am transmitters, said receiver testing for coded information on a periodic basis; and

accessing means for accessing said processing means and attaching said coded location information to said identity code to be transmitted therewith, said detector means including means to selectively turn off said receiver for a preset interval upon receipt of said coded location information.

10. A local receiver for receiving coded information from a portable transmitter/receiver unit of an emergency alerting system, said coded information including an identity code respecting the portable transmitter/receiver unit from which the code is received and a location code representing an approximate location of said portable transmitter/receiver, said local receiver including processing means to evaluate said location code and if said code is within a set of predetermined codes said information is forwarded to a central control station otherwise it is ignored.