Frictionless access control system providing ultrasonic user location

Patent metadata

Field	Value
Publication number	US-11030835-B2
Application number	US-201816205806-A
Country	US
Kind code	B2
Filing date	Nov 30, 2018
Priority date	Dec 1, 2017
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A frictionless access control system and method providing ultrasonic user location are disclosed. The access control system authorizes users within proximity of an access point such as a door, based upon user information (e.g. credentials) sent in RF wireless messages from user devices carried by the users. When the users are authorized, the system instructs the user devices to transmit coded acoustic signals. An positioning unit at the access point includes an ultrasonic microphone array, which is located above the access point and detects the acoustic signals. The positioning unit determines an angle of arrival (AoA) of the acoustic signals at microphones of the array, and determines positions of the users relative to the access point from the AoA. In one implementation, pre-authorized users are granted access when the determined positions of the users are within an inner zone of the access point.

First claim

What is claimed is:

1. An access control system for monitoring an access point, comprising:
a positioning unit for receiving acoustic signals from user devices of users, for generating position information indicating positions and directions of movement of the user devices relative to the access point based on the acoustic signals, and for generating instructions based on the position information, wherein the positioning unit includes one or more microphones installed above the access point for detecting the acoustic signals from the user devices; and
an access point controller for controlling access through the access point in response to the instructions from the positioning unit,
wherein the positioning unit comprises an audio processing and location module for determining an angle of arrival of the acoustic signals at the one or more microphones based on the acoustic signals, and the positioning unit determines that the user devices are within an inner zone of the access point based on whether the angle of arrival is sufficiently small.

2. The system of claim 1 , wherein the positioning unit includes an ultrasonic microphone array for detecting the acoustic signals from the user devices.

3. The system of claim 1 , wherein the user devices transmit the acoustic signals to the positioning unit in response to receiving wireless signals from the positioning unit.

4. The system of claim 1 , wherein the positioning unit sends wireless signals to different user devices instructing each of the different user devices to generate acoustic signals at different carrier frequencies with respect to each other.

5. The system of claim 1 , wherein the positioning unit comprises a wireless credential reader for receiving radio frequency (RF) signals from the user devices, the RF signals including user information identifying the users.

6. The system of claim 5 , wherein the positioning unit determines whether the user devices are authorized by sending the user information to a verification and authentication system via a local network and receiving authentication information returned from the verification and authentication system, the authorization information indicating whether or not the users of the user devices are authorized to pass through the access point.

7. The system of claim 6 , wherein the verification and authentication system compares the user information to that of authorized users in a verification database and/or compares tokens contained in the user information to tokens provided by a token server.

8. The system of claim 6 , wherein the positioning unit, in response to determining that the users of the user devices are authorized users and that the user devices are located within an inner zone of the access point, sends unlock signals to the access point controller, and the positioning unit, in response to determining that the users of the user devices are authorized users and that the user devices are located beyond an inner zone of the access point, does not send the unlock signals to the door controller.

9. The system of claim 6 , wherein, in response to receiving the authorization information, the positioning unit obtains movement information from the user devices, the movement information being generated via accelerometers of the user devices detecting movement and the movement information indicating whether the user devices are moving.

10. The system of claim 9 , wherein, in response to determining that the users of the user devices are authorized users and that the user devices are located beyond an inner zone of the access point but are moving closer to the access point, the positioning unit requests that the user devices repeat transmission of the acoustic signals.

11. The system of claim 1 , wherein the one or more microphones includes an ultrasonic microphone array, which comprises a plurality of microphones arranged to form the ultrasonic microphone array, and the audio processing and location module determines a time difference of arrival of the acoustic signals across the microphone array.

12. The system of claim 11 , wherein the positioning unit determines the angle of arrival based on the time difference of arrival of the acoustic signals across the microphone array by measuring a difference in phase of the acoustic signals detected at each of the one or more microphones and converting the time difference of arrival to the angle of arrival.

13. The system of claim 12 , wherein the positioning unit determines the position of the user device relative to the access point based on the angle of arrival.

14. The system of claim 13 , wherein the angle of arrival includes an elevation angle and an azimuth angle.

15. The system of claim 13 , wherein spacing between a first microphone and a second microphone of the microphone array provides a phase shift for the acoustic signals detected at the first microphone relative to the acoustic signals detected at the second microphone on the order of a quarter wavelength of the acoustic signals.

16. The system of claim 15 , wherein the wavelength of the acoustic signals is between 16-18 millimeters, and spacing between the microphones of the microphone array is 4 millimeters.

17. The system of claim 12 , wherein the microphones of the microphone array are located in a plane that is parallel to or perpendicular to a ceiling and floor above and below the access point, respectively.

18. The system of claim 1 , wherein the one or more microphones are arranged to form an ultrasonic microphone array comprising microphones which are spaced apart by at least 4 millimeters.

19. The system of claim 1 , wherein the positioning unit generates the instructions based on user information identifying the users sent received from the user devices.

20. The system of claim 1 , wherein the positioning unit instructs the access point controller to grant access through the access point in response to the positioning unit:
determining that the users are authorized based on user information identifying the users received from the user devices; and
determining that the users are located within an inner zone of the access point based on the position information.

21. The system of claim 1 , wherein the system pre-authorizes the users in response to the positioning unit determining that the users are located within an outer zone of the access point based on the position information.

22. A method for controlling an access point, comprising:
one or more microphones of a positioning unit for receiving acoustic signals from user devices of users installed above the access point detecting the acoustic signals from the user devices;
the positioning unit generating position information indicating positions and directions of movement of the user devices relative to the access point based on the acoustic signals, including an audio processing and location module of the positioning unit determining an angle of arrival of the acoustic signals at the one or more microphones based on the acoustic signals received from the user devices and the positioning unit determining that the user devices are within an inner zone of the access point based on whether the angle of arrival is sufficiently small;
the positioning unit generating instructions based on the position information; and an access point controller controlling access through the access point in response to the instructions from the positioning unit.

23. The method of claim 22 , further comprisi

Assignees

• Sensormatic Electronics Llc

Inventors

• Martin Walter A
• Mckenna John
• Boyes Derek
• Neill Terry

Classifications

• G01S5/02585

  at least one of the measurements being a non-radio measurement · CPC title

• G01S2205/01

  specially adapted for specific applications · CPC title

• G01S3/8083 Primary

  determining direction of source · CPC title

• G07C9/27

  with central registration · CPC title

• G07C9/28

  the pass enabling tracking or indicating presence · CPC title