LOCALIZATION FOR LOW COST SENSOR NETWORK

• US 20070076638A1
• Filed: 10/05/2005
• Published: 04/05/2007
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Gonia, Patrick, Mahasenan, Arun, Kore, Vinayak
• Granted Patent: US 7,289,466 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• CPC Class Codes: G01S 1/66 Superimposing direction-indicating intelligence signals, e.g. speech, Morse
• CPC Class Codes: G01S 5/0226 Transmitters
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

Wireless devices, systems and approaches or methods having the capability of determining the location of a given wireless device. An example system includes a wireless device that generates at least one pulse as a part of an output signal, and the at least one pulse is captured by anchor devices and used, in a time of arrival approach, to determine the location of the example device. The at least one pulse may be generated during a designated portion of an otherwise normally modulated message. Another example system includes an anchor node that generates a directional output signal, the direction output signal including data indicating its direction, and the directions of output signals from plural anchor nodes when pointed at a wireless device are used to determine the location of the wireless device. Combinations of the pulse and directional antenna systems, devices used within each of these systems, and approaches associated with these systems are also included.

Claims

1. A method of determining the location of a wireless device, the method comprising:

generating a first beacon from a first anchor node having a known location, the first beacon including a series of data packets, at least a first packet of the first beacon including an indication of the source and the direction of the first beacon at the time the first data packet is generated;

generating a second beacon from a second anchor node having a known location, the second beacon including a series of data packets, at least a second packet of the second beacon including an indication of the source and the direction of the second beacon at the time the second data packet is generated;

capturing the first data packet and the second data packet with the wireless device; and

estimating the position of the wireless device with respect to the first and second anchor nodes;

wherein the first and second beacons are spatially narrow beacons.

2. The method of claim 1 wherein at least one of the first beacon and the second beacon is generated as the main lobe of an output from a phased array antenna.

3. The method of claim 1 wherein the wireless device performs the estimating step.

4. The method of claim 1 wherein the wireless device transmits data related to the first data packet and the second data packet to another node and the another node performs the estimating step.

5. The method of claim 1 further comprising:

generating a third beacon from a third anchor node having a known location, the third beacon being a spatially narrow beacon and including a series of data packets, at least a third packet of the third beacon including an indication of the direction of the third beacon at the time the third data packet is generated;

wherein the estimating step further includes estimating the position of the wireless device with respect to the third anchor node.

6. The method of claim 5 wherein the estimating step includes using data from the third beacon to check or improve the accuracy of estimation performed using data from the first and second beacons.

7. The method of claim 5 wherein the estimating step includes estimating the location of the wireless device in three dimensions.

8. The method of claim 1 wherein the step of capturing the first data packet and the second data packet includes the following:

capturing a third data packet also generated by the first anchor node and including an indication of the source and direction of first beacon at the time the third data packet is generated;

observing the signal strength of the first beacon at the time of receipt of the first data packet and the third data packet; and

selecting the first data packet or the third data packet for use in the estimating step.

9. A wireless device including components adapted to perform wireless communication, wherein the wireless device is adapted to perform localization steps by the following steps:

receiving a first beacon from a first anchor node, the first beacon including data packets generated as part of the first beacon, at least some of the data packets indicating the source of the data packets and the direction of the first beacon at the time they are generated;

identifying a first data packet indicative of the direction of the first beacon at the time the first beacon is directed at the wireless device;

receiving a second beacon from a second anchor node, the second beacon including data packets generated as part of the second beacon, at least some of the data packets indicating the source of the data packets and the direction of the second beacon at the time they are generated; and

identifying a second data packet indicative of the direction of the second beacon at the time the second beacon is directed at the wireless device.

10. The wireless device of claim 9 wherein the localization steps further include estimating the position of the wireless device with reference to the first and second anchor nodes by the use of the first and second data packets.

11. The wireless device of claim 9 wherein the localization steps further include generating localization data including data related to the first and second data packets and sending the localization data to a localization node that performs steps for estimating the position of the wireless device.

12. The wireless device of claim 9 wherein the step of identifying the first data packet includes:

receiving the multiple data packets at different times, the multiple data packets indicating different directions of the first beacon;

comparing received signal strengths for the first beacon at times corresponding to receipt of the multiple data packets; and

selecting one of the multiple data packets that corresponds to higher received signal strength than others of the multiple data packets to be the first data packet.

13. A system adapted to communicate wirelessly, the system comprising a number of anchor nodes having known locations and at least one distributed node, the system configured to determine the location of a first distributed node by the following steps:

at least first and second anchor nodes generate first and second beacons, the first and second beacons being formed as directional beacons by the use of directional antennae, the first and second beacons being generated such that each is directed in a number of angles relative to the first and second anchor nodes, and the first and second beacons including data packets indicating the direction of the first and second beacons at the time of generation of the respective data packets;

the first distributed node captures a first data packet from the first beacon indicative of the location of the first distributed node with reference to the first anchor node when the first beacon is directed toward the first distributed node; and

the first distributed node captures a second data packet from the second beacon indicative of the location of the first distributed node with reference to the second anchor node when the second beacon is directed toward the second distributed node.

14. The system of claim 13 wherein at least one of the first and second beacons is generated by the use of a phased array antenna.

15. The system of claim 13 wherein the first distributed node determines its location with respect to the first and second anchor nodes.

16. The system of claim 13 wherein the first distributed node generates one or more messages indicating data related to the first and second data packets for sending to a localization node that determines the location of the first distributed node.

17. The system of claim 13 wherein:

a third anchor node generates a third beacon, the third beacon being formed as a directional beacon by the use of a directional antenna, the third beacon being directed in a number of angles relative the third anchor node, and the third beacon including data packets indicating the direction of the third beacon at the time of generation of the data packet; and

the first distributed node captures a third packet from the third beacon indicative of the location of the first distributed node with reference to the third anchor node when the third beacon is directed toward the first distributed node.

18. The system of claim 13 wherein at least one distributed node is adapted to generate a pulsed output in a data message, the pulsed output useful for localization by a time of arrival method, and at least one anchor node is adapted to receive a pulsed output from a distributed node and identify a time of arrival of the pulsed output.

19. The system of claim 18 wherein the system is also adapted to perform localization using a combination of directional data captured by the distributed node and time of arrival data captured by at least first and second ones of the at least one anchor node adapted to receive a pulsed output.

20. The system of claim 18 wherein a first estimation of location is made using at least one of:

a directional data method using directional data captured by a distributed node from one or more anchor nodes having directional antennae;

or

a time of arrival method using timing data captured by anchor nodes adapted to receive a pulse generated by a distributed node;

and, using the estimation of location, one of the directional data method or the time of arrival method is selected to provide a best estimate of location.

21. The system of claim 13 further comprising a new anchor node, wherein the new anchor node has a location that is determined by the use of a first method of determining location, and the new anchor node verifies its own location by capturing at least first and second directional beams from other anchor nodes.

22. A system for localization in a wireless sensor network having a plurality of wireless nodes adapted to transceive wireless signals, the network comprising:

a plurality of anchor nodes adapted to be configured with reference positional information, the anchor nodes having at least one directional antenna to broadcast positional information through at least one unidirectional wireless signal path;

a plurality of distributed nodes equipped with wireless transceivers for communication, the distributed nodes including a processor configured to capture directional and location information from at least two anchor nodes for determining the location of the sensor nodes.

23. The system of claim 22 further comprising a central processor for receiving data related to captured directional and location information from the distributed nodes and determine the location of the distributed nodes.

24. The system of claim 22 wherein the distributed nodes are adapted to determine their position with reference to the anchor nodes from captured directional and location information.