Estimation of the location of a wireless terminal, based on a propagation characteristic of a pressure wave

A method of estimating the location of a wireless terminal, the method comprising:

• receiving, by a data processing system, a measurement of a location-dependent trait of a radio signal as received by a wireless terminal;
• receiving, by the data processing system, a sample of barometric pressure measured by the wireless terminal;
• generating, by the data-processing system, a characterization of a pressure wave in the vicinity of the wireless terminal based on the sample of barometric pressure measured by the wireless terminal;
• designating at least one of a plurality of possible locations of the wireless terminal as improbable based on:
• whether a predetermined feature is present in the characterization of the pressure wave;
• and
• estimating the location of the wireless terminal to be one of the plurality of possible locations of the wireless terminal not designated as improbable based on:
• the measurement of the location-dependent trait of the radio signal, and
• a propagation characteristic of the pressure wave, wherein the propagation characteristic of the pressure wave is its speed of propagation.

A method of estimating the location of a wireless terminal, the method comprising:

• receiving, by a data processing system, a sample of barometric pressure measured by a wireless terminal;
• generating, by the data-processing system, a characterization of a pressure wave in the vicinity of the wireless terminal based on the sample;
• and
• generating, by the data-processing system, an estimate of the location of the wireless terminal based on:
• i) the characterization of the pressure wave in the vicinity of the wireless terminal, and
• ii) a propagation characteristic of the pressure wave, wherein the propagation characteristic of the pressure wave is its speed of propagation, and
• iii) the location at which a predetermined event occurs that causes the pressure wave.