A method and system are provided for performing satellite-supported landings in CAT II/III type landing conditions. An exemplary system includes a communication component, a positioning system, a radar altimeter, and a processor. The communication component receives terrain data information related to an instrument landing approach. The positioning system determines position of the aircraft. The radar altimeter generates altitude information of the aircraft. The processor is coupled to the communication component, the positioning system, and the radar altimeter. The processor determines an aircraft altitude based on the determined position of the aircraft, received terrain data information, and the generated altitude information.