Calibrating a device for determining position in three-dimensional space

Abstract

To calibrate a device, a system receives an indication of current weather conditions at a geographic area, obtains, from a database, elevation data for the geographic area, and generating expected measurements of atmospheric pressure at the geographic area using the indication of weather conditions and the elevation data for the geographic area. The system then causes at least one mobile device located in the geographic area and equipped with a barometer to calibrate the barometer using the expected measurements of atmospheric pressure.

What is claimed is: 
     
         1 . A method of calibrating devices, the method comprising:
 receiving, by one or more processors, an indication of current weather conditions at a geographic area;   obtaining, by the one or more processors from a database, elevation data for the geographic area;   generating, by the one or more processors, expected measurements of atmospheric pressure at the geographic area using the indication of weather conditions and the elevation data for the geographic area; and   causing at least one mobile device located in the geographic area and equipped with a barometer to calibrate the barometer using the expected measurements of atmospheric pressure.   
     
     
         2 . The method of  claim 1 , wherein generating the expected measurements includes generating air pressure measurements expected at a particular time and at a geographic location of the mobile device. 
     
     
         3 . The method of  claim 1 , wherein
 generating the expected measurements of atmospheric pressure is in response to receiving a request from the mobile device.   
     
     
         4 . The method of  claim 3 , further comprising:
 generating a unique token for the request;   storing, in a database, the unique token along with calibration data for the mobile device, including not storing identity of the mobile device; and   providing the calibration data in response to receiving the unique token.   
     
     
         5 . The method of  claim 1 , wherein obtaining the elevation data includes determining a floor at which the mobile device is located. 
     
     
         6 . The method of  claim 1 , further comprising:
 subsequently to causing the mobile device to calibrate the barometer, obtaining pressure data from the mobile device;   determining that a peer device is disposed near the mobile device at a same elevation;   determining that location sharing is enabled at the mobile device; and   providing the pressure data to the peer device.   
     
     
         7 . A method in a mobile device for calibrating a barometer, the method comprising:
 transmitting, by processing hardware to a network server, a request for measurements of atmospheric pressure expected at a particular time and at a geographic location of the mobile device;   receiving, in response to the request, the expected measurements of atmospheric pressure; and   calibrating, by the processing hardware and using the expected measurements, the barometer.   
     
     
         8 . The method of  claim 7 , further comprising:
 re-initiating the calibrating of the barometer after a predetermined period of time.   
     
     
         9 . The method of  claim 7 , further comprising:
 subsequently calibrating the barometer, obtaining an air pressure measurement using the calibrated barometer, by the processing hardware;   applying, by the processing hardware, the air pressure measurement to a meteorological forecast model to obtain weather data.   
     
     
         10 . The method of  claim 9 , further comprising:
 providing the weather data to a nearby peer device.   
     
     
         11 . The method of  claim 9 , further comprising:
 providing the air pressure measurement to a nearby peer device.   
     
     
         12 . The method of  claim 7 , further comprising:
 positioning the mobile device in a three-dimensional space using the calibrated barometer.   
     
     
         13 . A system comprising:
 one or more processors;   a non-transitory computer-readable medium storing instructions that, when executed by the one or more processors, cause the system to:
 receive an indication of current weather conditions at a geographic area, 
 obtaining, from a database, elevation data for the geographic area, 
 generate expected measurements of atmospheric pressure at the geographic area using the indication of weather conditions and the elevation data for the geographic area, and 
 cause at least one mobile device located in the geographic area and equipped with a barometer to calibrate the barometer using the expected measurements of atmospheric pressure. 
   
     
     
         14 . The system of  claim 13 , wherein generating the expected measurements includes generating air pressure measurements expected at a particular time and at a geographic location of the mobile device. 
     
     
         15 . The system of  claim 13 , wherein generating the expected measurements of atmospheric pressure is in response to receiving a request from the mobile device. 
     
     
         16 . The system of  claim 15 , wherein the instructions further cause the system to:
 generate a unique token for the request;   store, in a database, the unique token along with calibration data for the mobile device, including not storing identity of the mobile device; and   provide the calibration data in response to receiving the unique token.   
     
     
         17 . The system of  claim 13 , wherein obtaining the elevation data includes determining a floor at which the mobile device is located. 
     
     
         18 . The system of  claim 13 , wherein the instructions further cause the system to:
 subsequently to causing the mobile device to calibrate the barometer, obtain pressure data from the mobile device;   determine that a peer device is disposed near the mobile device at a same elevation;   determine that location sharing is enabled at the mobile device; and   provide the pressure data to the peer device.