Step-based positioning

Patent metadata

Field	Value
Publication number	US-12474169-B2
Application number	US-202218269863-A
Country	US
Kind code	B2
Filing date	Jan 20, 2022
Priority date	Jan 20, 2021
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

In a positioning system ( 100 ) for estimating the position of a mobile device ( 7 ), a processing system ( 9 ) receives external-range data, representative of a range between the mobile device and an external unit ( 2, 3, 4, 5 ), and acceleration data representative of acceleration of the mobile device due to its movement as it is carried by a person ( 6 ). The acceleration data is processed in a step-detection algorithm to determine step-distance data representative of a time series of step-data-based distances travelled by the mobile device, and step-distance data is processed to determine a step-data-based position estimate for the mobile device. A position estimate for the mobile device is determined by solving an optimisation problem comprising a first cost term based on distance to positions located at said range from the external unit, and a second cost term based on distance to the step-data-based position estimate or to positions located at a step-data-based distance from said step-data-based position estimate.

First claim

The invention claimed is:

1 . A method of estimating a position of a mobile device, the method comprising:
receiving external-range data representative of a range between the mobile device and an external unit, wherein the external-range data is determined using a signal travelling between the external unit and the mobile device; receiving acceleration data, determined from an accelerometer of the mobile device, wherein the acceleration data is representative of acceleration of the mobile device due to a movement of the mobile device as it is carried by a person; processing the acceleration data in a step-detection algorithm to determine step-distance data representative of a time series of step-data-based distances travelled by the mobile device as carried by the person; processing the step-distance data to determine a step-data-based position estimate for the mobile device; determining a position estimate for the mobile device by solving an optimisation problem for an objective function comprising a first cost term that depends on distance to positions located at said range from the external unit, and a second cost term that depends on distance to said step-data-based position estimate or to positions located at a step-data-based distance from said step-data-based position estimate; and controlling or applying a weighting of the second cost term relative to the first cost term for solving the optimisation problem.

2 . The method of claim 1 , wherein the second cost term depends on distance to positions located at a step-data-based distance from said step-data-based position estimate, and wherein the step-data-based distance is determined from one or more preceding step-data-based position estimates.

3 . The method of claim 2 , wherein the second cost term is weighted in the objective function at least in part in dependence on a variance of the step-data-based distance over time.

4 . The method of claim 1 , wherein the second cost term depends on distance to said step-data-based position estimate, and wherein the second cost term is equal or proportional to a Mahalanobis distance to the step-data-based position estimate.

5 . The method of claim 1 , wherein determining the step-data-based position estimate comprises processing an initial position estimate, determined from an earlier solving of the optimisation problem, to update the initial position estimate based on the time series of step-data-based distances.

6 . The method of claim 1 , comprising combining heading data for the mobile device with the step-distance data to determine a motion vector or series of motion vectors, and using the motion vector or series of motion vectors to determine the step-data-based position estimate.

7 . The method of claim 1 , wherein the acceleration data comprises a time series of acceleration values, and wherein processing the acceleration data in the step-detection algorithm to determine the step-distance data comprises fitting a periodic function to the time series of acceleration values to determine a characteristic frequency representative of a step frequency of a person carrying the mobile device.

8 . The method of claim 1 , wherein the external-range data is determined from timing information for the signal travelling between the external unit and the mobile device.

9 . The method of claim 1 , wherein the acceleration data comprises a time series having a first update frequency, and the external-range data comprises a time series having a second update frequency, and wherein the first update frequency is higher than the second update frequency.

10 . The method of claim 1 , wherein the first cost term is an increasing function of distance between the position estimate to be determined and positions located at said range from the external unit.

11 . The method of claim 1 , wherein the objective function comprises a plurality of cost terms, each depending on distance to respective positions located at a respective range from a respective external unit of a plurality of external units configured to exchange respective signals with the mobile device.

12 . The method of claim 1 , wherein the second cost term is an increasing function of distance between the position estimate to be determined and said step-data-based position estimate, or positions located at a step-data-based distance from said step-data-based position estimate.

13 . The method of claim 1 , wherein each cost term is a continuously differentiable function of distance, and the objective function comprises a linear combination of the first and second cost terms.

14 . The method of claim 1 , wherein the second cost term is weighted relative to the first cost term in the optimisation problem in dependence on a variable weight parameter.

15 . A positioning system for estimating a position of a mobile device, the positioning system comprising a processing system, wherein the processing system comprises a processor and is configured to:
receive external-range data representative of a range between the mobile device and an external unit, wherein the external-range data is determined using a signal travelling between the external unit and the mobile device; receive acceleration data, determined from an accelerometer of the mobile device, wherein the acceleration data is representative of acceleration of the mobile device due to a movement of the mobile device as the mobile device is carried by a person; process the acceleration data in a step-detection algorithm to determine step-distance data representative of a time series of step-data-based distances travelled by the mobile device as carried by the person; process the step-distance data to determine a step-data-based position estimate for the mobile device; determine a position estimate for the mobile device by solving an optimisation problem for an objective function comprising a first cost term that depends on distance to positions located at said range from the external unit, and a second cost term that depends on distance to said step-data-based position estimate or to positions located at a step-data-based distance from said step-data-based position estimate; and control or apply a weighting of the second cost term relative to the first cost term for solving the optimisation problem.

16 . A non-transitory computer-readable storage medium storing instructions for estimating a position of a mobile device, which, when executed on a processing system comprising a processor, cause the processing system to:
receive external-range data representative of a range between the mobile device and an external unit, wherein the external-range data is determined using a signal travelling between the external unit and the mobile device; receive acceleration data, determined from an accelerometer of the mobile device, wherein the acceleration data is representative of acceleration of the mobile device due to a movement of the mobile device as the mobile device is carried by a person; process the acceleration data in a step-detection algorithm to determine step-distance data representative of a time series of step-data-based distances travelled by the mobile device as carried by the person; process the step-distance data to determine a step-data-based position estimate for the mobile device; determine a position estimate for the mobile device by solving an optimisation problem for an objective function comprising a first cost term that depends on distance to positions located at said range from the external unit, and a second cost term that depends on distance to said step-data

Assignees

• Sonitor Technologies As

Inventors

• Thio Vincent Martello Kwie Hoe
• Booij Wilfred Edwin

Classifications

• G01S5/30

  Determining absolute distances from a plurality of spaced points of known location · CPC title

• G01C22/006

  Pedometers · CPC title

• G01C21/1652 Primary

  with ranging devices, e.g. LIDAR or RADAR · CPC title