A method and apparatus for photogrammetrically determining a six degree of freedom spatial relationship between a first object and a second object is disclosed. In one embodiment, the method comprises photogrammetrically determining a first orientation of the first object relative to the second object, photogrammetrically determining a second orientation of the second object relative to the first object, and determining the six degree of freedom spatial relationship between the first object and the second object from the photogrammetrically determined first orientation of the first object relative to the second object and the photogrammetrically determined second orientation of the second object relative to the first object.