Methods and systems for noise removal in indoor positioning

• US 10,001,543 B1
• Filed: 02/01/2017
• Issued: 06/19/2018
• Est. Priority Date: 02/01/2017
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Abadi, Aharon, Melamed, Roie, Shapira, Natalie
• Primary Examiner(s): Cai, Wayne H
• Application Number:
  US15/421,446
• Time in Patent Office: 503 Days
• CPC Class Codes: G01S 5/017 Detecting state or type of motion
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A computerized method of improving position measurement of an indoor positioning system (IPS), comprising: gathering a plurality of position samples of a mobile device measured by an indoor wireless device, each of the position samples is indicative of a measured position and a measurement time; estimating a movement direction of the mobile device from the plurality of position samples; receiving a current position sample of the mobile device; estimating a temp movement direction of the mobile device from at least one of the plurality of position samples and the current position sample; and when the temp movement direction is identified as false, marking the current position sample as noise.

Claims

1. A computerized method of improving position measurement of an indoor positioning system (IPS), comprising:

gathering a plurality of position samples of a mobile device measured by an indoor wireless device, each of said position samples is indicative of a measured position and a measurement time;

estimating a movement direction of said mobile device from said plurality of position samples;

receiving a current position sample of said mobile device;

estimating a movement velocity of said mobile device from said plurality of position samples and said current position sample;

when said movement velocity is higher than a predetermined maximal velocity, marking said current position sample as noise;

estimating a temp movement direction of said mobile device from at least one of said plurality of position samples and said current position sample; and

when said temp movement direction is identified as false, marking said current position sample as noise.

2. The method of claim 1, wherein said estimating a temp movement direction is based on two latest of said plurality of position samples.

3. The method of claim 1, wherein said at least one of said plurality of position samples is a latest of said plurality of position samples.

4. The method of claim 1, wherein said indoor wireless device is a Wi-Fi access point device.

5. The method of claim 1, further comprising:

calculating a direction difference between said temp movement direction to said movement direction; and

when said direction difference is small, identifying said temp movement direction as true and updating said movement direction to be said temp movement direction.

6. The method of claim 1, further comprising when said direction difference is large:

receiving a next position sample of said mobile device;

estimating a next temp movement direction of said mobile device from at least one of said plurality of position samples and said next position sample; and

calculating a new direction difference between said temp new movement direction to said movement direction; and

when said new direction difference is small, identifying said temp movement direction as false.

7. The method of claim 1, further comprising:

calculating a time difference between a measurement time of a latest of said plurality of position samples and a measurement time of said current position sample;

when said time difference is longer than a predetermined maximal difference, updating said movement direction to be said temp movement direction.

8. The method of claim 1, further comprising:

when said movement velocity is lower than a predetermined maximal velocity, adding said current position sample to said dataset.

9. The method of claim 1, wherein said estimating is based on an inaccuracy radius of said indoor wireless device.

10. The method of claim 1, wherein said maximal velocity is determined based on an average walking speed of a person.

11. The method of claim 1, wherein said current position sample marked as noise is added to a noise history list.

12. A non-transitory computer readable medium comprising computer executable instructions adapted to perform the method of claim 1.

13. A system of improving position measurement of an indoor positioning system (IPS), comprising:

an indoor wireless device for measuring a plurality of position samples of a mobile device, each of said position samples is indicative of a measured position and a measurement time;

a dataset for storing said plurality of position samples; and

a processor for;

estimating a movement direction of said mobile device from said plurality of position samples;

estimating a temp movement direction of said mobile device from at least one of said plurality of position samples and a current position sample of said mobile device;

when said temp movement direction is identified as false, marking said current position sample as noise;

estimating a movement velocity of said mobile device from said plurality of position samples and said current position sample; and

when said movement velocity is higher than a predetermined maximal velocity, marking said current position sample as noise.

14. A software program product for improving position measurement of an indoor positioning system (IPS), comprising:

a non-transitory computer readable storage medium;

a dataset for storing a plurality of position samples of a mobile device measured by an indoor wireless device, each of said position samples is indicative of a measured position and a measurement time;

first program instructions for estimating a movement direction of said mobile device from said plurality of position samples;

second program instructions for receiving a current position sample of said mobile device;

third program instructions for estimating a temp movement direction of said mobile device from at least one of said plurality of position samples and said current position sample;

fourth program instructions for marking said current position sample as noise when said temp movement direction is identified as false;

fifth program instructions for estimating a movement velocity of said mobile device from said plurality of position samples and said current position sample;

sixth program instructions for marking said current position sample as noise when said movement velocity is higher than a predetermined maximal velocity; and

wherein said first, second, third fourth, fifth, and sixth program instructions are executed by at least one computerized processor from said non-transitory computer readable storage medium.