Method and system for providing enhanced location based information for wireless handsets using dead reckoning

• US 9,258,675 B2
• Filed: 06/10/2015
• Issued: 02/09/2016
• Est. Priority Date: 08/18/2011
• Status: Active Grant

• Current Assignee: Rivada Networks, LLC
• Original Assignee: Rivada Research, Llc (Rivada Networks, LLC)
• Inventors: Surampudi, Pumima, Aguilar, Cesar Alfonso, Caceres, Alan Joseph J., Smith, Clint
• Primary Examiner(s): LE, NHAN T
• Application Number:
  US14/735,210
• Publication Number:
  US 20150281884A1
• Time in Patent Office: 244 Days
• Field of Search: 455/404.1, 455/404.2, 455/414.1, 455/414.2, 4554561-4566, 455517-519, 455/418, 455/422.1
• US Class Current: 1/1
• CPC Class Codes: G01C 17/02 Magnetic compasses
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/0072 Transmission between mobile stations, e.g. anti-collision systems
• CPC Class Codes: G01S 5/0264 at least one of the systems being a non-radio wave positioning system
• CPC Class Codes: G01S 5/0284 Relative positioning
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering
• CPC Class Codes: H04M 1/72421 with automatic activation of emergency service functions, e.g. upon sensing an alarm
• CPC Class Codes: H04M 1/72457 according to geographic location
• CPC Class Codes: H04M 2250/10 including a GPS signal receiver
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• 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 4/025 using location based information parameters
• CPC Class Codes: H04W 4/026 using orientation information, e.g. compass
• 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 4/08 User group management
• CPC Class Codes: H04W 4/90 : Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 64/006 : with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Methods, devices and systems for generating enhanced location information on or about a mobile device may include improved dead reckoning solutions in which the mobile device performs location determination calculations with the aid of network components or global positioning systems (GPS). The network aided location information may be provided to the processor and utilized in measuring the accuracy of sensor based location calculations. The mobile device may utilize local sensors to obtain a set of combined sensor output location information, which may seed execution of dead reckoning. To ensure that most accurate location information is provide to the enhanced location based service, the dead reckoning location information may be compared to a current best estimate. Results of the comparison may be passed to the enhanced location based service and the methods, systems, and devices may reiterate the location determination.

Claims

1. A method of providing an enhanced location based service via a mobile device, comprising:

receiving, in a processor of the mobile device via an antenna of the mobile device, a first set of externally determined location information and a second set of externally determined location information from one or more external location tracking systems;

generating by the processor a best stride length estimate based on the first set of externally determined location information, the second set of externally determined location information and output of an accelerometer of the mobile device;

generating, by the processor, a best altitude estimate based on output of a barometer of the mobile device, and at least one of the first set of externally determined location information and the second set of externally determined location information;

generating, by the processor, a best compass heading estimate based on output of a magnetometer of the mobile device, output of the accelerometer of the mobile device, and at least one of the first set of externally determined location information and the second set of externally determined location information;

generating, by the processor, dead reckoning location information based on the best stride length estimate, the best altitude estimate, and the best compass heading estimate;

calculating, by the processor, a best location estimate based on the dead reckoning location information and a set of externally determined location information; and

using the best location estimate to provide a location based service in the mobile device.

2. The method of claim 1, wherein receiving the first set of externally determined location information comprises receiving location information that includes a longitude value, a latitude value, a declination value, and an altitude value.

3. The method of claim 1, wherein the operations of receiving the first set of externally determined location information and the second set of externally determined location information from the one or more external location tracking systems are performed repeatedly until the location based service terminates.

4. The method of claim 1, wherein generating the best stride length estimate further comprises:

calculating a distance between the first set of externally determined location information and the second set of externally determined location information;

adding the calculated distance to a distance sum;

determining whether a number of distances calculated exceeds a pre-determined threshold and continuing calculating distances until the number of distances calculated exceeds the pre-determined threshold;

calculating an average stride length;

determining whether an error associated with the average stride length is within a pre-determined stride error threshold; and

updating a stored best stride length estimate to the average stride length in response to determining that the error associated with the average stride length falls within a pre-determined stride length error threshold.

5. The method of claim 4, wherein calculating the distance between the first set of externally determined location information and the second set of externally determined location information and adding the calculated distance to the distance sum further comprises executing a haversine function on the first set of externally determined location information and the second set of externally determined location information.

6. The method of claim 1, wherein generating the best altitude estimate comprises:

calculating an altitude estimate from the output of the barometer;

calculating a moving average altitude;

determining whether an error associated with the moving average altitude is within a pre-determined altitude error threshold; and

updating a stored best altitude estimate to the moving average altitude in response to determining that the error associated with the moving average altitude is within the pre-determined altitude error threshold.

7. The method of claim 6, further comprising:

performing kalman filter operations on the output of the barometer to remove observation noise and produce a filtered sensor output.

8. The method of claim 6, further comprising:

determining a difference between the altitude estimate and an altitude component of at least one of the first set of externally determined location information or the second set of externally determined location information to produce a bias value; and

updating an altitude sum to include the difference between the altitude estimate and an altitude component of the first or second location information normalized by the bias value.

9. The method of claim 6, further comprising:

increasing a frequency of barometer readings in response to determining that the error associated with the moving average altitude does not fall within the pre-determined altitude error threshold.

10. The method of claim 1, wherein generating a best heading estimate comprises:

generating rotation information based on the output of the accelerometer and the output of the magnetometer; and

adjusting the rotation information to an offset of true north to produce the best compass heading estimate.

11. The method of claim 10, wherein generating the rotation information comprises performing kalman filter operations on the output of the accelerometer and the output of the magnetometer to produce the rotation information.

12. The method of claim 10, wherein updating the rotation information to the offset of true north further comprises:

comparing the rotation information to declination information associated with at least one of the first set of externally determined location information or the second set of externally determined location information.

13. The method of claim 1, wherein determining the best location estimate comprises:

determining whether a distance between the first or second set of externally determined location information and the dead reckoning location information is below a pre-determined comparison threshold;

calculating a midpoint between the set of externally determined location information and the dead reckoning location information in response to determining that the distance between externally determined location information and the dead reckoning location information is less than the pre-determined comparison threshold; and

updating the best location estimate to the midpoint.

14. The method of claim 1, wherein the one or more external location tracking systems comprise a global positioning (GPS) or service provider.

15. A mobile computing device, comprising:

an antenna;

an accelerometer;

a barometer;

a magnetometer; and

a processor coupled to the antenna, the accelerometer, the barometer, and the magnetometer, wherein the processor is configured with processor executable instructions to perform operations comprising;

receiving a first set of externally determined location information and a second set of externally determined location information from one or more external location tracking systems;

generating a best stride length estimate based on the first set of externally determined location information, the second set of externally determined location information, and output of the accelerometer;

generating a best altitude estimate based on output of the barometer and at least one of the first set of externally determined location information and the second set of externally determined location information;

generating a best compass heading estimate based on output of the magnetometer, output of the accelerometer, and at least one of the first set of externally determined location information and the second set of externally determined location information;

generating dead reckoning location information based on the best stride length estimate, the best altitude estimate, and the best compass heading estimate;

calculating a best location estimate based on the dead reckoning location information and a set of externally determined location information; and

using the best location estimate to provide a location based service.

16. The mobile computing device of claim 15, wherein the processor is configured with processor executable instructions to perform operations such that generating the best stride length estimate comprises:

calculating a distance between the first set of externally determined location information and the second set of externally determined location information to generate a result, and adding the result to a distance sum;

determining whether a number of distances calculated exceeds a pre-determined threshold and continuing calculating distances until the number of distances calculated exceeds the pre-determined threshold;

calculating an average stride length;

determining whether an error associated with the average stride length is within a pre-determined stride error threshold; and

updating a stored best stride length estimate to the average stride length in response to determining that the error associated with the average stride length falls within a pre-determined stride length error threshold.

17. The mobile computing device of claim 15, wherein the processor is configured with processor executable instructions to perform operations such that generating the best altitude estimate comprises:

calculating an altitude estimate from the output of the barometer;

calculating a moving average altitude;

determining whether an error associated with the moving average altitude is within a pre-determined altitude error threshold; and

updating a stored best altitude estimate to the moving average altitude in response to determining that the error associated with the moving average altitude is within the pre-determined altitude error threshold.

18. A non-transitory computer readable storage medium having stored thereon processor-executable software instructions configured to cause a processor of a mobile device to perform operations comprising:

receiving a first set of externally determined location information and a second set of externally determined location information from one or more external location tracking systems;

generating a best stride length estimate based on the first set of externally determined location information, the second set of externally determined location information and output of an accelerometer of the mobile device;

generating a best altitude estimate based on output of a barometer of the mobile device, and at least one of the first set of externally determined location information and the second set of externally determined location information;

generating a best compass heading estimate based on output of a magnetometer of the mobile device, output of the accelerometer of the mobile device, and at least one of the first set of externally determined location information and the second set of externally determined location information;

generating dead reckoning location information based on the best stride length estimate, the best altitude estimate, and the best compass heading estimate;

calculating a best location estimate based on the dead reckoning location information and a set of externally determined location information; and

using the best location estimate to provide a location based service.

19. The non-transitory computer readable storage medium of claim 18, wherein the stored processor-executable software instructions are configured to cause a processor to perform operations such that generating the best stride length estimate comprises:

calculating a distance between the first set of externally determined location information and the second set of externally determined location information to generate a result, and adding the result to a distance sum;

determining whether a number of distances calculated exceeds a pre-determined threshold and continuing calculating distances until the number of distances calculated exceeds the pre-determined threshold;

calculating, by the processor, an average stride length;

determining whether an error associated with the average stride length is within a pre-determined stride error threshold; and

updating a stored best stride length estimate to the average stride length in response to determining that the error associated with the average stride length falls within a pre-determined stride length error threshold.

20. The non-transitory computer readable storage medium of claim 18, wherein the stored processor-executable software instructions are configured to cause a processor to perform operations such that generating the best altitude estimate comprises:

calculating an altitude estimate from the output of the barometer;

calculating a moving average altitude;

determining whether an error associated with the moving average altitude is within a pre-determined altitude error threshold; and

updating a stored best altitude estimate to the moving average altitude in response to determining that the error associated with the moving average altitude is within the pre-determined altitude error threshold.