Radio frequency security system with direction and distance locator

• US 5,714,932 A
• Filed: 02/27/1996
• Issued: 02/03/1998
• Est. Priority Date: 02/27/1996
• Status: Expired due to Fees

• Current Assignee: Radtronics, Inc.
• Original Assignee: Radtronics, Inc.
• Inventors: Recio, Adrian Dario, Barrios, Mario Aldo, Castellon, Roberto J.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Pope, Daryl C.
• Application Number:
  US08/606,736
• Time in Patent Office: 707 Days
• Field of Search: 340/539, 340/573, 340/571, 340/572, 340/691, 340/825.04, 340/825.06, 455/67.1, 455/67.7, 342/419, 342/417, 342/450, 342/385, 342/386
• US Class Current: 340/539.11
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• CPC Class Codes: G08B 21/0247 System arrangements wherein the alarm criteria uses signal strength
• CPC Class Codes: G08B 21/0263 System arrangements wherein the object is to detect the direction in which child or item is located
• CPC Class Codes: G08B 21/0286 Tampering or removal detection of the child unit from child or article

Abstract

The radio frequency (RF) security system includes a central control unit and a plurality of portable transmitters (up to 128 transmitters) which are in radio frequency communication with the central control unit. This communication is one-way from the portable transmitters to the central control unit. The central control unit and the portable transmitters both include microprocessors and associated memory. Each portable transmitter is assigned a unique unit binary code. In order to detect destruction of the transmitter unit, a powerline is imbedded in an elongated band which is placed on the wrist of a child or attached to an inanimate object. When the band is severed, the powerline is severed and the microprocessor in the portable transmitter is shut down. During normal operation (without the band being severed), the portable transmitter has an RF transmitting circuit which is fed the unique unit code and which frequency modulates (FM) the RF carrier signal with the unit code. The resulting FM signal is transmitted to the central control unit. When power is severed to the microprocessor, the RF transmitter in the portable transmitter continuous emitting an RF carrier signal. The central control unit, in addition to the microprocessor and memory, includes a keypad input device, an antenna system, an RF directional detection circuit, a threshold detection circuit, an identification circuit, distance measuring circuit, and several displays. One display shows the orientation or bearing as well as the distance between the central control unit and each portable transmitter unit. This is accomplished by the directional detection circuit generating phase differential signals which are analyzed by the microprocessor in order to determine the relative position and a distance measuring circuit which determines distance by the relative strength of the received RF signal. The threshold detection circuit determines when the received RF signal fails below a certain threshold. At that time, the threshold detection circuit issues an alarm which stops the scan cycle of the microprocessor. Upon issuance of an alarm, the unique unit code is displayed to the operator so that the operator can easily determine which transmitter has been severed or which transmitter has left the security region (approximately 1,000 feet).

Claims

1. A radio frequency (RF) security system with a direction and distance locator comprising:

a central control unit;

said central control unit including a power output port;

a plurality of portable transmitters in radio frequency communication with said central control unit, each portable transmitter unit having a unique unit code assigned thereto, and each portable transmitter unit including;

a microcontroller supplied with the respective unit code for said portable transmitter unit and having means for generating an RF control signal representative of said respective unit code;

a power supply electrically coupled to said microcontroller via a power line;

an elongated band with a lockable latch mechanism, said band carrying said power line thereon such that upon severance of said band, said powerline is similarly severed;

a modulatable RF transmitting circuit, including an antenna, being coupled to said microcontroller and being modulated by said RF control signal, said transmitting circuit generating a modulated RF signal based upon said RF control signal and generating an RF carrier signal in the absence of said RF control signal, said transmitting circuit being coupled to said power supply independent from said power line carried by said band;

said central control unit including;

a microprocessor coupled to a memory, said memory storing all unit codes therein, said microprocessor generating unit code commands representative of said unit codes;

a keypad input device, coupled to said microprocessor, for inputting unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving said modulated RF signal from each transmitter unit and generating a received modulated RF signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon the corresponding received modulated RF signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received modulated RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a threshold detection circuit, coupled to said antenna system and said microprocessor, said threshold detection circuit receiving said received modulated RF signal and determining when that signal falls below a predetermined signal strength level and generating an alarm command;

a decoder circuit, coupled to said microprocessor and said antenna system, said decoder circuit decoding receiving said received modulated RF signal, extracting said unit code therefrom and comparing the extracted unit code to said unit code command received from said microprocessor, said decoder circuit including means for generating a unit code display command representing said unit code;

a second display, coupled to said decoder circuit, for displaying an image representing said unit code based upon said unit code display command; and

said microprocessor having means for generating unit code commands for all transmitter units such that said RF directional detection circuit and said threshold detection circuit scans for all RF modulated signals based upon said unit codes stored in said memory;

said RF security system further including;

a portable search and locate unit, said portable locate unit including;

a power input port complementary to said power output port on said central control unit;

a microprocessor coupled to a memory, said memory storing one or more tracking unit codes therein, said tracking unit codes representing unit codes for portable transmitter units subject to a search and locate mission, said microprocessor generating corresponding unit code commands representative of said tracking unit codes;

a keypad input device, coupled to said microprocessor, for inputting said tracking unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving said modulated RF signal from each transmitter unit and generating a received modulated RF signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon the corresponding received modulated RF signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received modulated RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a second display, coupled to said microprocessor, for displaying an image representing said unit code based upon said tracking unit code command; and

said microprocessor having means for generating tracking unit code commands for all transmitter units subject to said search and locate mission such that said RF directional detection circuit scans for all RF modulated signals based upon said tracking unit codes stored in said memory.

2. A security system with a direction and distance locator as claimed in claim 1 wherein said microprocessor includes means for cycling through all unit codes stored in said memory and including means for stopping said cycling means upon receipt of said alarm command.

3. A radio frequency (RF) security system with a direction and distance locator comprising:

a central control unit;

a plurality of portable transmitters in radio frequency communication with said central control unit, each portable transmitter unit having a unique unit code assigned thereto, and each portable transmitter unit including;

a microcontroller supplied with the respective unit code for said portable transmitter unit and having means for generating an RF control signal representative of said respective unit code;

a power supply electrically coupled to said microcontroller via a power line;

an elongated band with a lockable latch mechanism, said band carrying said power line thereon such that upon severance of said band, said power line is similarly severed;

a modulatable RF transmitting circuit, including an antenna, being coupled to said microcontroller and being modulated by said RF control signal, said transmitting circuit generating a modulated RF signal based upon said RF control signal and generating an RF carrier signal in the absence of said RF control signal, said transmitting circuit being coupled to said power supply independent from said power line carried by said band;

said central control unit including;

a microprocessor coupled to a memory, said memory storing all unit codes therein, said microprocessor generating unit code commands representative of said unit codes;

a keypad input device, coupled to said microprocessor, for inputting unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving one of said modulated RF signal and said RF carrier signal from each transmitter unit and respectively generating a received modulated RF signal and a received RF carrier signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon the corresponding received modulated RF signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received modulated RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a threshold detection circuit, coupled to said antenna system and said microprocessor, said threshold detection circuit receiving said received modulated RF signal and determining when that signal fails below a predetermined signal strength level and generating an alarm command, in a first instance, and generating said alarm signal when said threshold detection circuit receives said received RF carrier signal in a second instance;

a decoder circuit, coupled to said microprocessor and said antenna system, said decoder circuit, in said first instance, decoding receiving said received modulated RF signal, extracting said unit code therefrom and comparing the extracted unit code to said unit code command received from said microprocessor, said decoder circuit including means for generating a unit code display command representing said unit code, and said decoder circuit, in said second instance, receiving said unit code command from said microprocessor and said means for generating said unit code display command;

a second display, coupled to said decoder circuit, for displaying an image representing said unit code based upon said unit code display command; and

said microprocessor having means for generating unit code commands for all transmitter units such that said RF directional detection circuit and said threshold detection circuit scans for all RF modulated signals based upon said unit codes stored in said memory and having means for cycling through all unit codes stored in said memory and including means for stopping said cycling means upon receipt of said alarm command.

4. A security system with a direction and distance locator as claimed in claim 3 including an amplifier, for enhancing the display commands and said first display.

5. A security system with a direction and distance locator as claimed in claim 4 including an alarm system coupled to said threshold detection circuit, said alarm system comprising at least one of an audio alarm and a visual alarm.

6. A security system with a direction and distance locator as claimed in claim 5 including electrical ports coupled to said alarm system, said ports adopted to output said alarm command to an external alarm system electrically coupled to said security system via said ports.

7. A security system with a direction and distance locator as claimed in claim 3 including means for resetting said cycling means subsequent to stopping the scan cycle with said means for stopping.

8. A security system with a direction and distance locator as claimed in claim 3 wherein said central control unit includes a power output port;

said RF security system including;

a portable search and locate unit, said portable locate unit including;

a power input port complementary to said power output port on said central control unit;

a microprocessor coupled to a memory, said memory storing one or more tracking unit codes therein, said tracking unit codes representing unit codes for portable transmitter units subject to a search and locate mission, said microprocessor generating corresponding unit code commands representative of said tracking unit codes;

a keypad input device, coupled to said microprocessor, for inputting said tracking unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving said modulated RF signal from each transmitter unit and generating a received modulated RF signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon the corresponding received modulated RF signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received modulated RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a second display, coupled to said microprocessor, for displaying an image representing said unit code based upon said tracking unit code command; and

said microprocessor having means for generating tracking unit code commands for all transmitter units subject to said search and locate mission such that said RF directional detection circuit scans for all RF modulated signals based upon said tracking unit codes stored in said memory.

9. A security system with a direction and distance locator as claimed in claim 3 wherein said central control unit includes a power output port;

said RF security system including;

a portable search and locate unit, said portable locate unit including;

a power input port complementary to said power output port on said central control unit;

a microprocessor coupled to a memory, said memory storing one or more tracking unit codes therein, said tracking unit codes representing unit codes for portable transmitter units subject to a search and locate mission, said microprocessor generating corresponding unit code commands representative of said tracking unit codes;

a keypad input device, coupled to said microprocessor, for inputting said tracking unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving one of said modulated RF signal and said RF carrier signal from each transmitter unit and respectively generating a received modulated RF signal and a received RF carrier signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon one of the corresponding received modulated RF signal and the received RF carrier signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a second display, coupled to said microprocessor, for displaying an image representing said unit code based upon said tracking unit code command; and

said microprocessor having means for generating tracking unit code commands for all transmitter units subject to said search and locate mission such that said RF directional detection circuit scans for all RF signals based upon said tracking unit codes stored in said memory.

10. A security system with a direction and distance locator as claimed in claim 9 including an amplifier, for enhancing said display commands and said first display.

11. A security system with a direction and distance locator as claimed in claim 8 including an amplifier, for enhancing said display commands and said first display.

12. A radio frequency (RF) security system with a direction and distance locator comprising:

a central control unit;

a plurality of portable transmitters in radio frequency communication with said central control unit, each portable transmitter unit having a unique unit code assigned thereto, and each portable transmitter unit including;

a microcontroller supplied with the respective unit code for said portable transmitter unit and having means for generating an RF control signal representative of said respective unit code;

a power supply electrically coupled to said microcontroller via a power line;

an elongated band with a lockable latch mechanism, said band carrying said power line thereon such that upon severance of said band, said power line is similarly severed;

a modulatable RF transmitting circuit, including an antenna, being coupled to said microcontroller and being modulated by said RF control signal, said transmitting circuit generating a modulated RF signal based upon said RF control signal and generating an RF carrier signal in the absence of said RF control signal, said transmitting circuit being coupled to said power supply independent from said power line carried by said band;

said central control unit including;

a microprocessor coupled to a memory, said memory storing all unit codes therein, said microprocessor generating unit code commands representative of said unit codes;

a keypad input device, coupled to said microprocessor, for inputting unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving one of said modulated RF signal and said RF carrier signal from each transmitter unit and respectively generating a received modulated RF signal and a received RF carrier signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon one of the corresponding received modulated RF signal and the received RF carrier signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a threshold detection circuit, coupled to said antenna system and said microprocessor, said threshold detection circuit receiving said received modulated RF signal and determining when that signal falls below a predetermined signal strength level and generating an alarm command, in a first instance, and generating said alarm signal when said threshold detection circuit receives said received RF carrier signal in a second instance;

a decoder circuit, coupled to said microprocessor and said antenna system, said decoder circuit, in said first instance, decoding receiving said received modulated RF signal, extracting said unit code therefrom and comparing the extracted unit code to said unit code command received from said microprocessor, said decoder circuit including means for generating a unit code display command representing said unit code, and said decoder circuit, in said second instance, receiving said unit code command from said microprocessor and said means for generating said unit code display command;

a second display, coupled to said decoder circuit, for displaying an image representing said unit code based upon said unit code display command; and

said microprocessor having means for generating unit code commands for all transmitter units such that said RF directional detection circuit and said threshold detection circuit scans for all RF signals based upon said unit codes stored in said memory and having means for cycling through all unit codes stored in said memory and including means for stopping said cycling means upon receipt of said alarm command.

13. A security system with a direction and distance locator as claimed in claim 12 including an amplifier, having a gain control actuated by an operator, or enhancing said display commands and said first display.

14. A security system with a direction and distance locator as claimed in claim 13 including an alarm system coupled to said threshold detection circuit, said alarm system comprising at least one of an audio alarm and a visual alarm.

15. A security system with a direction and distance locator as claimed in claim 14 including electrical ports coupled to said alarm system, said ports adopted to output said alarm command to an external alarm system electrically coupled to said security system via said ports.

16. A security system with a direction and distance locator as claimed in claim 12 including means for resetting said cycling means subsequent to stopping the scan cycle with said means for stopping.

17. A security system with a direction and distance locator as claimed in claim 16 wherein said central control unit includes a power output port;

said RF security system including;

a portable search and locate unit, said portable locate unit including;

a power input port complementary to said power output port on said central control unit;

a microprocessor coupled to a memory, said memory storing one or more tracking unit codes therein, said tracking unit codes representing unit codes for portable transmitter units subject to a search and locate mission, said microprocessor generating corresponding unit code commands representative of said tracking unit codes;

a keypad input device, coupled to said microprocessor, for inputting said tracking unit codes into said memory via said microprocessor;

an antenna system, including a plurality of antennas in an array, receiving one of said modulated RF signal and said RF carrier signal from each transmitter unit and respectively generating a received modulated RF signal and a received RF carrier signal representative thereof;

an RF directional detection circuit, coupled to said antenna system and said microprocessor, said directional detection circuit receiving said unit code commands from said microprocessor and having means for generating phase differential signals indicative of a corresponding spatial orientation of each transmitter unit relative to said central control unit based upon one of the corresponding received modulated RF signal and the received RF carrier signal;

said microprocessor having means for converting said phase differential signals into display commands representing the relative position and means for determining the relative strength of the received RF signal from each transmitter unit;

a first display, coupled to said microprocessor, receiving said display commands and displaying a directional and distance image for the respective portable transmitter unit;

a second display, coupled to said microprocessor, for displaying an image representing said unit code based upon said tracking unit code command; and

said microprocessor having means for generating tracking unit code commands for all transmitter units subject to said search and locate mission such that said RF directional detection circuit scans for all RF signals based upon said tracking unit codes stored in said memory.

18. A security system with a direction and distance locator as claimed in claim 17 including an amplifier, having a gain control actuated by an operator, coupled intermediate said means for converting said phase differential signals into display commands and said first display such that the directional and distance image for the respective portable transmitter unit subject to said search and locate mission and showing the relative position and the relative strength of the received RF signal is magnified.