US Patent 9057606 Wide area positioning system

Systems and methods compute an estimated altitude of a receiver using atmospheric data, including a pressure measured at a location of the receiver, a temperature measured by at a reference location, and a reference pressure corresponding to the reference location. The reference pressure is based on a pressure measured at the reference location, the temperature measured at the reference location, and an altitude corresponding to the reference location. The receiver receives the reference pressure from a transmitter. The estimated altitude may be used for determining the three-dimensional position of the receiver.