Location data validation by static entities receiving location data items by short-range communication

• US 20020163901A1
• Filed: 01/23/2002
• Published: 11/07/2002
• Est. Priority Date: 01/31/2001
• Status: Active Grant

• Current Assignee: HTC Corporation
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Spratt, Michael P.
• Granted Patent: US 7,027,820 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: G01S 1/045 Receivers
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A static but movable device has a short-range wireless transceiver by which it can receive location data items. These items are usable by a location-data processing arrangement of the device to derive an estimate of the current location of the device. If the device is moved to another location, this estimate will cease to be valid. Accordingly, the device is provided with a move detection arrangement for detecting indications that the device may have been moved, these indications being used by a location-validity supervisor to determine whether or not the current location estimate is to be treated as still valid.

Claims

1. A static but movable device comprising:

a short-range wireless receiver;

a location-data processing arrangement for deriving an estimate of the current location of the device on the basis of location data received by the short-range receiver;

a move detection arrangement for detecting indications that the device at least may have been moved, and

a location-validity supervisor for determining, following detection of one or more indications by the move detection arrangement, whether the current location estimate is to be treated as still valid.

2. A device according to claim 1, wherein the move detection arrangement comprises an arrangement for detecting a said indication in the form of an indication that the device has been powered down and then powered back up.

3. A device according to claim 1, wherein the move detection arrangement comprises an motion detector for detecting a said indication in the form of an indication of physical motion of the device.

4. A device according to claim 1, wherein the device includes a network interface for connecting the device to a LAN, the move detection arrangement comprising an arrangement for detecting a said indication in the form of a change in address of the part of the LAN to which the device is connected via the network interface.

5. A device according to claim 1, wherein the move detection arrangement comprises an arrangement for detecting a said indication in the form of a change in the set of nearby devices from which the subject device can receive transmissions via its short-range receiver.

6. A device according to claim 1, wherein the move detection arrangement comprises an arrangement for detecting a said indication in the form of an inconsistency between newly received location data and one or both of the current location estimate and previously-received location data.

7. A device according to claim 1, wherein the move detection arrangement comprises at least two of the following:

an arrangement for detecting a said indication in the form of an indication that the device has been powered down and then powered back up;

a motion detector for detecting a said indication in the form of an indication of physical motion of the device;

an arrangement for detecting a said indication in the form of a change in address of the part of the LAN to which the device is connected via a network interface of the device;

an arrangement for detecting a said indication in the form of a change in the set of nearby devices from which the subject device can receive transmissions via its short-range receiver;

an arrangement for detecting a said indication in the form of an inconsistency between newly received location data and one or both of the current location estimate and previously-received location data.

8. A device according to claim 1, wherein the location-validity supervisor is operative to determine that the current location estimate is invalid upon detection of one said indication by the move detection arrangement.

9. A device according to claim 1, wherein the move detection arrangement is operative to detect at least two different types of indications, the location-validity supervisor being operative to determine that the current location estimate is invalid upon detection of a predetermined combination of indications of two or more types by the move detection arrangement.

10. A device according to claim 9, wherein the move detection arrangement comprises both a first detector arrangement for detecting a first said indication in the form of an indication that the device has been powered down and then powered back up, and a second detector arrangement for detecting a second said indication constituted by a change in the set of nearby devices from which the subject device can receive transmissions via its short-range receiver;

the location-validity supervisor being responsive to the detection of a said first indication to query the second detector arrangement as to whether said second indication is present, the location-validity supervisor determining the current location estimate to be invalid when both said first and second indications are present.

11. A device according to claim 9, wherein the move detection arrangement comprises both a first detector arrangement for detecting a first said indication in the form of an indication that the device has physically been subject to motion, and a second detector arrangement for detecting a second said indication constituted by a change in the set of nearby devices from which the subject device can receive transmissions via its short-range receiver;

the location-validity supervisor being responsive to the detection of a said first indication to query the second detector arrangement as to whether said second indication is present, the location-validity supervisor determining the current location estimate to be invalid when both said first and second indications are present.

12. A device according to claim 1, wherein the location-validity supervisor is operative to determine that the current location estimate is invalid upon detection of multiple occurrences of one type of indication.

13. A device according to claim 12, wherein the move detection arrangement comprises a consistency-check arrangement for detecting a said indication in the form of an inconsistency between newly received location data and one or both of the current location estimate and previously-received location data, the location-validity supervisor being operative to determine that the current location estimate is invalid upon detection of multiple occurrences of a said indication by the consistency-check arrangement.

15. A method according to claim 14, wherein step (b) involves detecting at least one of the following types of indication:

an indication that the device has been powered down and then powered back up;

an indication of physical motion of the device;

an indication in the form of a change in address of the part of the LAN to which the device is connected via a network interface of the device;

an indication in the form of a change in the set of nearby devices from which the subject device can receive transmissions via its short-range receiver;

an indication in the form of an inconsistency between newly received location data and one or both of the current location estimate and previously-received location data.

17. A device according to claim 16, wherein the watch means comprises at least one of:

means for detecting power down/power up of the device;

means for detecting a significant discrepancy between the most recently received location data and previously received location data;

a displacement sensor.

14. A method of providing a validity-checked location estimate for a static, but movable, device, the method comprising the steps of:

(a)—

deriving an estimate of the current location of the device on the basis of location data received by a short-range receiver of the device;

(b)—

detecting indications that the device at least may have been moved, and

(c)—

determining, following detection of one or more indications by the move detection arrangement, whether the current location estimate is to be treated as still valid.

16. A static but movable device comprising location means for receiving location data passed to it from nearby devices and for deriving a best estimate of its own location from the received location data, and watch means for watching for an indication that the device has been, or may have been moved, and for causing the location means to discard its previously-obtained location data and location estimate.