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;
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, 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 the mobile device is periodically positioned while being carried by the user who is walking or running; or
determining that the location context specifies the mobile device as being stationary when the at least one measurement value is indicative of no movement, 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.
2. A system comprising one or more machines configured to perform the method of claim 1 .
3. The method of claim 1 , wherein:
the second data is one or more of at least one second measurement value determined by the at least one sensor of the mobile device or at least one status indicator value of a feature of the mobile device.
4. 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;
wherein determining the location context comprises:
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, wherein the at least one measurement value is indicative of the movement associated with the 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;
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, wherein the at least one measurement value is indicative of the movement associated with the 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, (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, (iii) the at least one measurement value is indicative of turbulent conditions quantified as a variance or standard deviation of the at least one measurement value over a time period that exceeds a first threshold, or (iv) the at least one measurement value is indicative of turbulent conditions quantified as a range of the at least one measurement value over the time period that exceeds a second threshold; or
determining that the location context specifies the mobile device as being on the surface after being dropped when the at least one measurement value is indicative of resting after falling, 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.
5. A system comprising one or more machines configured to perform the method of claim 4 .
6. The method of claim 4 , wherein:
the second data is one or more of at least one second measurement value determined by the at least one sensor of the mobile device or at least one status indicator value of a feature of the mobile device.
7. 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
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;
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, 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 the mobile device is periodically positioned while being carried by the user who is walking or running; or
determining that the location context specifies the mobile device as being stationary when the at least one measurement value is indicative of no movement, 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.
8. A system comprising one or more machines configured to perform the method of claim 7 .
9. The method of claim 7 , wherein:
the second data is one or more of at least one second measurement value determined by the at least one sensor of the mobile device or at least one status indicator value of a feature of the mobile device.
10. 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
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;
wherein determining the location context comprises:
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, wherein the at least one measurement value is indicative of the movement associated with the 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;
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, wherein the at least one measurement value is indicative of the movement associated with the 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, (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, (iii) the at least one measurement value is indicative of turbulent conditions quantified as a variance or standard deviation of the at least one measurement value over a time period that exceeds a first threshold, or (iv) the at least one measurement value is indicative of turbulent conditions quantified as a range of the at least one measurement value over the time period that exceeds a second threshold; or
determining that the location context specifies the mobile device as being on the surface after being dropped when the at least one measurement value is indicative of resting after falling, 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.
11. A system comprising one or more machines configured to perform the method of claim 10 .
12. The method of claim 10 , wherein:
the second data is one or more of at least one second measurement value determined by the at least one sensor of the mobile device or at least one status indicator value of a feature of the mobile device.