Relative positioning

Patent metadata

Field	Value
Publication number	US-2025020756-A1
Application number	US-202118713874-A
Country	US
Kind code	A1
Filing date	Nov 30, 2021
Priority date	Nov 30, 2021
Publication date	Jan 16, 2025
Grant date	—

Abstract

A method and network node for relative positioning measurements of wireless device (WD) locations are disclosed. According to one aspect, a method includes phase-locking a plurality of antenna reference points (ARPs), using a synchronous clock, allowing an accuracy of spatial coordinate estimates to be reduced while increasing their precision. The method includes determining time difference of arrival values based at least in part on applying weights to signals received from antennas of a subset of the plurality of phase-locked ARPs to further increase a precision of the spatial coordinate estimates. The method also includes estimating the spatial coordinates by applying timing error corrections to the time difference of arrival values to increase accuracy of the spatial coordinate estimates while maintaining the precision of the spatial coordinate estimates above the second precision level.

First claim

1 . A method in a network node for estimating spatial coordinates of a wireless device, WD, to achieve a relative positioning accuracy, the method comprising:
phase-locking a plurality of antenna reference points, ARPs, using a synchronous clock, the phase-locking configured to allow an accuracy of spatial coordinate estimates to be reduced from a first accuracy level to a second accuracy level while increasing a precision of the spatial coordinate estimates above a first precision level; determining time difference of arrival values based at least in part on applying weights to signals received from antennas of a subset of the plurality of phase-locked ARPs, the weights and phase-locked ARPs in the subset of phase-locked ARPs being determined to increase a precision of the spatial coordinate estimates above a second precision level higher than the first precision level; and estimating the spatial coordinates by applying timing error corrections to the time difference of arrival values, the applied timing error corrections being determined to increase accuracy of the spatial coordinate estimates above the second accuracy level, while maintaining the precision of the spatial coordinate estimates above the second precision level.

2 . The method of claim 1 , wherein the applied timing error corrections are based at least in part on over-the-air timing measurements.

3 . The method of claim 1 , wherein determining the time difference of arrival values includes:
selecting one ARP in the subset of the plurality of phase-locked ARPs to be a reference ARP; and correlating a signal from the reference ARP with signals from other ARPs in the subset of the plurality of phase-locked ARPs.

4 . The method of claim 3 , further comprising, prior to phase-locking the plurality of ARPs, obtaining a coarse phase alignment of the plurality of ARPs using a precision time protocol, PTP.

5 . The method of claim 1 , further comprising choosing ARPs to be in the subset of the plurality of phase-locked ARPs based at least in part on a level of multipath.

6 . The method of claim 1 , further comprising choosing ARPs to be in the subset of the plurality of phase-locked ARPs based at least in part on reducing a covariance of the spatial coordinate estimates.

7 . The method of claim 1 , wherein phase-locking the plurality of ARPs further comprises synchronizing the ARPs to a common clock reference to reduce non-common mode errors relative to common mode errors.

8 . The method of claim 1 , wherein a number of phase-locked ARPs to be included in the subset of the plurality of phase-locked ARPs is a minimum number achievable subject to at least one constraint.

9 . The method of claim 1 , wherein the applied timing error corrections are added to the time difference of arrival values.

10 . The method of claim 1 , wherein the spatial coordinate estimates are determined relative to a ubiety location selected by a user of the WD.

11 . A network node for estimating spatial coordinates of a wireless device, WD, to achieve a relative positioning accuracy, the network node comprising:
a synchronous clock; a plurality of antenna reference points, ARPs; and processing circuitry in communication with the synchronous clock and the plurality of ARPs, the processing circuitry configured to:
phase-lock the plurality of ARPs using the synchronous clock, the phase-locking configured to allow an accuracy of spatial coordinate estimates to be reduced from a first accuracy level to a second accuracy level lower than the first accuracy level while increasing a precision of the spatial coordinate estimates above a first precision level, the ARPs being spatially distributed;
determine time difference of arrival values based at least in part on applying weights to signals received from antennas of a subset of the plurality of phase-locked ARPs, the weights and phase-locked ARPs in the subset of the plurality of phase-locked ARPs being determined to increase a precision of the spatial coordinate estimates above a second precision level higher than the first precision level; and
estimate the spatial coordinates by applying timing error corrections to the time difference of arrival values, the applied timing error corrections being determined to increase accuracy of the spatial coordinate estimates above the second accuracy level, while maintaining the precision of the spatial coordinate estimates above the second precision level.

12 . The network node of claim 11 , wherein the applied timing error corrections are based at least in part on over-the-air timing measurements.

13 . The network node of claim 11 , wherein determining the time difference of arrival values includes:
selecting one ARP in the subset of the plurality of phase-locked ARPs to be a reference ARP; and correlating a signal from the reference ARP with signals from other ARPs in the subset of the plurality of phase-locked ARPs.

14 . The network node of claim 13 , wherein the processing circuitry is further configured to, prior to phase-locking the plurality of ARPs, obtain a coarse phase alignment of the plurality of ARPs using a precision time protocol, PTP.

15 . The network node of claim 11 , wherein the processing circuitry is further configured to choose ARPs to be in the subset of the plurality of phase-locked ARPs based at least in part on a level of multipath.

16 . The network node of claim 11 , wherein the processing circuitry is further configured to choose ARPs to be in the subset of the plurality of phase-locked ARPs based at least in part on reducing a covariance of the spatial coordinate estimates.

17 . The network node of claim 11 , wherein phase-locking the plurality of ARPs further comprises synchronizing the plurality of ARPs to a common clock reference to reduce non-common mode errors relative to common mode errors.

18 . The network node of claim 11 , wherein a number of phase-locked ARPs to be included in the subset of the plurality of phase-locked ARPs is a minimum number achievable subject to at least one constraint.

19 . The network node of claim 11 , wherein the applied timing error corrections are added to the time difference of arrival values.

20 . The network node of claim 11 , wherein the spatial coordinate estimates are determined relative to a ubiety location selected by a user of the WD.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Irvine Garry
• Smith Roland
• Iun Edwin

Classifications

• 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

• G01S5/0284 Primary

  Relative positioning · CPC title

• G01S5/0244 Primary

  Accuracy or reliability of position solution or of measurements contributing thereto · CPC title

• G01S5/021

  Calibration, monitoring or correction (G01S5/0252 takes precedence) · CPC title

• G01S5/0205

  Details · CPC title