Systems and methods for determining a height of a mobile device above a surface
Determining one or more heights of one or more mobile devices above surfaces. Particular embodiments described herein include machines that retrieve first data (e.g., measurement value(s) determined by sensor(s) of a mobile device or estimated position(s) of the mobile device), determine a location context based on the first data, identify second data (e.g., measurement value(s) determined by sensor(s) of the mobile device or status indicator value(s) of feature(s) of the mobile device) to retrieve for use in determining an estimated height above a surface at which the mobile device is located based on the determined location context, retrieve the second data, and determine an estimated height above a surface at which the mobile device is located based on the retrieved second data.
1. A method comprising:
retrieving first data that comprises at least one measurement value determined by at least one sensor of a mobile device;
determining a location context based on the first data;
retrieving second data that is of a type that is associated with the determined location context;
determining, based on the retrieved second data, an estimated height at which the mobile device is located above a surface; and
calibrating a pressure sensor of the mobile device based on the estimated height at which the mobile device is located above the surface, estimating an altitude of the mobile device as a sum of an altitude of the surface and the estimated height at which the mobile device is located above the surface, or determining an estimated altitude of the surface as a difference between an estimated altitude of the mobile device and the estimated height at which the mobile device is located above the surface;
wherein determining the location context comprises:
determining that the location context specifies the mobile device as being with a user who is on foot when the at least one measurement value is indicative of a movement associated with a walking or running user;
determining that the location context specifies the mobile device as being on or with a user who is on a bike when the at least one measurement value is indicative of a movement associated with a moving bike;
determining that the location context specifies the mobile device as being in a vehicle when the at least one measurement value is indicative of a movement associated with a moving vehicle;
determining that the location context specifies the mobile device as being stationary when the at least one measurement value is indicative of no movement; or
determining that the location context specifies the mobile device as being on a surface after being dropped when the at least one measurement value is indicative of resting after falling.
2. The method of claim 1 , wherein:
the at least one measurement value is indicative of a movement associated with a walking or running user when (i) the at least one measurement value represents a stepping movement of the user recorded over time, or (ii) the at least one measurement value includes periodic measurements of an angular orientation from a gyroscope that is indicative of an orientation at which a mobile device is periodically positioned while being carried by a user who is walking or running.
3. The method of claim 1 , wherein:
the at least one measurement value is indicative of movement associated with a moving bike when (i) a measured spread of up and down Z-accelerations exceeds a threshold value for a percent of time during which Z-accelerations are measured, or (ii) a measured spread of increases and decreases of XY-accelerations exceeds a threshold value for a percent of time during which XY-accelerations are measured.
4. The method of claim 1 , wherein:
the at least one measurement value is indicative of a movement associated with a moving vehicle when (i) a measured spread of up and down Z-accelerations exceeds a threshold value for a percent of time during which Z-accelerations are measured, or (ii) a measured spread of increases and decreases of XY-accelerations exceeds a threshold value for a percent of time during which XY-accelerations are measured.
5. The method of claim 1 , wherein:
the at least one measurement value is indicative of no movement when (i) a difference between two readings of an accelerometer that are measured within a predefined amount of time of each other is below an acceleration threshold, or (ii) an angular separation between two orientation readings of a gyroscope that are measured within another predefined amount of time of each other is below an orientation threshold.
6. The method of claim 1 , wherein:
the at least one measurement value is indicative of resting after falling when (i) an accelerometer of the mobile device measures a large impact via a sudden change in Z-axis acceleration from one measurement to another measurement that exceeds a threshold amount of change, or (ii) the accelerometer of the mobile device measures no Z-axis acceleration after a measurement of Z-axis acceleration associated with falling.
7. The method of claim 1 , wherein:
the at least one measurement value is indicative of a movement associated with a moving vehicle when the at least one measurement value is indicative of turbulent conditions quantified as (i) a variance or standard deviation of the at least one measurement value over a time period that exceeds a threshold, or (ii) a range of the at least one measurement value over the time period that exceeds a threshold.
8. A system comprising one or more machines configured to perform the method of claim 1 .
9. One or more non-transitory processor-readable media embodying program instructions that, when executed by one or more machines, cause the one or more machines to implement the method of claim 1 .
10. A method comprising:
retrieving first data that comprises at least one estimated position of a mobile device;
determining a location context based on the first data;
retrieving second data that is of a type that is associated with the determined location context;
determining, based on the retrieved second data, an estimated height at which the mobile device is located above a surface; and
calibrating a pressure sensor of the mobile device based on the estimated height at which the mobile device is located above the surface, estimating an altitude of the mobile device as a sum of an altitude of the surface and the estimated height at which the mobile device is located above the surface, or determining an estimated altitude of the surface as a difference between an estimated altitude of the mobile device and the estimated height at which the mobile device is located above the surface;
wherein:
the first data includes two or more estimated positions of the mobile device; and
determining the location context comprises:
determining that the location context specifies the mobile device as being with a user who is on foot when the two or more estimated positions are indicative of a movement associated with a walking or running user;
determining that the location context specifies the mobile device as being on or with a user who is on a bike when the two or more estimated positions are indicative of a movement associated with a bike;
determining that the location context specifies the mobile device as being in a vehicle when the two or more estimated positions are indicative of a movement associated with a vehicle;
determining that the location context specifies the mobile device as being stationary when the two or more estimated positions are indicative of a movement associated with being stationary; or
determining that the location context specifies the mobile device as being on a surface after being dropped when the two or more estimated positions are indicative of a movement associated with falling to and landing on the surface.
11. The method of claim 10 , wherein:
the two or more estimated positions are indicative of a movement associated with a walking or running user when a velocity of the mobile device calculated by dividing a distance between two of the two or more estimated positions by a time elapsed between when each of the estimated positions was determined is above a threshold associated with a minimum walking speed and below a threshold associated with a maximum running speed.
12. The method of claim 10 , wherein:
the two or more estimated positions are indicative of a movement associated with a bike when a velocity of the mobile device calculated by dividing a distance between two of the two or more estimated positions by a time elapsed between when each of the estimated positions was determined is above a threshold associated with a maximum running speed and below a threshold associated with a maximum bike speed or associated with a speed below which a vehicle is unlikely to be traveling.
13. The method of claim 10 , wherein:
the two or more estimated positions are indicative of a movement associated with a vehicle when a velocity of the mobile device calculated by dividing a distance between two of the two or more estimated positions by a time elapsed between when each of the estimated positions was determined is i) above a threshold associated with a maximum bike speed or associated with a speed below which a vehicle is unlikely to be traveling, and ii) below a threshold associated with a maximum speed of a vehicle.
14. The method of claim 10 , wherein:
the two or more estimated positions are indicative of a movement associated with being stationary when a velocity of the mobile device calculated by dividing a distance between two of the two or more estimated positions by a time elapsed between when each of the estimated positions was determined is below a threshold associated with a minimum walking speed.
15. The method of claim 10 , wherein:
the two or more estimated positions are indicative of a movement associated with being stationary when a velocity of the mobile device calculated by dividing a distance between two of the two or more estimated positions by a time elapsed between when each of the estimated positions was determined is below a threshold associated with a minimum walking speed and when a vertical velocity of the mobile device is below a vertical velocity threshold.
16. The method of claim 10 , wherein:
the two or more estimated positions of the mobile device include a first estimated position and a second estimated position; and
the two or more estimated positions are indicative of a movement associated with falling to and landing on the surface when the second estimated position is lower than the first estimated position, and a vertical velocity of the mobile device calculated by dividing a Z distance between the two estimated positions by a time elapsed between when each of the estimated positions was determined is above a vertical velocity threshold.
17. The method of claim 10 , wherein:
the two or more estimated positions of the mobile device include a first estimated position and a second estimated position; and
the two or more estimated positions are indicative of a movement associated with falling to and landing on the surface when the second estimated position is lower than the first estimated position, a vertical velocity of the mobile device calculated by dividing a Z distance between the two estimated positions by a time elapsed between when each of the estimated positions was determined is above a vertical velocity threshold, and a horizontal velocity of the mobile device calculated by dividing an XY distance between the first and second estimated positions by the time elapsed between when each of the estimated positions was determined is below a threshold associated with a minimum walking speed.
18. A method comprising:
retrieving first data that comprises at least one estimated position of a mobile device;
determining a location context based on the first data;
retrieving second data that is of a type that is associated with the determined location context;
determining, based on the retrieved second data, an estimated height at which the mobile device is located above a surface; and
calibrating a pressure sensor of the mobile device based on the estimated height at which the mobile device is located above the surface, estimating an altitude of the mobile device as a sum of an altitude of the surface and the estimated height at which the mobile device is located above the surface, or determining an estimated altitude of the surface as a difference between an estimated altitude of the mobile device and the estimated height at which the mobile device is located above the surface;
and wherein:
the first data includes an estimated position of the mobile device; and
determining the location context comprises determining that the location context specifies the mobile device as being (i) with a user who is on foot if the estimated position is on or within a threshold distance to a venue where the user is likely to be walking or running with the mobile device, (ii) on or with a user who is on a bike if the estimated position is on or within a threshold distance to a bike path where the user is likely to be riding a bike with the mobile device, (iii) in a vehicle if the estimated position is on or within a threshold distance to a highway or expressway, or (iv) stationary if the estimated position is at the user's residence or workplace.