Method and device for issuing an access authorization

• US 10,403,065 B2
• Filed: 03/13/2014
• Issued: 09/03/2019
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Original Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Inventors: Gigl, Thomas, Schultes, Gerhard
• Primary Examiner(s): Syed, Nabil H
• Application Number:
  US14/776,897
• Publication Number:
  US 20160027226A1
• Time in Patent Office: 2,000 Days
• CPC Class Codes: G07C 2009/00555 comprising means to detect or avoid relay attacks
• CPC Class Codes: G07C 2009/0096 Electronic keys comprising a non-biometric sensor
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence

Abstract

Presented are methods and devices for issuing an authorization for access to a secured area, particularly a building, a room, a vehicle, a computer system or the like, or for starting a machine, a vehicle, a computer or the like, having a monitoring unit comprising a transmitter, a receiver, and an evaluation device, and having a key, a key card or similar, referred to as a key in short below, having a transmitter, a receiver and an electronic device. A permissible position and/or a permissible distance between the transmitter of the monitoring unit and a permissible key is determined prior to issuing an authorization, wherein the transmitter of the monitoring unit transmits signals and the key transmits response signals back to the monitoring unit. The permissible position and/or the permissible distance of the key are determined from the signals received by the key, wherein a signal strength of said signals is evaluated in various directions and/or angles.

Claims

1. An access authorization system comprising:

a monitoring unit comprising;

a first transmitter to transmit a first signal at a first frequency, and

a first receiver to receive a response signal; and

a key comprising;

a second transmitter to transmit the response signal to the monitoring unit at a second frequency,

a second receiver to receive the first signal, and

an electronic device configured to determine a signal strength of the first signal in at least one direction; and

at least one of an acceleration sensor, a rotation sensor, and a gravity sensor configured to measure a gravity vector associated with an expected motion of one of the monitoring unit and the key, the gravity vector being used to correct the signal strength;

an evaluation device configured to perform a fingerprinting procedure to validate the key, the fingerprinting procedure comprises determining at least one of a distance and a relative position between the key and the monitoring unit based on the response signal.

2. The access authorization system according to claim 1, wherein the one of the first and second receiver comprises a plurality of coils.

3. The access authorization system according to claim 2, further comprising a circuit that is configured to determine a direction of permeation of a magnetic field between at least two of the plurality of coils.

4. The access authorization system according to claim 3, wherein the circuit is further configured to determine a polarization of a transmitted signal.

5. The access authorization system according to claim 3, wherein the circuit is coupled to the second receiver.

6. The access authorization system according to claim 1, further comprising a database to store calibrated data for at least one of the distance and the relative position.

7. The access authorization system according to claim 1, wherein the monitoring unit comprises a current measuring circuit that measures one or more currents.

8. The access authorization system according to claim 1, wherein the evaluation device compares a strength of the first signal with the calibrated measured current to adjust the response signal prior to performing the fingerprinting procedure.

9. A method for accessing an authorization system, the method comprising:

transmitting via a first transmitter first signal at a first frequency from a monitoring unit to a first receiver that is designed to receive a response signal;

transmitting via a second transmitter the response signal to the monitoring unit at a second frequency;

determining a signal strength of the first signal in at least one direction;

measuring a gravity vector associated with an expected motion of one of the first and the second transmitter, the gravity vector being used to correct the signal strength; and

performing a fingerprinting procedure to validate a key via an electronic device, the fingerprinting procedure comprising determining at least one of a distance and a relative position between the key and the monitoring unit based on the response signal.

10. The method according to claim 9, further comprising determining a direction of permeation of a magnetic field between at least two coils.

11. The method according to the claim 9, wherein the signal strengths of the first signal are evaluated at least by an absolute value of a magnetic field strength vector in a horizontal plane.

12. The method according to the claim 9, wherein the signal strengths of the first signal are evaluated relatively to each other in one or more directions and angles.

13. The method according to claim 9, wherein the fingerprinting procedure comprises, prior to granting access, comparing the signal strength to an expected signal strength in a permitted access area to determine a validity of the relative position.

14. The method according to claim 9, wherein determining signal strengths of the first signal comprises determining a magnetic field strength vector based on a penetration direction through one or more coils.

15. The method according to claim 9, further comprising evaluating a polarization of one of the first signals and the response signal.

16. The method according to the claim 9, wherein an expected field strength is determined from a calibration measurement.

17. The method according to the claim 9, further comprising determining the one or more currents and comparing one or more currents to one or more calibrated currents.

18. The method according to the claim 9, further comprising detecting at least two of subdivided access areas as part of the fingerprinting procedure prior to validating the key.

19. The method according to the claim 9, further comprising using a tracking procedure that tracks the key within a predetermined area of the monitoring unit and calculates a probability to evaluate a validity of a position of the key.