INDOOR POSITIONING USING PRESSURE SENSORS

• US 20120072110A1
• Filed: 09/17/2010
• Published: 03/22/2012
• Est. Priority Date: 09/17/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Venkatraman, SaiPradeep
• Granted Patent: US 9,234,965 B2
• Time in Patent Office: Days
• US Class Current: 701/434
• CPC Class Codes: G01C 21/08 involving use of the magnetic field of the earth
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G01S 19/10 providing dedicated supplementary positioning signals
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 5/0045 Transmission from base station to mobile station G01S5/009 takes precedence
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/02585 at least one of the measurements being a non-radio measurement
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: G09B 29/00 Maps; Plans; Charts; Diagrams, e.g. route diagram star maps G09B27/04; devices for holding or supporting maps A47B97/02; for computing purposes G06G1/14, G09B1/16; display boards G09F
• CPC Class Codes: G09B 29/008 Touring maps or guides to public transport networks
• CPC Class Codes: G09B 29/10 Map spot or coordinate position indicators; Map reading aids optical projection apparatus per se G03B

Abstract

A pressure sensor can be implemented on a network device to minimize vertical positioning errors of the network device in an indoor environment. A reference altitude and a reference pressure associated with an access point in the indoor environment are received at the network device via a communication network. A pressure is determined at the network device in the indoor environment. An altitude of the network device associated with the pressure at the network device in the indoor environment is calculated based, at least in part, on the pressure at the network device, the reference pressure, and the reference altitude. A position of the network device in the indoor environment is determined based, at least in part, on the altitude of the navigation device and location information received from at least the access point.

Claims

1. A method for position estimation in an indoor environment, the method comprising:

receiving, at a wireless network device via a communication network, a reference altitude and a reference pressure associated with the reference altitude from an access point in the indoor environment;

determining a pressure at the wireless network device in the indoor environment;

calculating an altitude of the wireless network device associated with the pressure at the wireless network device in the indoor environment based, at least in part, on the pressure at the wireless network device, the reference pressure, and the reference altitude; and

determining a position of the wireless network device in the indoor environment based, at least in part, on the altitude of the wireless network device and location information received from at least the access point.

2. The method of claim 1, where said determining the position of the wireless network device in the indoor environment based, at least in part, on the altitude of the wireless network device and the location information received from at least the access point comprises determining the position of the wireless network device based, at least in part, on the altitude of the wireless network device and the location information received from the access point and from one or more additional access points in the indoor environment, wherein the communication network comprises at least the wireless network device, the access point, and the one or more additional access points.

3. The method of claim 1, further comprising:

determining routing directions to a destination based on a horizontal position of the wireless network device and the altitude of the wireless network device, wherein the position of the wireless network device corresponds to the horizontal position of the wireless network device and the altitude of the wireless network device; and

presenting the routing directions to the destination on the wireless network device.

4. The method of claim 1, further comprising:

identifying a map associated with the indoor environment based, at least in part, on the altitude and a horizontal position of the wireless network device; and

presenting, on the wireless network device, the identified map associated with the indoor environment.

5. The method of claim 1, further comprising:

monitoring the pressure at the wireless network device in the indoor environment;

detecting a variation in the pressure at the wireless network device in the indoor environment;

determining a new pressure at the wireless network device in the indoor environment; and

calculating a new altitude of the wireless network device in the indoor environment that corresponds to the new pressure at the wireless network device.

6. The method of claim 5, further comprising:

updating routing directions to a destination based, at least in part, on the new altitude of the wireless network device that corresponds to the new pressure;

determining whether a map associated with the indoor environment is available based, at least in part, on the new altitude of the wireless network device; and

presenting the map associated with the new altitude of the wireless network device on the wireless network device in response to determining that the map associated with the indoor environment based, at least in part, on the new altitude of the wireless network device is available.

7. The method of claim 5, wherein said calculating the new altitude of the wireless network device in the indoor environment that corresponds to the new pressure at the wireless network device further comprises one of:

transmitting, to the access point, a request for a new reference altitude and a new reference pressure corresponding to the new reference altitude in response to said detecting the variation in the pressure at the wireless network device; and

calculating the new altitude of the wireless network device based, at least in part, on the new pressure at the wireless network device, the new reference pressure, and the new reference altitude, and

calculating the new altitude of the wireless network device based, at least in part, on the new pressure at the wireless network device, the reference altitude, and the reference pressure.

8. The method of claim 1, wherein said determining the position of the wireless network device in the indoor environment based, at least in part, on the altitude of the wireless network device and location information received from at least the access point further comprises:

determining a plurality of location measurements based on navigation signals received from a plurality of navigation satellites;

calculating a measurement error associated with each of the plurality of location measurements; and

identifying a first of the plurality of location measurements with a smallest measurement error as a horizontal position of the wireless network device in the indoor environment.

9. A method for position estimation in a communication system, the method comprising:

receiving, at a first network device of the communication system, a request for reference information from a second network device of the communication system to enable positioning of the second network device in an indoor environment;

determining a reference pressure at the first network device, wherein the reference information comprises the reference pressure;

determining a reference location of the first network device, wherein the reference information comprises the reference location; and

providing the reference pressure at the first network device and the reference location of the first network device to the second wireless network device to enable the second network device to determine a position associated with the second network device in the indoor environment.

10. The method of claim 9, wherein the first network device is an access point and wherein said determining the reference location of the first network device further comprises:

determining a plurality of location measurements based on navigation signals received from a plurality of navigation satellites;

calculating a measurement error associated with each of the plurality of location measurements;

identifying a first of the plurality of location measurements with a smallest measurement error; and

storing the first of the plurality of location measurements as the reference location of the first network device.

11. The method of claim 9, wherein the first network device is a centralized location server that communicates with a plurality of access points and,

wherein said receiving the request for reference information from the second network device of the communication system further comprises determining whether the centralized location server is collocated with the plurality of access points;

and

wherein said providing the reference pressure at the first network device and the reference location at the first network device to the second wireless network device further comprises;

transmitting at least an altitude of the centralized location server and a pressure at the centralized location server if it is determined that the centralized location server is collocated with the plurality of access points; and

transmitting at least an altitude of a first of the plurality of access points and a pressure at the first of the plurality of access points, received from the first of the plurality of access points, if it is determined that the centralized location server is not collocated with the plurality of access points.

12. A communication network device comprising:

a processor;

a network interface coupled with the processor, the network interface operable to receive, via a communication network, a reference altitude and a reference pressure associated with the reference altitude from an access point in an indoor environment;

a pressure sensing unit operable to determine a pressure at the communication network device in the indoor environment; and

a location calculation unit operable to;

calculate an altitude of the communication network device associated with the pressure at the communication network device in the indoor environment based, at least in part, on the pressure at the communication network device, the reference pressure, and the reference altitude; and

determine a position of the communication network device in the indoor environment based, at least in part, on the altitude of the communication network device and location information received from at least the access point.

13. The communication network device of claim 12, wherein the location calculation unit operable to determine the position of the communication network device in the indoor environment based, at least in part, on the altitude of the communication network device and the location information received from at least the access point comprises the location calculation unit operable to:

determine the position of the communication network device based, at least in part, on the altitude of the communication network device and the location information received from the access point and one or more additional access points in the indoor environment, wherein the communication network comprises at least the communication network device, the access point, and the one or more additional access points.

14. The communication network device of claim 12, further comprising a routing unit operable to:

determine routing directions to a destination based on a horizontal position of the communication network device and the altitude of the communication network device, wherein the position of the communication network device corresponds to the horizontal position of the communication network device and the altitude of the communication network device; and

present the routing directions to the destination on the communication network device.

15. The communication network device of claim 12, further comprising a routing unit operable to:

identify a map associated with the indoor environment based, at least in part, on the altitude and a horizontal position of the communication network device; and

present, on the communication network device, the identified map associated with the indoor environment.

16. The communication network device of claim 12, further comprising:

the pressure sensing unit operable to;

monitor the pressure at the communication network device in the indoor environment;

detect a variation in the pressure at the communication network device in the indoor environment;

determine a new pressure at the communication network device in the indoor environment; and

the location calculation unit operable to;

calculate a new altitude of the communication network device in the indoor environment that corresponds to the new pressure at the communication network device.

17. The communication network device of claim 16, wherein the location calculation unit operable to calculate the new altitude of the communication network device in the indoor environment that corresponds to the new pressure at the communication network device further comprises one of the location calculation unit operable to:

transmit, to the access point, a request for a new reference altitude and a new reference pressure corresponding to the new reference altitude in response to the pressure sensing unit detecting the variation in the pressure at the communication network device; and

calculate the new altitude of the communication network device based, at least in part, on the new pressure at the communication network device, the new reference pressure, and the new reference altitude, and

calculate the new altitude of the communication network device based, at least in part, on the new pressure at the communication network device, the reference altitude, and the reference pressure.

18. One or more machine-readable storage media, having instructions stored therein, which, when executed by one or more processors causes the one or more processors to perform operations that comprise:

determining a reference altitude and a reference pressure associated with an access point in an indoor environment, wherein the reference pressure is associated with the reference altitude associated with the access point;

determining a pressure at a communication network device in the indoor environment;

calculating an altitude of the communication network device associated with the pressure at the communication network device in the indoor environment based, at least in part, on the pressure at the communication network device, the reference pressure, and the reference altitude; and

determining a position of the communication network device in the indoor environment based, at least in part, on the altitude of the communication network device and location information received from at least the access point.

19. The machine-readable storage media of claim 18, where said operation of determining the position of the communication network device in the indoor environment based, at least in part, on the altitude of the communication network device and the location information received from at least the access point comprises:

determining the position of the communication network device based, at least in part, on the altitude of the communication network device and the location information received from the access point and one or more additional access points in the indoor environment.

20. The machine-readable storage media of claim 18, wherein the operations further comprise:

determining routing directions to a destination based on a horizontal position of the communication network device and the altitude of the communication network device, wherein the position of the communication network device corresponds to the horizontal position of the communication network device and the altitude of the communication network device;

present the routing directions to the destination on the communication network device.

21. The machine-readable storage media of claim 18, wherein the operations further comprise:

identifying a map associated with the indoor environment based, at least in part, on the altitude and a horizontal position of the communication network device; and

presenting, on the communication network device, the identified map associated with the indoor environment.

22. The machine-readable storage media of claim 18, wherein the operations further comprise:

monitoring the pressure at the communication network device in the indoor environment;

detecting a variation in the pressure at the communication network device in the indoor environment;

determining a new pressure at the communication network device in the indoor environment;

calculating a new altitude of the communication network device in the indoor environment that corresponds to the new pressure at the communication network device.