Estimating elevation of a wireless terminal, based on the measurement bias of a pressure reference that is in a second region, based on the measurement bias of a pressure reference that is in a first region

A location engine that estimates the barometric pressure measurement bias of a pressure station reference, such as an airport pressure station, resulting in an improved estimate of the elevation of a wireless terminal. The location engine generates the estimate of bias of barometric pressure by comparing i) the outdoor barometric pressure measured by the airport pressure station at its unknown height above mean sea level (MSL) and ii) the expected outdoor barometric pressure derived from the pressure measurements from an already-calibrated pressure station, while accounting for the known height of the already-calibrated pressure station. The expected outdoor measurements correspond to a derived height above MSL of the airport pressure station. Subsequently, the location engine generates an estimate of the elevation of the wireless terminal by accounting for the estimate of measurement bias of the airport pressure station.