Systems and methods for differential altitude estimation utilizing spatial interpolation of pressure sensor data are provided. In one embodiment, a method for mobile navigation comprises: measuring a horizontal location of a mobile navigation unit to generate two-dimensional horizontal coordinate data; measuring a barometric pressure at the mobile navigation unit with a sensor to obtain local pressure data; processing information representative of pressure data derived from a network of a plurality reference stations to obtain a correction factor; performing a calculation using the two-dimensional horizontal coordinate data, the local pressure data, and the correction factor to calculate an altitude coordinate; and determining an altitude of the mobile navigation unit from the altitude coordinate.