Wide area positioning system

• US 8,874,398 B2
• Filed: 09/17/2013
• Issued: 10/28/2014
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: NextNav, LLC
• Original Assignee: NextNav, LLC
• Inventors: Raghupathy, Arun, Wolf, Thomas, Meiyappan, Subramanian S
• Primary Examiner(s): Le, John H
• Application Number:
  US14/029,682
• Publication Number:
  US 20140039823A1
• Time in Patent Office: 406 Days
• Field of Search: 702/47, 702/85, 702/93, 702/94, 702/95, 702/98, 702/99, 702/116, 702/130, 702/143, 702/149, 702/150, 702/176, 702/3, 342/357.29, 342/387, 342/393, 342/462, 342/463, 342/464, 455/456.1, 455/456.6
• US Class Current: 702/94
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• 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 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 5/145 Using a supplementary range measurement, e.g. based on pseudo-range measurements

Abstract

Systems and methods for estimating a height of a mobile device are described. A reference pressure estimate is generated using atmospheric data from one or more reference locations. Various approaches for determining the reference pressure estimate are described. The reference pressure estimate is used, along with a pressure measurement at a position of a mobile device, to estimate the height of the mobile device.

Claims

1. A positioning system comprising at least one processor that:

determines a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations; and

determines an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device,

wherein the reference pressure estimate is generated based on a calculation using a first reference elevation pressure and a second reference elevation pressure, wherein the first reference elevation pressure is based on pressure and temperature measurements at a first location of a first reference sensor unit in addition to an elevation of the first reference sensor unit, and wherein the second reference elevation pressure is based on pressure and temperature measurements at a second location of a second reference sensor unit in addition to an elevation of the second reference sensor unit.

2. The positioning system of claim 1, wherein the at least one processor:

generates the reference pressure estimate based on a pressure surface gradient model.

3. The positioning system of claim 1, wherein the reference pressure estimate is generated after the first reference elevation pressure and the second reference elevation pressure are transmitted by one or more transmitters.

4. The positioning system of claim 1, wherein the at least one processor:

generates the first reference elevation pressure using the pressure and the temperature measurements at the first location of the first reference sensor unit in addition to the elevation of the first reference sensor unit; and

generates the second reference elevation pressure using the pressure and the temperature measurements at the second location of the second reference sensor unit in addition to the elevation of the second reference sensor unit.

5. The positioning system of claim 1, wherein the reference pressure estimate is generated by:

receiving, from a first reference sensor unit, a first reference elevation pressure associated with a first reference height, wherein the first reference elevation pressure is based on a first known height of the first reference sensor unit, a first pressure measured at a first location of the first reference sensor unit, and a first temperature measured at the first location;

receiving, from a second reference sensor unit, a second reference elevation pressure associated with the first reference height or a second reference height, wherein the second reference elevation pressure is based on a second known height of the second reference sensor unit, a second pressure measured at a second location of the second reference sensor unit, and a second temperature measured at the second location;

computing a first weighted reference elevation pressure based on the first reference elevation pressure and a first weight;

computing a second weighted reference elevation pressure based on the second reference elevation pressure and a second weight; and

generating the reference pressure estimate based on the first weighted reference elevation pressure and the second weighted reference elevation pressure.

6. The positioning system of claim 1, wherein the at least one processor:

determines a variation of reference elevation pressure using the reference data from each of at least two reference sensor units; and

determines the reference pressure estimate based on the variation of reference elevation pressure.

7. The positioning system of claim 1, wherein the at least one processor:

determines that the estimated elevation of the mobile device corresponds to a first floor of a building when the estimated elevation of the mobile device is within a threshold difference in elevation from a first estimated elevation of the first floor; and

determines that the estimated elevation of the mobile device corresponds to a second floor of the building when the estimated elevation of the mobile device is within the threshold difference in elevation from a second estimated elevation of the second floor.

8. A positioning system comprising at least one processor that:

determines a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determines when the position of the mobile device is approximately at a known position;

after determining that the position of the mobile device is approximately at the known position, determines an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

determines a difference between the estimated elevation and a known height of the known position.

9. The positioning system of claim 8, wherein the at least one processor:

calculates, based on the difference between the estimated elevation and the known height, a correction value associated with drift or aging related to the atmospheric sensor.

10. A positioning system comprising at least one processor that:

determines a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determines an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

determines based on satellite signals, an estimated amount of drift associated with the atmospheric sensor.

11. A positioning system comprising at least one processor that:

determines a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determines an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device;

identifies a first set of estimated elevations that are within a threshold difference in elevation from each other, wherein the first set of estimated elevations are associated with a first set of positions of one or more mobile devices; and

determines, based on the first set of estimated elevations, a first estimated elevation of a first floor in a structure.

12. The positioning system of claim 11, wherein the at least one processor:

identifies a second set of estimated elevations that are within the threshold difference in elevation from each other; and

determines, based on the second set of estimated elevations, a second estimated elevation of a second floor in the structure.

13. A positioning system comprising at least one processor that:

determines a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determines an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

calibrates the atmospheric sensor of the mobile device, wherein the atmospheric sensor is calibrated using aggregated reference data over a time period, or wherein the atmospheric sensor is calibrated when a n elevation and atmospheric pressure at the position of the mobile device is known.

14. The positioning system of claim 13, wherein the atmospheric sensor is calibrated using the aggregated reference data over the time period, wherein the at least one processor:

generates the aggregated reference data by identifying when the mobile device is at a known location; and

identifies deviations in the atmospheric data corresponding to the known location, wherein the atmospheric sensor is calibrated based on the deviations.

15. The positioning system of claim 13, wherein the atmospheric sensor is calibrated when the elevation and atmospheric pressure at the position of the mobile device is known.

16. A positioning system, wherein the system comprises:

a database that includes historical reference data of one or more reference sensor units and historical atmospheric data collected by a plurality of mobile devices; and

at least one processor that;

determines a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations; and

determines an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device.

17. A computer-implemented method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations; and

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device,

wherein the reference pressure estimate is determined based on a calculation using a first reference elevation pressure and a second reference elevation pressure, wherein the first reference elevation pressure is based on pressure and temperature measurements at a first location of a first reference sensor unit in addition to an elevation of the first reference sensor unit, and wherein the second reference elevation pressure is based on pressure and temperature measurements at a second location of a second reference sensor unit in addition to an elevation of the second reference sensor unit.

18. The computer-implemented method of claim 17, the method comprising:

generating the reference pressure estimate based on a pressure surface gradient model.

19. The computer-implemented method of claim 17, wherein the reference pressure estimate is generated after the first reference elevation pressure and the second reference elevation pressure are transmitted by one or more transmitters.

20. The computer-implemented method of claim 17, the method comprising:

generating the first reference elevation pressure using the pressure and the temperature measurements at the first location of the first reference sensor unit in addition to the elevation of the first reference sensor unit; and

generating the second reference elevation pressure using the pressure and the temperature measurements at the second location of the second reference sensor unit in addition to the elevation of the second reference sensor unit.

21. The computer-implemented method of claim 17, wherein the reference pressure estimate is generated by:

receiving, from a first reference sensor unit, a first reference elevation pressure associated with a first reference height, wherein the first reference elevation pressure is based on a first known height of the first reference sensor unit, a first pressure measured at a first location of the first reference sensor unit, and a first temperature measured at the first location;

receiving, from a second reference sensor unit, a second reference elevation pressure associated with the first reference height or a second reference height, wherein the second reference elevation pressure is based on a second known height of the second reference sensor unit, a second pressure measured at a second location of the second reference sensor unit, and a second temperature measured at the second location;

computing a first weighted reference elevation pressure based on the first reference elevation pressure and a first weight;

computing a second weighted reference elevation pressure based on the second reference elevation pressure and a second weight; and

generating the reference pressure estimate based on the first weighted reference elevation pressure and the second weighted reference elevation pressure.

22. The computer-implemented method of claim 17, the method comprising:

determining a variation of reference elevation pressure using the reference data from each of at least two reference sensor units; and

determining the reference pressure estimate based on the variation of reference elevation pressure.

23. The computer-implemented method of claim 17, the method comprising:

determining that the estimated elevation of the mobile device corresponds to a first floor of a building when the estimated elevation of the mobile device is within a threshold difference in elevation from a first estimated elevation of the first floor; and

determining that the estimated elevation of the mobile device corresponds to a second floor of the building when the estimated elevation of the mobile device is within the threshold difference in elevation from a second estimated elevation of the second floor.

24. A computer-implemented method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining when the position of the mobile device is approximately at a known position;

after determining that the position of the mobile device is approximately at the known position, determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

determining a difference between the estimated elevation and a known height of the known position.

25. The computer-implemented method of claim 24, the method comprising:

calculating, based on the difference between the estimated elevation and the known height, a correction value associated with drift or aging related to the atmospheric sensor.

26. A computer-implemented method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

determining, based on satellite signals, an estimated amount of drift associated with the atmospheric sensor.

27. A computer-implemented method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device;

identifying a first set of estimated elevations that are within a threshold difference in elevation from each other, wherein the first set of estimated elevations are associated with a first set of positions of one or more mobile devices; and

determining, based on the first set of estimated elevations, a first estimated elevation of a first floor in a structure.

28. The computer-implemented method of claim 27, the method comprising:

identifying a second set of estimated elevations that are within the threshold difference in elevation from each other; and

determining, based on the second set of estimated elevations, a second estimated elevation of second floor in the structure.

29. A computer-implemented method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

calibrating the atmospheric sensor of the mobile device, wherein the atmospheric sensor is calibrated using aggregated reference data over a specified time period, or wherein the atmospheric sensor is calibrated when an elevation and atmospheric pressure at the position of the mobile device is known.

30. The computer-implemented method of claim 29, wherein the atmospheric sensor is calibrated using the aggregated reference data over the specified time period, the method comprising:

generating the aggregated reference data by identifying when the mobile device is at a known location; and

identifying deviations in the atmospheric data corresponding to the known location, wherein the atmospheric sensor is calibrated based on the deviations.

31. The computer-implemented method of claim 29, wherein the atmospheric sensor is calibrated when the elevation and atmospheric pressure at the position of the mobile device is known.

32. One or more non-transitory computer-readable media embodying program instructions adapted to be executed to implement a method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations; and

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device,

wherein the reference pressure estimate is determined based on a calculation using a first reference elevation pressure and a second reference elevation pressure, wherein the first reference elevation pressure is based on pressure and temperature measurements at a first location of a first reference sensor unit in addition to an elevation of the first reference sensor unit, and wherein the second reference elevation pressure is based on pressure and temperature measurements at a second location of a second reference sensor unit in addition to an elevation of the second reference sensor unit.

33. The non-transitory computer-readable media of claim 32, the method comprising:

generating the reference pressure estimate based on a pressure surface gradient model.

34. The non-transitory computer-readable media of claim 32, wherein the reference pressure estimate is generated after the first reference elevation pressure and the second reference elevation pressure are transmitted by one or more transmitters.

35. The non-transitory computer-readable media of claim 32, the method comprising:

generating the first reference elevation pressure using the pressure and the temperature measurements at the first location of the first reference sensor unit in addition to the elevation of the first reference sensor unit; and

generating the second reference elevation pressure using the pressure and the temperature measurements at the second location of the second reference sensor unit in addition to the elevation of the second reference sensor unit.

36. The non-transitory computer-readable media of claim 32, wherein the reference pressure estimate is generated by:

receiving, from a first reference sensor unit, a first reference elevation pressure associated with a first reference height, wherein the first reference elevation pressure is based on a first known height of the first reference sensor unit, a first pressure measured at a first location of the first reference sensor unit, and a first temperature measured at the first location;

receiving, from a second reference sensor unit, a second reference elevation pressure associated with the first reference height or a second reference height, wherein the second reference elevation pressure is based on a second known height of the second reference sensor unit, a second pressure measured at a second location of the second reference sensor unit, and a second temperature measured at the second location;

computing a first weighted reference elevation pressure based on the first reference elevation pressure and a first weight;

computing a second weighted reference elevation pressure based on the second reference elevation pressure and a second weight; and

generating the reference pressure estimate based on the first weighted reference elevation pressure and the second weighted reference elevation pressure.

37. The non-transitory computer-readable media of claim 32, the method comprising:

determining a variation of reference elevation pressure using the reference data from each of at least two reference sensor units; and

determining the reference pressure estimate based on the variation of reference elevation pressure.

38. The non-transitory computer-readable media of claim 32, the method comprising:

determining that the estimated elevation of the mobile device corresponds to a first floor of a building when the estimated elevation of the mobile device is within a threshold difference in elevation from a first estimated elevation of the first floor; and

determining that the estimated elevation of the mobile device corresponds to a second floor of the building when the estimated elevation of the mobile device is within the threshold difference in elevation from a second estimated elevation of the second floor.

39. One or more non-transitory computer-readable media embodying program instructions adapted to be executed to implement a method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining when the position of the mobile device is approximately at a known position;

after determining that the position of the mobile device is approximately at the known position, determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

determining a difference between the estimated elevation and a known height of known the position.

40. The non-transitory computer-readable media of claim 39, the method comprising:

calculating, based on the difference between the estimated elevation and the known height, a correction value associated with drift or aging related to the atmospheric sensor.

41. One or more non-transitory computer-readable media embodying program instructions adapted to be executed to implement a method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

determining, based on satellite signals, an estimated amount of drift associated with the atmospheric sensor.

42. One or more non-transitory computer-readable media embodying program instructions adapted to be executed to implement a method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device;

identifying a first set of estimated elevations that are within a threshold difference in elevation from each other, wherein the first set of estimated elevations are associated with a first set of positions of one or more mobile devices; and

determining, based on the first set of estimated elevations, an estimated elevation of a first floor in a structure.

43. The non-transitory computer-readable media of claim 42, the method comprising:

identifying a second set of estimated elevations that are within the threshold difference in elevation from each other; and

determining, based on the second set of estimated elevations, another estimated elevation of second floor in the structure.

44. One or more non-transitory computer-readable media embodying program instructions adapted to be executed to implement a method for estimating an elevation of a mobile device, the method comprising:

determining a reference pressure estimate associated with a position of a mobile device, wherein the reference pressure estimate is based on reference data from one or more reference sensor units that are positioned at respective known locations;

determining an estimated elevation of the mobile device using the reference pressure estimate and atmospheric data collected by an atmospheric sensor of the mobile device; and

calibrating the atmospheric sensor of the mobile device, wherein the atmospheric sensor is calibrated using aggregated reference data over a specified time period, or wherein the atmospheric sensor is calibrated when an elevation and atmospheric pressure at the position of the mobile device is known.

45. The non-transitory computer-readable media of claim 44, wherein the atmospheric sensor is calibrated using the aggregated reference data over the specified time period, the method comprising:

generating the aggregated reference data by identifying when the mobile device is at a known location; and

identifying deviations in the atmospheric data corresponding to the known location, wherein the atmospheric sensor is calibrated based on the deviations.

46. The non-transitory computer-readable media of claim 44, wherein the atmospheric sensor is calibrated when the elevation and atmospheric pressure at the position of the mobile device is known.