Method of allowing access to an electronic device

• US 20050044424A1
• Filed: 09/23/2004
• Published: 02/24/2005
• Est. Priority Date: 11/29/2000
• Status: Active Grant

• Current Assignee: Ensure Technologies Incorporated
• Original Assignee: Ensure Technologies Incorporated
• Inventors: Xydis, Thomas G.
• Granted Patent: US 7,589,614 B2
• Time in Patent Office: Days
• US Class Current: 726/4
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: H04L 63/0492 by using a location-limited connection, e.g. near-field communication or limited proximity of entities

Abstract

The subject invention provides a method of allowing access to an electronic device (218) disposed in a working space (14) by a user (16) having a remote device (212). An initial signal is transmitted from an access point (20) instructing the remote device (212) to respond after a delay period. The remote device (212) responds upon the expiration of the delay period. The access point (20) measures a period interval from the transmission of the initial signal to the detection of a response signal. A distance of the remote device (212) is determined based upon the period interval and the known positions of the access point (20) and the electronic device (218). In another embodiment, a fixed device (256) transmits locating signals detected by three access points (220, 221, 223) and the access points (220, 221, 223) measure a time differential. The position of the remote device (212) is determined based upon a time of arrival, the location of each of the access points (220, 221, 223), and the time differential. The electronic device (218) is enabled in response to the distance of the remote device (212) being within the predetermined distance range.

Claims

1. A method of allowing access to an electronic device (218) disposed in a working space (14) by a user (16) having a remote device (212) in proximity to the electronic device (218), said method comprising the steps of:

disposing the electronic device (218) at a known position in the working space (14);

disposing an access point (20) at a known position about the working space (14);

detecting the remote device (212) with the access point (20);

transmitting an initial signal from the access point (20) instructing the remote device (212) to respond after a delay period;

detecting the initial signal with the remote device (212);

transmitting a response signal from the remote device (212) upon the expiration of the delay period;

detecting the response signal with the access point (20);

measuring a period interval from the transmission of the initial signal to the detection of the response signal by the access point (20);

determining a distance of the remote device (212) from the electronic device (218) based upon the period interval and the known positions of the access point (20) and the electronic device (218);

comparing the distance to a predetermined distance range; and

enabling the electronic device (218) in response to the distance of the remote device (212) being within the predetermined distance range such that the user (16) can access the electronic device (218).

2. A method as set forth in claim 1 further comprising the step of disabling the electronic device (218) in response to the distance of the remote device (212) being outside the predetermined distance range such that the user (16) can not access the electronic device (218).

3. A method as set forth in claim 2 further comprising the step of authenticating the user (16) at the electronic device (218) after the electronic device (218) has been enabled.

4. A method as set forth in claim 3 wherein the step of authenticating the user (16) further comprises the step of transmitting a list of authorized users (16) to the electronic device (218) to allow those users (16) to access the electronic device (218).

5. A method as set forth in claim 1 wherein the step of determining the distance further comprises the step of removing the delay period from the period interval and dividing the period interval in half to determine time of flight for either one of the initial signal and the response signal.

6. A method as set forth in claim 1 wherein the step of transmitting the initial signal is further defined as transmitting the initial signal including a data sequence to be re-transmitted as the response signal.

7. A method as set forth in claim 1 wherein the step of disposing the access point (20) is further defined as disposing a plurality of access points (20) about the working space (14).

8. A method as set forth in claim 7 wherein the step of transmitting the initial signal is further defined as transmitting the initial signal from one of the plurality of access points (20).

9. A method as set forth in claim 8 further comprising the step of compiling a database (254) of known positions for the access points (20) and connecting the database (254) to a network (13).

10. A method as set forth in claim 9 further comprising the step of detecting the period interval of the transmissions of the initial signal and the response signal at each of the remaining access points (20).

11. A method as set forth in claim 10 further comprising the step of verifying the distance based upon the monitoring of the period interval by the remaining access points (20) and the known positions of the access points (20).

12. A method as set forth in claim 11 further comprising the step of updating the database (254) with the period interval detected at each of the remaining access points (20) for error correction.

13. A method as set forth in claim 9 wherein the step of disposing the electronic device (218) is further defined as disposing a plurality of electronic devices (218) in the working space (14) each having a known position stored in the database (254).

14. A method as set forth in claim 13 further comprising the step of enabling a first set of the plurality of electronic devices (218) within the predetermined distance range and disabling a second set of the plurality of electronic device (218) outside the predetermined distance range.

15. A method as set forth in claim 1 wherein the step of detecting the remote device (212) further comprises the steps of transmitting an identification signal from the remote device (212) to identify the remote device (212) to the access point (20) and detecting the identification signal with the access point (20).

16. A method of allowing access to an electronic device (218) disposed in a working space (14) by a user (16) having a remote device (212) in proximity to the electronic device (218), said method comprising the steps of:

disposing at least three access points (220, 221, 223) about the working space (14) each at a known position and each of the access points (220, 221, 223) connected to a network (13);

compiling a database (254) of known positions for each of the access points (220, 221, 223) and connecting the database (254) to the network (13);

disposing a fixed device (256) at a known position relative to the working space (14);

storing the position of the fixed device (256) in the database (254);

transmitting locating signals from the fixed device (256);

detecting the locating signals at each of the access points (220, 221, 223);

determining a time differential between the detection of the locating signal at each of the access points (220, 221, 223);

transmitting a radio frequency (RF) signal from the remote device (212);

detecting the RF signal with the access points (220, 221, 223);

measuring a time of arrival of the RF signal at each of the access points (220, 221, 223);

determining a distance of the remote device (212) based upon the time of arrival, the location of each of the access points (220, 221, 223), and the time differential;

comparing the distance to a predetermined distance range; and

enabling the electronic device (218) in response to the distance of the remote device (212) being within the predetermined distance range such that the user (16) can access the electronic device (218).

17. A method as set forth in claim 16 further comprising the step of disabling the electronic device (218) in response to the distance of the remote device (212) being outside the predetermined distance range such that the user (16) can not access the electronic device (218).

18. A method as set forth in claim 17 further comprising the step of authenticating the user (16) at the electronic device (218) after the electronic device (218) has been enabled.

19. A method as set forth in claim 18 wherein the step of authenticating the user (16) further comprises the step of transmitting a list of authorized users (16) to the electronic device (218) to allow those users (16) to access the electronic device (218).

20. A method as set forth in claim 16 further comprising the step of determining the position of the electronic device (218) in the working space (14) relative to the plurality of access points (220, 221, 223).

21. A method as set forth in claim 20 wherein the step of determining the position of the electronic device (218) further comprises the steps of fixing the position of the electronic device (218) and connecting the electronic device (218) to the network (13).

22. A method as set forth in claim 20 wherein the step of determining the position of the electronic device (218) further comprises the steps of transmitting radio frequency (RF) signals from the electronic device (218) and detecting the RF signals at each of the access points (220, 221, 223).

23. A method as set forth in claim 22 further comprising the step of updating the database (254) with the positions of the electronic device (218) in the working space (14).