Radio frequency security system with direction and distance locator

Claim 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.