Precise positioning using time of arrival with pseudo-synchronized anchor nodes

• US 10,015,632 B2
• Filed: 09/06/2017
• Issued: 07/03/2018
• Est. Priority Date: 09/09/2016
• Status: Active Grant

• Current Assignee: IHP GmbH Innovations for High Performance Microelectronics
• Original Assignee: IHP GmbH-Innovations For High Performance Microelectronics/Leibniz-Institut Fur Innovative Mikroelektronik
• Inventors: Sark, Vladica, Grass, Eckhard, Gutierrez Teran, Jesus
• Primary Examiner(s): Ajayi, Joel
• Application Number:
  US15/696,506
• Publication Number:
  US 20180132064A1
• Time in Patent Office: 300 Days
• Field of Search: 4554565
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 5/009 Transmission of differential positioning data to mobile
• CPC Class Codes: G01S 5/0226 Transmitters
• 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: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

A method of determining a position of at least one transceiver node comprises, anchor node by anchor node, transmitting respective positioning frames suitable for reception by a transceiver node and by the other anchor nodes. The transceiver node receives the positioning frames transmitted by the anchor nodes and ascertains respective times of reception for each. A solver stage determines the coordinates (x_s, y_s, z_s) of the respective transceiver node and the time t_s of transmission of the first positioning frame by an anchor node of first rank in the positioning sequence by numerically solving a non-linear system of at least five equations.

Claims

1. A method of determining a position of at least one transceiver node with respect to an at least two-dimensional coordinate space, the method comprising:

providing, at respective known spatial positions, at least four anchor nodes;

in performing a positioning sequence, anchor node by anchor node transmitting respective positioning frames suitable for reception by the at least one transceiver node and by at least one other of the anchor nodes, wherein the positioning sequence comprises

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the at least one transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame, and

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (T_Fi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame;

the at least one transceiver node receiving the positioning frames transmitted by the anchor nodes and ascertaining respective times of reception for each of the received positioning frames;

providing to a solver stage for numerically solving a non-linear system of equations the following parameters;

sets of coordinates of the known positions of the anchor nodes performing the positioning sequence,

a set of times of flight (t_tof(i-1)i) between pairs of respective anchor nodes of neighboring ranks ((i−

1) and i) in the positioning sequence, using their known positions and a known propagation speed of the positioning frames,

the respective times of reception of the respective positioning frames at the respective anchor nodes performing the positioning sequence,

the respective forwarding time spans (TFi) ascertained by the respective anchor nodes performing the positioning sequence, and

the respective times of reception of the respective positioning frames from the anchor nodes at the at least one transceiver node;

performing the solver stage, using the provided parameters, for determining the coordinates (x_s, y_s, z_s) of the respective transceiver node and the time t_s of transmission of the first positioning frame by the anchor node of first rank in the positioning sequence by numerically solving a non-linear system of at least five equations, at least four equations of the nonlinear system using the relation

2. The method of claim 1, comprising

determining a position of the at least one transceiver node with respect to a three-dimensional coordinate space, by

the solver stage solving a non-linear system of at least five equations, wherein

four equations of the nonlinear system are based on the relation

3. The method of claim 1, comprising:

determining a position of the at least one transceiver node with respect to a three-dimensional coordinate space, by;

at least five anchor nodes performing the positioning sequence, and

performing the solver stage, using the provided parameters, for determining the coordinates (x_s, y_s, z_s) of the respective transceiver node and the time is of transmission of the first positioning frame by the anchor node of first rank in the positioning sequence by numerically solving a non-linear system of at least five equations, each equation using the relation

4. The method of claim 1, wherein the anchor nodes perform the positioning sequence as follows:

the anchor nodes of first rank transmitting a first positioning frame;

in response to receiving the first positioning frame, the anchor node of second rank

measuring a time of reception of the first positioning frame,

transmitting a second positioning frame, and

ascertaining a first forwarding time span between the time of reception of the first positioning frame and the time of transmitting the second positioning frame;

in response to receiving the second positioning frame, the anchor node of third rank

measuring a time of reception of the second positioning frame,

transmitting a third positioning frame, and

ascertaining a second forwarding time span between receiving the second positioning frame and transmitting the third positioning frame; and

anchor nodes of following rank in the positioning sequence continuing this positioning sequence anchor node by anchor node until a predetermined number of at least four anchor nodes have transmitted and received respective positioning frames and ascertained their respective forwarding time span.

5. The method of claim 1, wherein the anchor nodes follow a round-robin algorithm in scheduling the positioning sequence.

6. The method of claim 1, wherein the anchor node of first rank determines the start of the positioning sequence.

7. The method of claim 1, further comprising:

the at least one transceiver node performing the solver stage for determining its respective position.

8. The method of claim 1, wherein at least one of the anchor nodes or a master node performs the second solver stage.

9. A transceiver node comprising

a transceiver positioning unit for determining spatial coordinates indicative of a position of the transceiver node with respect to an at least two-dimensional coordinate space, the transceiver positioning unit comprising:

a positioning receiver configured to receive positioning frames transmitted by anchor nodes in performing a positioning sequence involving a plurality of anchor nodes and to ascertain respective times of reception for each of the received positioning frames, the positioning sequence comprising,

anchor node by anchor node, transmitting respective positioning frames suitable for reception by the transceiver node and by at least one other of the anchor nodes, and

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame,

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (TFi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame;

the transceiver positioning unit further comprising

a solver engine for numerically solving a non-linear system of equations, the solver engine being configured to receive the following parameters;

sets of coordinates of the known positions of the anchor nodes performing positioning sequence, the positioning sequence comprising,

a set of times of flight (t_tof(i-1)i) between pairs of respective anchor nodes of neighboring ranks ((i−

1) and i) in the positioning sequence, using their known positions and a known propagation speed of the positioning frames,

the respective times of reception of the respective positioning frames at the respective anchor nodes performing the positioning sequence,

the respective forwarding time spans (T_Fi) ascertained by the respective anchor nodes performing the positioning sequence, and

the respective times of reception of the respective positioning frames from the anchor nodes at the transceiver node;

wherein the solver engine is configured, using the provided parameters, to determine coordinates (x_s, y_s, z_s) of the transceiver node and the time is of transmission of the first positioning frame by the anchor node of first rank in the positioning sequence by numerically solving a non-linear system of at least five equations, at least four equations of the nonlinear system using the relation

10. An anchor node for use in determining a position of at least one external transceiver node with respect to an at least two-dimensional coordinate space, the anchor node comprising:

a positioning anchor transceiver configured to receive and transmit positioning frames in exchange with external anchor nodes in performing a positioning sequence involving a plurality of anchor nodes, the positioning sequence comprising

anchor node by anchor node, transmitting respective positioning frames suitable for reception by the transceiver node and by at least one other of the anchor nodes, and

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame,

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (TFi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame;

wherein

the positioning anchor transceiver further configured to provide to an external solver engine for numerically solving a non-linear system of equations the following parameters ascertained in performing the positioning sequence;

the time of reception of the respective positioning frame transmitted by an external anchor node preceding in rank in the positioning sequence,

the ascertained forwarding time span (T_Fi);

wherein the anchor node further comprises

a second solver engine for numerically solving a non-linear system of equations, the second solver engine being configured to receive the following parameters;

the determined time is of transmission of the first positioning frame by the anchor node of first rank in the positioning sequence;

the sets of coordinates of the known positions of the external anchor nodes performing the positioning sequence,

the respective times of reception of the broadcast positioning frame at the respective other external anchor nodes;

wherein

the second solver engine is configured, using the provided parameters, to determine the coordinates (x_s, y_s, z_s) of the transceiver node and the time t_ST of transmission of the broadcast positioning frame by the at least one transceiver node, by numerically solving a second non-linear system of at least five equations for 3D localization, or at least four equations for 2D localization, of the nonlinear system using the relation

11. A positioning arrangement for determining a position of at least one transceiver node with respect to an at least two-dimensional coordinate space, the arrangement comprising at least four anchor nodes, wherein at least four anchor nodes are configured to jointly perform a positioning sequence comprising

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the at least one transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame,

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (T_Fi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame,

wherein the anchor nodes are for use in determining a position of at least one external transceiver node with respect to an at least two-dimensional coordinate space, the anchor node comprising:

a positioning anchor transceiver configured to receive and transmit positioning frames in exchange with external anchor nodes in performing a positioning sequence involving a plurality of anchor nodes, the positioning sequence comprising

anchor node by anchor node, transmitting respective positioning frames suitable for reception by the transceiver node and by at least one other of the anchor nodes, and

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame,

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (TFi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame;

wherein

the positioning anchor transceiver further configured to provide to an external solver engine for numerically solving a non-linear system of equations the following parameters ascertained in performing the positioning sequence;

the time of reception of the respective positioning frame transmitted by an external anchor node preceding in rank in the positioning sequence,

the ascertained forwarding time span (T_Fi);

wherein the anchor node further comprises

a second solver engine for numerically solving a non-linear system of equations, the second solver engine being configured to receive the following parameters;

the determined time is of transmission of the first positioning frame by the anchor node of first rank in the positioning sequence;

the sets of coordinates of the known positions of the external anchor nodes performing the positioning sequence,

the respective times of reception of the broadcast positioning frame at the respective other external anchor nodes;

wherein

the second solver engine is configured, using the provided parameters, to determine the coordinates (x_s, y_s, z_s) of the transceiver node and the time t_ST of transmission of the broadcast positioning frame by the at least one transceiver node, by numerically solving a second non-linear system of at least five equations for 3D localization, or at least four equations for 2D localization, of the nonlinear system using the relation

12. A positioning arrangement for determining a position of at least one transceiver node with respect to an at least two-dimensional coordinate space, the arrangement comprising at least four anchor nodes, wherein at least four anchor nodes are configured to jointly perform a positioning sequence comprising

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the at least one transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame,

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (T_Fi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame, further comprising at least one transceiver node comprising

a transceiver positioning unit for determining spatial coordinates indicative of a position of the transceiver node with respect to an at least two-dimensional coordinate space, the transceiver positioning unit comprising:

a positioning receiver configured to receive positioning frames transmitted by anchor nodes in performing a positioning sequence involving a plurality of anchor nodes and to ascertain respective times of reception for each of the received positioning frames, the positioning sequence comprising,

anchor node by anchor node, transmitting respective positioning frames suitable for reception by the transceiver node and by at least one other of the anchor nodes, and

a given anchor node transmitting a respective positioning frame for reception by at least that anchor node, which is the next anchor node in the positioning sequence, and by the transceiver node,

the next anchor node in the positioning sequence receiving the positioning frame from that anchor node, which is the preceding anchor node in the positioning sequence, and ascertaining a time of reception of the positioning frame,

the next anchor node ascertaining, after transmitting its respective positioning frame, a respective forwarding time span (TFi) between the time of reception of the positioning frame from the preceding anchor node and the time of transmitting the its respective positioning frame;

the transceiver positioning unit further comprising

a solver engine for numerically solving a non-linear system of equations, the solver engine being configured to receive the following parameters;

sets of coordinates of the known positions of the anchor nodes performing positioning sequence, the positioning sequence comprising,

a set of times of flight (t_tof(i-1)i) between pairs of respective anchor nodes of neighboring ranks ((i−

1) and i) in the positioning sequence, using their known positions and a known propagation speed of the positioning frames,

the respective times of reception of the respective positioning frames at the respective anchor nodes performing the positioning sequence,

the respective forwarding time spans (T_Fi) ascertained by the respective anchor nodes performing the positioning sequence, and

the respective times of reception of the respective positioning frames from the anchor nodes at the transceiver node;

wherein the solver engine is configured, using the provided parameters, to determine coordinates (x_s, y_s, z_s) of the transceiver node and the time is of transmission of the first positioning frame by the anchor node of first rank in the positioning sequence by numerically solving a non-linear system of at least five equations, at least four equations of the nonlinear system using the relation