Tag for use with personnel monitoring system

• US 4,952,913 A
• Filed: 12/04/1989
• Issued: 08/28/1990
• Est. Priority Date: 04/15/1986
• Status: Expired due to Term

• Current Assignee: B.I. Incorporated (Geo Group Incorporated)
• Original Assignee: B.I. Incorporated (Geo Group Incorporated)
• Inventors: Ripingill, Allen E. Jr., Pauley, James D.
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): MULLEN, THOMAS J
• Application Number:
  US07/446,212
• Time in Patent Office: 267 Days
• Field of Search: 340/572-576, 340/514-516, 340/539, 340/825.49, 455/100
• US Class Current: 340/573.4
• CPC Class Codes: G06K 19/04 characterised by the shape
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08B 29/046 prevention of tampering with detection circuits

Abstract

A tag for use with an individual monitoring system. The tag is worn by an individual being monitored, preferably on the ankle or leg where it can be concealed by the clothing of the individual. The tag is fully self contained and sealed. The circuits of the tag periodically generate an identification signal that includes an identification code. The identification signal modulates a stable RF signal that is transmitted in bursts of data words to a receiver associated with a field monitoring device (FMD) located at the monitoring location. In turn, the FMD may randomly establish communication with a central processing unit (CPU) located at a central monitoring location. Other information is included in the identification code of the tag, such as information indicating that an attempt has been made to remove the tag from the individual. The tag is held in place near the skin of it'"'"'s wearer by a conductive strap that wraps around the leg or other limb of the individual. Two capacitive electrodes, one of which is realized with the conductive strap, function as the plates of a capacitor, with the body flesh serving as the dielectric material therebetween. By monitoring an alternating signal coupled from one capacitive electrode to the other, a determination can be made as to whether the tag has remained near the body flesh. Further, because the strap is conductive, a signal can be passed therethrough and a determination can be made as to whether the strap has been broken.

Claims

1. A tag for use with an individual monitoring system, said individual monitoring system including means for monitoring the presence or absence of an individual wearing said tag within a defined area, said tag including:

a self-contained power source;

tamper sensing means for sensing any attempt to tamper with the operation of said tag, including any attempt to remove said tag from an individual wearing said tag; and

circuit means coupled to said power source for generating an encoded data signal, said encoded data signal comprising a plurality of bits that make up a preselected code word that identifies a particular tag, and at least one tamper bit that identifies any tamper attempt sensed by said tamper sensing means;

whereby said encoded data signal provides an indication, when generated, of whether the operation of the tag identified by said preselected code word has been tampered with.

2. The tag as set forth in claim 1 wherein said tag further includes:

means for generating and transmitting a radio frequency (RF) signal; and

means for modulating said RF signal with said encoded data signal;

whereby an indication of whether the operation of the tag identified by said preselected code word has been tampered with may be transmitted by said RF signal to a location remote from said tag.

3. The tag as set forth in claim 2 wherein said preselected code word comprises seven bits, and said at least one tamper bit comprises one bit, whereby said encoded data signal comprises an eight bit word.

4. The tag as set forth in claim 1 wherein said tag includes means for holding said tag near the flesh of an individual wearing said tag, and wherein said tamper sensing means includes means for sensing whether said tag is held near human flesh, a tamper attempt being detected whenever the tag is removed away from human flesh.

5. The tag as set forth in claim 4 wherein said tag holding means comprises a strap, and wherein said tamper sensing means further includes means for checking the continuity of said strap, a tamper attempt being detected whenever the continuity checking means indicates the continuity of said strap has been broken.

6. The tag as set forth in claim 5 wherein said at least one tamper bit comprises one bit that is set to indicate a tamper attempt if either:

(1) said means for sensing whether the tag is held near human flesh indicates the tag has been removed away from human flesh;

or (2) said continuity checking means indicates the continuity of said strap has been broken;

whereby said one tamper bit indicates whether any of a plurality of tamper attempts sensed by respective tamper sensing means has been made.

7. A tag for use in a personnel monitoring system comprising:

an enclosed housing adapted to be worn by an individual being monitored by said personnel monitoring system;

means within said housing for generating an identification signal that uniquely identifies said tag;

tamper sensing means within said tag for sensing any attempt to remove said tag from an individual wearing said tag, and for generating a tamper signal in response to such sensing; and

means for combining said identification signal and said tamper signal into an encoded data signal, a first portion of said encoded data signal comprising at least one data bit indicative of said tamper signal, and a second portion of said encoded data signal comprising a plurality of data bits indicative of said identification signal;

whereby the first portion of said encoded data signal provides an indication of whether any attempt has been made to remove the tag identified by the second portion of data bits of said encoded data signal.

8. The tag as set forth in claim 7 further including means for generating a radio frequency (RF) signal, means for modulating said RF signal with said encoded data signal, and means for periodically transmitting said modulated RF signal to a location remote from said tag.

9. The tag as set forth in claim 8 wherein said tamper sensing means includes means for sensing whether said enclosed housing is being held near the skin of the individual wearing said tag.

10. The tag as set forth in claim 9 further including strap means for holding said enclosed housing near the skin of the individual wearing said tag, and wherein said tamper sensing means further includes means for sensing whether said strap means has been broken or cut.

11. A method of signaling a tamper condition in a tag adapted to be worn by an individual being monitored by an electronic monitoring system, said tag including circuit means for detecting any attempt to remove the tag from the individual, and means for generating and transmitting a status signal to a location remote from said tag, said method comprising the steps of:

(a) generating within said tag a digital multi-bit code word that uniquely identifies said particular tag;

(b) generating within said tag a digital tamper signal having at least one bit in response to said detecting means detecting an attempt to remove the tag from the individual;

(c) combining said multi-bit code word and said tamper signal in an encoded data signal, said encoded data signal having at least one bit representative of said tamper signal, and a plurality of bits representative of said multi-bit code word; and

(d) transmitting said encoded data signal as said status signal to a location remote from said tag;

whereby an examination of said at least one bit of said encoded data signal at a location remote from said tag provides an indication as to whether any attempt has been made to remove the tag identified by the plurality of bits representative of said multi-bit code word from the individual wearing said tag.