Abstract: Determining when to calibrate a pressure sensor of a mobile device. Particular systems and methods determine values of a plurality of metrics, determine weights for the metric values, determine weighted metric values by applying the weights to the metric values, use the weighted metric values to determine if a pressure sensor of the mobile device should be calibrated using information associated with the first location, and calibrate the pressure sensor of the mobile device using the information associated with the first location if a determination is made that the pressure sensor of the mobile device should be calibrated using information associated with the first location.

Abstract: Using a pressure sensor of a mobile device to improve the accuracy of determined contexts. Particular embodiments described herein include machines that determine a context of a mobile device, and determine if the determined context is accurate using multiple measurements of pressure from a pressure sensor of the mobile device.

Abstract: Determining when to calibrate a pressure sensor of a mobile device. Particular systems and methods determine values of a plurality of metrics based on how data collected at a first location of a mobile device relates to threshold conditions, determine weights for the metric values, determine weighted metric values by applying the weights to the metric values, use the weighted metric values to determine if a pressure sensor of the mobile device should be calibrated using information associated with the first location, and calibrate the pressure sensor of the mobile device using the information associated with the first location if a determination is made that the pressure sensor of the mobile device should be calibrated using information associated with the first location.

Abstract: Using a pressure sensor of a mobile device to improve the reliability of determined contexts. Particular embodiments described herein include machines that determine a context of a mobile device, and determine if the determined context is accurate using one or more measurements of pressure from a pressure sensor of the mobile device.

Abstract: Determining calibration values for atmospheric sensors that provide measured pressures used for estimating altitudes of mobile devices. Particular systems and methods determine if any uncalibrated reference-level pressure estimates associated with an unstable pressure sensor should not be used when calibrating the unstable pressure sensor, and calibrate the unstable pressure sensor using all of the uncalibrated reference-level pressure estimates except any uncalibrated reference-level pressure estimate that should not be used when calibrating the unstable pressure sensor.

Abstract: Methods and machines involve detecting when a mobile device is in a first area and a second area at different times, collecting pressure data from the mobile device and reference sensor(s) to estimate altitudes of the mobile device within the first area and the second area, collecting terrain altitudes associated with the first area and the second area, and using a difference between the estimated altitudes and a difference between the terrain altitudes to determine a height of a floor. The estimated floor height may be used to calibrate a pressure sensor of a mobile device.

Abstract: Determining contexts of mobile devices. Particular embodiments described herein include machines that determine two estimated positions of a mobile device that respectively correspond to first and second locations at first and second times, acquire sets of terrain or structural information for first and second areas that respectively include the first and second estimated positions, use the acquired sets of information and the estimated positions to determine if the mobile device was within a structure at the first and second times, determine one or more values that are indicative of vertical movement by the mobile device during a period of time between the first time and the second time, compare the one or more values to one or more threshold conditions, and determine a context of the mobile device based on the comparison.

Abstract: Determining calibration values for atmospheric sensors that provide measured pressures used for estimating altitudes of mobile devices. Particular systems and methods determine if any uncalibrated reference-level pressure estimates associated with an unstable pressure sensor should not be used when calibrating the unstable pressure sensor, and calibrate the unstable pressure sensor using all of the uncalibrated reference-level pressure estimates except any uncalibrated reference-level pressure estimate that should not be used when calibrating the unstable pressure sensor.

Abstract: Using a pressure sensor of a mobile device to improve the reliability of determined contexts. Particular embodiments described herein include machines that determine a context of a mobile device, and determine if the determined context is accurate using one or more measurements of pressure from a pressure sensor of the mobile device.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Identifying and estimating values of atmospheric conditions for use in estimating an altitude of a mobile device. Systems and methods for monitoring one or more conditions before estimating an altitude of a mobile device may receive a reference pressure that was computed using a measurement of pressure from a first reference pressure sensor at a first location, wherein the received reference pressure specifies an estimated pressure for a reference altitude, and determine if a threshold change in measured pressure by the first reference pressure sensor is detected. If the threshold change in measured pressure is detected, the systems and methods may compute a calibration value for the first reference pressure sensor, or if the threshold change in measured pressure is not detected, the systems and methods may identify a previously-determined calibration value.

Abstract: Using atmospheric data from one or more reference nodes to estimate an altitude of a receiver. Assistance data associated with a set of reference nodes within a region is identified, and the assistance data is used to identify atmospheric reference data associated with a subset of selected reference nodes. An estimate of the receiver's altitude is generated using the atmospheric reference data from the subset of reference nodes.

Abstract: Determining an altitude error value associated with an estimated altitude of a mobile device. In certain disclosed systems and methods for determining an altitude error value associated with an estimated altitude of a mobile device, a first error value related to systematic error and a second error value related to statistical error are determined, and the altitude error value is determined using the first error value and the second error value.

Abstract: Pressure-based estimation of a mobile device altitude or calibration of a pressure sensor. Particular embodiments described herein include machines that determine if a reference-level pressure value based on one or more measurements of pressure from a network of weather stations should or should not be used to calibrate a pressure sensor of a mobile device or to estimate an altitude of the mobile device. If a first determination is made that the reference-level pressure value should be used, the reference-level pressure value is used to calibrate a pressure sensor of a mobile device or to estimate an altitude of the mobile device.

Abstract: Determining an indoor or outdoor location of a mobile device. Particular embodiments described herein determine a geographic area of potential locations in which a mobile device resides, identify any buildings that occupy part of the geographic area, and determine if the mobile device does not reside inside any building, the mobile device resides inside a particular building from the identified buildings, or that one or more of the identified buildings are candidate buildings in which the mobile device may reside based on the geographic area and building footprints of the identified buildings.

Abstract: Improving an estimated altitude of a receiver by mitigating the effects of transmitter heating. Systems and methods for improving estimates of a receiver's altitude determine a reference pressure at a reference altitude using a temperature measured at a transmitter or another temperature value, an altitude of the transmitter, and a pressure measured by the transmitter or another pressure value. A local reference pressure for a receiver is determined using the reference pressure and other reference pressures from other transmitters. Reference pressures from overheating transmitters may be weighted less than reference pressures from other transmitters when determining the local reference pressure. The local reference pressure is then used to estimate the altitude of the receiver.

Abstract: Calibrating an unstable sensor of a mobile device. Systems and methods for calibrating a sensor of a mobile device determine a first estimated position of the mobile device without using any measurement from the sensor of the mobile device, generate a second estimated position of the mobile device using a measurement from the sensor, estimate a sensor error of the sensor using the first estimated position and the second estimated position, and use the sensor error to determine a calibration value for adjusting one or more measurements from the sensor.

Abstract: Extending the spatial coverage of a reference pressure network. Particular embodiments described herein include machines that initially determine that an estimated position of a mobile device resides outside a coverage area of a network of reference pressure sensors. Reference-level pressures corresponding to reference pressure sensors of the network are determined using measurements of pressure from the network of reference pressure sensors. A pressure pattern for a region that includes the estimated position and an area not included in the coverage area of the network is determined using reference-level pressures that were not determined using measurements of pressure from the network of reference pressure sensors. The reference-level pressures corresponding to reference pressure sensors of the network and the pressure pattern are used to determine a reference-level pressure value for use in calibrating a pressure sensor of the mobile device or for use in estimating an altitude of the mobile device.