US Patent 11852554 Barometer calibration in a location sharing system

Methods, systems, and devices for calibrating a barometer of a client device. A server computer accesses historical data including location data, and atmospheric pressure data collected from a plurality of client devices over a period of time. An equation system defined by the historical data is solved. The equation system has a plurality of unknown parameters, the plurality of unknown parameters comprising a barometer bias of a first client device among the plurality of client devices. The first client device is calibrated using the barometer bias.