Systems and methods for precise radio frequency localization of wireless nodes using time difference of arrival and decoupling in time synchronizing of the wireless nodes from ranging

Patent metadata

Field	Value
Publication number	US-11856484-B2
Application number	US-202117371963-A
Country	US
Kind code	B2
Filing date	Jul 9, 2021
Priority date	Jul 9, 2021
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

In one embodiment, an asynchronous wireless system for localization of nodes comprises a first wireless node being configured to receive a first communication from a third wireless node having an unknown location, to determine time difference of arrival (TDoA) information of the reception of the first communication between each of the first and a second wireless node, to determine TDoA ranging including a relative or absolute position of the third wireless node using the time difference of arrival information, and to synchronize the first and second wireless nodes based on a second communication with the synchronization being decoupled in time from the first communication. In another embodiment, a computer implemented method comprises receiving, with first and second wireless anchor nodes, packets from a wireless arbitrary device and performing time difference of arrival ranging upon reception of the packets between each of the first and the second wireless anchor nodes.

First claim

What is claimed is:

1. An asynchronous wireless system for localization of nodes in a wireless network architecture, comprising:
first wireless node and a second wireless nodes each:
having a known location; and
including a wireless device with one or more processing units and radio frequency circuitry for transmitting and receiving communications in the wireless network architecture; and

a third wireless node and a fifth wireless node each:
having an unknown location; and
including a wireless device with radio frequency circuitry to enable communications with the first wireless node and the second wireless node in the wireless network architecture; and

wherein the first wireless node is configured to:
receive a first communication from the third wireless node;
determine time difference of arrival of the first communication at the first wireless node and the second wireless node;
identify a relative or absolute position of the third wireless node based on the time difference of arrival;
send a second communication with a synchronization packet to the second wireless node; and
synchronize the first wireless node and the second wireless node based on the second communication to identify a time difference between a first clock of the first wireless node and a second clock of the second wireless node, the synchronization of the first wireless node and the second wireless node being independent and decoupled from the first communication; and
receive packets from the third wireless node and the fifth wireless node in parallel via a first radio frequency channel and a second radio frequency channel, the first radio frequency channel relaying signals from the third wireless node and the second radio frequency channel relaying signal from the fifth wireless node.

2. The asynchronous wireless system of claim 1 , wherein the first wireless node is configured to determine transmission and reception timestamps of the second communication, to determine channel state information of the synchronization packet to calculate a distance between the first and second wireless nodes from known locations of the first and second wireless nodes.

3. The asynchronous wireless system of claim 1 , wherein the first wireless node is further configured to:
periodically identify a position of the third wireless node with a first frequency; and
periodically synchronize the first wireless node and the second wireless node with a second frequency falling below the first frequency.

4. The asynchronous wireless system of claim 1 , wherein the first wireless node is configured to synchronize the first and second wireless node by determining absolute clock phase difference at time of synchronization and a rate of change of the absolute clock phase difference.

5. The asynchronous wireless system of claim 1 , wherein the first wireless node is further configured to synchronize the first wireless node and the second wireless node in response to receiving the first communication.

6. The asynchronous wireless system of claim 1 , further comprising:
a fourth wireless node to send an initial communication to the third wireless node.

7. The asynchronous wireless system of claim 1 , wherein the third wireless node sends an initial communication to a fourth wireless node.

8. The asynchronous wireless system of claim 1 , further comprising a controller configured to randomly assign a wireless node in the wireless network architecture as the first wireless node.

9. The asynchronous wireless system of claim 1 , further comprising a controller configured to assign a wireless node in the wireless network architecture as the first wireless node in response to quality of a communication link between the node and the second node exceeding a threshold quality.

10. The asynchronous wireless system of claim 1 , the first wireless node is configured to synchronize the first wireless node and the second wireless node in response to identifying the position of the third wireless node.

11. The asynchronous wireless system of claim 1 :
wherein the one or more processing units of the first wireless node are configured to execute instructions to receive a third communication from the fifth wireless node, to determine time difference of arrival of the fifth communication the first wireless node and the second wireless node, and to determine a position of the fifth wireless node using the time difference of arrival information.

12. The asynchronous wireless system of claim 11 , wherein the first wireless node is configured to receive packets from the third wireless node and the fifth wireless node serially.

13. The asynchronous wireless system of claim 1 , wherein the packets captured across the first and second radio frequency channels are used to build a comprehensive location map of the third and fifth wireless nodes simultaneously, wherein packets from the third and fifth wireless nodes are captured in series during a first time period and in parallel during a second time period depending on network conditions within the wireless network architecture.

14. The asynchronous wireless system of claim 1 , wherein the first wireless node or the second wireless node comprises a third party device.

15. The asynchronous wireless system of claim 1 , wherein the first wireless node transmits addressed synchronization packets to anchor nodes individually or broadcasts the synchronization packets with no addressing to all anchor nodes.

16. The asynchronous wireless system of claim 1 , wherein the first wireless node transmits a packet to the third wireless node and this packet is received by the second wireless node and used for synchronization, the packet, in combination with the second wireless node receiving packets between the first wireless node and the third wireless node, provides contention free transmission and no overhead due to synchronization being performed with an acknowledgement packet.

17. The asynchronous wireless system of claim 1 , wherein the first wireless node and the third wireless node are configured to support fine time measurement protocol and fine time measurement packets.

18. A method comprises:
at a first time period:
at a first wireless node and a second wireless node in a population of nodes, receiving a first communication from a third wireless node in the population of nodes, the third wireless node having an unknown location;
in response to receiving the first communication at the first wireless node and the second wireless node:
determining time difference of arrival of the first communication at the first wireless node and the second wireless node; and
transmitting an acknowledgement signal including a synchronization packet from the first wireless node to the third wireless node;

determining a location of the third wireless node based on the time difference of arrival information;
receiving the acknowledgement packet at the second wireless node and the third wireless node; and

during a second time period:
synchronizing the first wireless node and second wireless node based on the acknowledgement packet with the synchronization of the first and second wireless nodes being decoupled from the first communication.

19. The method of claim 18 , further comprising:
determining transmission and reception timestamps of the second communication;
determining channel state information of the synchronization packet to calculate a distance between the first and second wireless nodes from known locations of the first and second wireless nodes, wherein the

Assignees

• Zainar Inc

Inventors

• Bilstad Mark
• Ylamurto Tommi
• Seth Manu

Classifications

• H04W4/029 Primary

  Location-based management or tracking services · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04W64/00

  Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management · CPC title

• G01S5/06

  Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/12 takes precedence) · CPC title

• G01S13/765

  with exchange of information between interrogator and responder · CPC title