Managing states of location determination

• US 9,066,207 B2
• Filed: 12/14/2012
• Issued: 06/23/2015
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Marti, Lukas M., Mayor, Robert, Ma, Shannon M.
• Primary Examiner(s): SAMS, MATTHEW C
• Application Number:
  US13/715,710
• Publication Number:
  US 20140171068A1
• Time in Patent Office: 921 Days
• Field of Search: 4554561-457
• US Class Current: 1/1
• CPC Class Codes: G01S 1/047 Displays or indicators G01S1/06 takes precedence
• CPC Class Codes: G01S 1/06 Means for providing multiple indication, e.g. coarse and fine indications
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: H04W 4/025 using location based information parameters
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A mobile device can be in multiple states of location determination. In each state, the mobile device can use a distinct subsystem to determine a location. A state machine of the mobile device can manage the states, including determining which state the mobile device is in and whether a transition between the states has occurred. A transition can be triggered by a sensor of the mobile device and confirmed by another sensor of the mobile device. When the state machine detects a transition, the mobile device can switch location determination from one subsystem to another subsystem, and change a map user interface to one that is best suited for the new subsystem.

Claims

1. A method comprising:

determining, by a mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, wherein;

the venue-specific state corresponds to a state that the mobile device is located at a venue, the venue comprising a space accessible by a pedestrian and one or more constraints of movements of the pedestrian;

the venue-independent state corresponds to a state that the mobile device is not located at the venue; and

determining that the transition of states has occurred comprises;

determining a tentative location of the mobile device using measurements of signals from one or more signal sources; and

at least one of;

determining that a transition from the venue-specific state to the venue-independent state has occurred upon determining that an error margin of the tentative location exceeds a convergence threshold, or determining that the mobile device has transitioned from the venue-independent state to the venue-specific state upon determining that at least one measurement of signals from at least a threshold number of the one or more signal sources satisfies an entrance threshold; and

in response to determining that the transition of state has occurred, determining, by the mobile device, a second location of the mobile device using the second subsystem.

2. The method of claim 1, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

3. The method of claim 1, comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

4. The method of claim 1, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

5. The method of claim 4, wherein determining that the transition of state has occurred comprises:

detecting that the mobile device has transitioned from the venue-specific state to the venue-independent state when the mobile device cannot detect signals from the one or more signal sources or when each measurement of signals from each of the one or more signal sources satisfies an exit threshold.

6. The method of claim 5, wherein the entrance threshold is higher than the exit threshold.

7. A system comprising:

a mobile device; and

a non-transitory computer-readable medium storing instructions operable to cause the mobile device to perform operations comprising;

determining a first location of the mobile device using a first subsystem of the mobile device;

determining that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, wherein;

the venue-specific state corresponds to a state that the mobile device is located at a venue, the venue comprising a space accessible by a pedestrian and one or more constraints of movements of the pedestrian;

the venue-independent state corresponds to a state that the mobile device is not located at the venue; and

determining that the transition of states has occurred comprises;

determining a tentative location of the mobile device using measurements of signals from one or more signal sources; and

at least one of;

determining that a transition from the venue-specific state to the venue-independent state has occurred upon determining that an error margin of the tentative location exceeds a convergence threshold, or determining that the mobile device has transitioned from the venue-independent state to the venue-specific state upon determining that at least one measurement of signals from at least a threshold number of the one or more signal sources satisfies an entrance threshold; and

in response to determining that the transition of state has occurred, determining a second location of the mobile device using the second subsystem.

8. The system of claim 7, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

9. The system of claim 7, comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

10. The system of claim 7, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

11. The system of claim 10, wherein determining that the transition of state has occurred comprises:

detecting that the mobile device has transitioned from the venue-specific state to the venue-independent state when the mobile device cannot detect signals from the one or more signal sources or when each measurement of signals from each of the one or more signal sources satisfies an exit threshold.

12. The system of claim 11, wherein the entrance threshold is higher than the exit threshold.

13. A non-transitory computer-readable medium storing instructions operable to cause one or more processors to perform operations comprising:

determining, by a mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, wherein;

the venue-specific state corresponds to a state that the mobile device is located at a venue, the venue comprising a space accessible by a pedestrian and one or more constraints of movements of the pedestrian;

the venue-independent state corresponds to a state that the mobile device is not located at the venue; and

determining that the transition of states has occurred comprises;

determining a tentative location of the mobile device using measurements of signals from one or more signal sources; and

at least one of;

determining that a transition from the venue-specific state to the venue-independent state has occurred upon determining that an error margin of the tentative location exceeds a convergence threshold, or determining that the mobile device has transitioned from the venue-independent state to the venue-specific state upon determining that at least one measurement of signals from at least a threshold number of the one or more signal sources satisfies an entrance threshold; and

in response to determining that the transition of state has occurred, determining, by the mobile device, a second location of the mobile device using the second subsystem.

14. The non-transitory computer-readable medium of claim 13, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

15. The non-transitory computer-readable medium of claim 13, comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

16. The non-transitory computer-readable medium of claim 13, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

17. The non-transitory computer-readable medium of claim 16, wherein determining that the transition of state has occurred comprises:

detecting that the mobile device has transitioned from the venue-specific state to the venue-independent state when the mobile device cannot detect signals from the one or more signal sources or when each measurement of signals from each of the one or more signal sources satisfies an exit threshold.

18. The non-transitory computer-readable medium of claim 17, wherein the entrance threshold is higher than the exit threshold.

19. A method comprising:

determining, by a mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that a probability that the transition has occurred has reached a threshold;

triggering a measurement by a barometric pressure sensor of the mobile device upon the determining, the barometric pressure sensor configured to detect air pressure change indicative of a movement of the mobile device between floors of a building; and

then

confirming that the transition has occurred based on readings of the barometric pressure sensor; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

20. The method of claim 19, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

21. The method of claim 19, comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

22. The method of claim 19, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

23. A system comprising:

a mobile device; and

a non-transitory computer-readable medium storing instructions operable to cause the mobile device to perform operations comprising;

determining, by the mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that a probability that the transition has occurred has reached a threshold;

triggering a measurement by a barometric pressure sensor of the mobile device upon the determining, the barometric pressure sensor configured to detect air pressure change indicative of a movement of the mobile device between floors of a building; and

then

confirming that the transition has occurred based on readings of the barometric pressure sensor; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

24. The system of claim 23, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

25. The system of claim 23, the operations comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

26. The system of claim 23, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

27. A non-transitory computer-readable medium storing instructions operable to cause a mobile device to perform operations comprising:

determining a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that a probability that the transition has occurred has reached a threshold;

triggering a measurement by a barometric pressure sensor of the mobile device upon the determining, the barometric pressure sensor configured to detect air pressure change indicative of a movement of the mobile device between floors of a building; and

then

confirming that the transition has occurred based on readings of the barometric pressure sensor; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

28. The non-transitory computer-readable medium of claim 27, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

29. The non-transitory computer-readable medium of claim 27, the operations comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

30. The non-transitory computer-readable medium of claim 27, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

31. A method comprising:

determining, by a mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that a probability that the transition has occurred has reached a threshold;

triggering a measurement using at least one of a hygrometer of the mobile device or a microphone of the mobile device upon the determining; and

then

confirming that the transition has occurred when;

a difference between a first humidity reading of the hygrometer and a second humidity reading of the hygrometer satisfied an estimated threshold humidity difference between an indoor environment and an outdoor environment, or

a difference between a first noise level reading of the microphone and a second noise level reading of the microphone satisfied an estimated threshold noise level difference between an indoor environment and an outdoor environment; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

32. The method of claim 31, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

33. The method of claim 31, comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

34. The method of claim 31, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

35. A system comprising:

a mobile device; and

a non-transitory computer-readable medium storing instructions operable to cause the mobile device to perform operations comprising;

determining, by the mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that a probability that the transition has occurred has reached a threshold;

triggering a measurement using at least one of a hygrometer of the mobile device or a microphone of the mobile device upon the determining; and

then

confirming that the transition has occurred when;

a difference between a first humidity reading of the hygrometer and a second humidity reading of the hygrometer satisfied an estimated threshold humidity difference between an indoor environment and an outdoor environment, or

a difference between a first noise level reading of the microphone and a second noise level reading of the microphone satisfied an estimated threshold noise level difference between an indoor environment and an outdoor environment; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

36. The system of claim 35, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

37. The system of claim 35, the operations comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

38. The system of claim 35, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

39. A non-transitory computer-readable medium storing instructions operable to cause a mobile device to perform operations comprising:

determining, by the mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that a probability that the transition has occurred has reached a threshold;

triggering a measurement using at least one of a hygrometer of the mobile device or a microphone of the mobile device upon the determining; and

then

confirming that the transition has occurred when;

a difference between a first humidity reading of the hygrometer and a second humidity reading of the hygrometer satisfied an estimated threshold humidity difference between an indoor environment and an outdoor environment, or

a difference between a first noise level reading of the microphone and a second noise level reading of the microphone satisfied an estimated threshold noise level difference between an indoor environment and an outdoor environment; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

40. The non-transitory computer-readable medium of claim 39, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

41. The non-transitory computer-readable medium of claim 39, the operations comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

42. The non-transitory computer-readable medium of claim 39, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

43. A method comprising:

determining, by a mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that an estimated location of the mobile device is outside of a footprint of a venue, the footprint being an area determined based on a shape and a size of the venue and a location calculation error margin, wherein the location calculation error margin is an error margin of a location calculated by the mobile device using measurements of signals from one or more signal sources if the mobile device is located at the venue; and

then

determining that the mobile device has transitioned from the venue-specific state to the venue-independent state; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

44. The method of claim 43, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

45. The method of claim 43, comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

46. The method of claim 43, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

47. A system comprising:

a mobile device; and

a non-transitory computer-readable medium storing instructions operable to cause the mobile device to perform operations comprising;

determining, by the mobile device, a first location of the mobile device using a first subsystem of the mobile device;

determining, by the mobile device, that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that an estimated location of the mobile device is outside of a footprint of a venue, the footprint being an area determined based on a shape and a size of the venue and a location calculation error margin, wherein the location calculation error margin is an error margin of a location calculated by the mobile device using measurements of signals from one or more signal sources if the mobile device is located at the venue; and

then

determining that the mobile device has transitioned from the venue-specific state to the venue-independent state; and

determining, by the mobile device, a second location of the mobile device using the second subsystem.

48. The system of claim 47, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

49. The system of claim 47, the operations comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

50. The system of claim 47, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.

51. A non-transitory computer-readable medium storing instructions operable to cause a mobile device to perform operations comprising:

determining a first location of the mobile device using a first subsystem of the mobile device;

determining that a transition of state has occurred, the transition of state indicating that, after the transition, a location estimation by a second subsystem of the mobile device is expected to be more accurate than a location estimation by the first subsystem, wherein the transition of state comprises transitioning from a venue-specific state to a venue-independent state or transitioning from a venue-independent state to a venue-specific state, and wherein determining that the transition of states has occurred comprises;

determining that an estimated location of the mobile device is outside of a footprint of a venue, the footprint being an area determined based on a shape and a size of the venue and a location calculation error margin, wherein the location calculation error margin is an error margin of a location calculated by the mobile device using measurements of signals from one or more signal sources if the mobile device is located at the venue; and

then

determining that the mobile device has transitioned from the venue-specific state to the venue-independent state; and

determining a second location of the mobile device using the second subsystem.

52. The non-transitory computer-readable medium of claim 51, wherein:

one of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from a global satellite system, and

another of the first subsystem or second subsystem is configured to determine a location of the mobile device using signals from one or more wireless access points.

53. The non-transitory computer-readable medium of claim 51, the operations comprising:

upon determining that the transition of states has occurred, switching a display of the mobile device from displaying a first user interface configured for presenting the first location to displaying a second user interface configured for presenting the second location, wherein;

the first user interface includes a map of an interior of a building, and

the second user interface includes a street map.

54. The non-transitory computer-readable medium of claim 51, wherein:

the venue is associated with a location fingerprint database, the location fingerprint database comprising a plurality of location fingerprints of the venue, each location fingerprint being associated with a sample location in the venue and including expected measurements of signals from one or more signal sources by a mobile device located at the sample location.