Locating and authentication system

• US 5,493,283 A
• Filed: 11/14/1994
• Issued: 02/20/1996
• Est. Priority Date: 09/28/1990
• Status: Expired due to Fees

• Current Assignee: Olivetti Solutions S.p.A.
• Original Assignee: Olivetti Research Ltd. (AT&T, Inc.)
• Inventors: Want, Roy, Hopper, Andrew, Wheeler, David J., Needham, Roger M.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US08/339,643
• Time in Patent Office: 463 Days
• Field of Search: 340/825.34, 340/825.44, 340/825.54, 340/825.55, 340/825.49, 340/825.31, 340/825.69, 340/825.72, 379/55, 379/62, 379/92, 379/201, 379/210, 379/211, 379/196, 455/58, 380/23, 380/25
• US Class Current: 340/5.8
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

A system for locating any mobile body of a plurality thereof within a predetermined environment, wherein each mobile body carries a transmitter (10 to 18), each transmitter producing a unique identifying signal, and a plurality of receivers (20 to 32) located in a corresponding plurality of defined regions in the environment, each receiver incorporating a FIFO buffer memory (28) into which carrier identifying data is inserted and a controller for interrogating the receiver means in turn to link the identification data with location data. (FIG. 1 ). A carrier authentication system is also described.

Claims

1. An authentication system for verifying the identity of a mobile carder comprising a static base station comprising:

a processor unit for generating a random number;

memory means for storing said random number and a plurality of identification numbers; and

an infra-red PPM transmitter for transmitting said random number in the form of a PPM signal;

wherein said mobile carrier comprises;

an infra-red PPM signal detector for detecting said PPM signal when said mobile carrier is within the vicinity of said static base station;

a signal amplifier connected to said infra-red PPM signal detector for amplifying said PPM signal;

a PPM signal decoder connected to said signal amplifier for decoding said PPM signal in the form of said random number;

a first latch for receiving said random number;

a memory wherein is stored a predetermined secret password;

a first encryption table connected to said memory and to said latch for generating a first encrypted number in response to said predetermined secret password and to said random number;

a second encryption table connected to said first encryption table for generating a second encrypted number in response to said first encrypted number;

a second latch for receiving said second encrypted number;

a PPM encoder connected to said second latch for combining said second encryption number with an identification number of said mobile carder and for generating a corresponding serial number in the form of an identification signal;

a buffer amplifier connected to said PPM encoder for amplifying said identification signal; and

an infra-red PPM signal transmitter connected to said buffer amplifier for transmitting said identification signal to said static base station, said buffer amplifier being connected also to said signal,amplifier for inhibiting said signal amplifier whilst said infra-red PPM signal transmitter is transmitting said identification signal;

wherein said static base station further comprises;

an infra-red PPM detector for detecting said identification signal from said mobile carrier;

a look-up table wherein all the enabled secret passwords are stored;

a first and a second static encryption tables, having the same configuration of said first and second encryption tables of said mobile carrier, for generating a response signal in response of said random number and of a corresponding secret password stored in said look-up table; and

comparison means for comparing said identification signal received from said mobile carrier with said response signal and generating a consequent authentication signal,

said comparison means generates said authentication signal solely when said identification signal and said response signal are identical.

2. An authentication system as claimed in claim 1, wherein said PPM signal decoder comprises validating means for validating said PPM signal amplified by said signal amplifier.

3. An authentication system as claimed in claim 1, wherein said random number is in the form of a 16-bit parallel data word supplied as input address to said first static encryption table and to said first encryption table of said mobile carder and wherein the output from said second static encryption table and from said second encryption table of said mobile carder is a 16-bit parallel data word scrambled version of said random number and of the selected secret password.

4. An authentication system as claimed in claim 1, wherein said mobile carrier comprises a badge.

5. An authentication system for verifying the identity of a badge and/or the user of said badge comprising a static base station comprising:

a processor unit for generating a random number;

memory means for storing said random number and a plurality of identification numbers; and

an infra-red PPM transmitter for transmitting said random number in the form of a PPM signal;

wherein said badge comprises;

an infra-red PPM signal detector for detecting said PPM signal when said badge is within the vicinity of said static base station;

a signal amplifier connected to said infra-red PPM signal detector for amplifying said PPM signal;

a PPM signal decoder connected to said signal amplifier for decoding said PPM signal in the form of said random number, said decoder comprising validating means for validating said PPM signal amplified by said signal amplifier;

a first latch for receiving said random number;

a memory wherein is stored a predetermined secret password;

a first encryption table connected to said memory and to said latch for generating a first encrypted number in response to said predetermined secret password and to said random number;

a second encryption table connected to said first encryption table for generating a second encrypted number in response to said first encrypted number;

a second latch for receiving said second encrypted number;

a PPM encoder connected to said second latch for combining said second encryption number with an identification number of said badge and for generating a corresponding serial number in the form of an identification signal;

a buffer amplifier connected to said PPM encoder for amplifying said identification signal; and

an infra-red PPM signal transmitter connected to said buffer amplifier for transmitting said identification signal to said static base station, said buffer amplifier being connected also to said signal amplifier for inhibiting said signal amplifier whilst said infra-red PPM signal transmitter is transmitting said identification signal;

wherein said static base station further comprises;

an infra-red PPM detector for detecting said identification signal from said badge;

a look-up table wherein all the enabled secret passwords are stored;

a first and a second static encryption tables, having the same configuration of said first and second encryption tables of said badge, for generating a response signal in response of said random number and of a corresponding secret password stored in said look-up table; and

comparison means for comparing said identification signal received from said

badge with said response signal and generating a consistent authentication signal, said comparison means generates said authentication signal solely when said identification signal and said response signal are identical.

6. A system as claimed in claim 5, wherein said random number is in the form of a 16-bit parallel data word supplied as input address to said first, static encryption table and to said first encryption table of said badge and wherein the output from said second static encryption table and from said second encryption table of said mobile carder is a 16-bit parallel data word scrambled version of said random number and of the selected secret password.