CPC G01C 5/06 (2013.01) [G01D 21/02 (2013.01); G06F 17/18 (2013.01)] | 20 Claims |
1. A method comprising:
determining, by a processing system including a processor, that a plurality of mobile devices is at ground level;
obtaining, by the processing system for the plurality of mobile devices, positions and barometric pressure readings;
for each mobile device of the plurality of mobile devices:
comparing, by the processing system, a speed of the mobile device to a speed threshold to obtain a comparison result; and
inferring, by the processing system, a mode of transportation according to the comparison result;
determining, by the processing system for the plurality of mobile devices, ground heights with respect to a common reference height to obtain determined ground heights, wherein for each mobile device of the plurality of mobile devices, the determined ground height comprises a sum of a ground elevation above the common reference height corresponding to a position of the mobile device and an offset elevation based at least in part on the mode of transportation of the mobile device;
combining, by the processing system for the plurality of mobile devices, reference barometric pressures at the common reference height according to the barometric pressure readings and the determined ground heights, to obtain a combined reference pressure; and
determining, by the processing system, a height of a target device above a local ground position of the target device, in accordance with a reported barometric pressure at the target device and the combined reference pressure.
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