Shadow based range and direction finder

A method of detecting a three-dimensional direction of a radiating object comprising:

• providing a first pair of planar detectors that detect incident radiation from the radiating object, the first pair of planar detectors situated in the same plane and bounded by at least one wall such that radiation from the radiating object incident at an angle with respect to the vertical along a first axis casts a shadow on one of the first pair of detectors and not the other;
• providing a second pair of planar detectors to detect incident radiation from the radiating object, the second pair of detectors situated alongside and in the same plane as the first pair of detectors, the second pair of planar detectors bounded by at least one wall such that radiation from the radiating object incident at an angle with respect to the vertical along a second axis casts a shadow on one of the second pair of detectors and not the other, the second axis perpendicular to the first axis;
• calculating a first two-dimensional direction of the radiating object in a plane defined by the first axis and the vertical based on a ratio of detected incident radiation on each of the first pair of detectors;
• calculating a second two-dimensional direction of the radiating object in a plane defined by the second axis and the vertical based on a ratio of detected incident radiation on each of the second pair of detectors;
• and
• calculating the three-dimensional direction of the radiating object based on the calculated first and second two-dimensional directions.

A method of detecting a three-dimensional position of a radiating object comprising:

• providing at least two three-dimensional direction detectors to detect the object's three-dimensional direction with respect to each direction detector, the direction detectors spaced a known distance apart along a baseline, each of the direction detectors comprising a set of coplanar radiation detectors with at least one wall arranged such that shadows cast by the wall leads to a change in incident radiation from the radiating object detected by the radiation detectors, each of the radiation detectors detecting the radiation incident thereon;
• calculating a first and a second two-dimensional direction from each set of coplanar radiation detectors to the radiating object based on a ratio of the detected incident radiation;
• calculating the object's three-dimensional directions from each three-dimensional direction detector based on the determined first and second two-dimensional directions;
• and
• calculating the object's distance from each of the three-dimensional direction detectors using triangulation based on the object's determined three-dimensional directions, the object's distance and three dimensional directions determining the object's three-dimensional position.