Patent ID: 7831341

Claim:
A method for determining navigational data using modulated celestial radiation, the method comprising the steps of: selecting a localized reference point in a reference frame; receiving modulated radiation at a reception point in said reference frame from at least one celestial source, said reception point located an unknown distance from said reference point, each said source located along a line in a corresponding known direction with respect to said reference point; generating for each said source a signal from said received modulated radiation, said signal characterized by a modulation characteristic of said source; generating from each said signal a time of arrival signal, said time of arrival signal indicative of a time of reception of a first state of said modulation characteristic; estimating at said reception point from each said time of arrival signal a second state of said modulation characteristic, said second state of said modulation characteristic corresponding to said modulation characteristic at said reference point at said time of reception; and determining at least one navigational parameter at said reception point relative to said reference point from each said first state and each said second state; where said modulated radiation receiving step includes the step of receiving said modulated radiation from a plurality of said sources; and, where said navigational parameter determining step includes the steps of: establishing as said first modulation state for each of said sources a first phase corresponding to a phase of said modulation characteristic at said reception point and establishing as said second modulation state for each of said sources a second phase corresponding to said phase of said modulation characteristic at said reference point; calculating a plurality of phase differences for said reception point, each of said phase differences corresponding to a respective one of said plurality of sources and calculated as a difference between said first phase and said second phase; and determining from a relationship between said plurality of phase differences a location in three-dimensional space of said reception point relative to said reference point.