Method of operating a directed emitter/sensor for electromagnetic tracking in augmented reality systems

1. A method of operating a head mounted augmented reality display system, the method comprising:

producing an electromagnetic field using an electromagnetic emitter, positioned in a handheld controller;

reflecting the electromagnetic field using a first electromagnetic reflector, positioned adjacent to the electromagnetic emitter, to form a modified electromagnetic field, wherein:

the first electromagnetic reflector defines a first coordinate space and a first corner vertex of a first cube lies at the origin of the first coordinate space; and

the electromagnetic emitter is positioned along a line directed at point (1,1,1) in the first coordinate space;

reflecting a portion of the modified electromagnetic field using a second electromagnetic reflector positioned in a headset; and

detecting the reflected portion of the modified electromagnetic field by an electromagnetic sensor positioned adjacent to the second electromagnetic reflector.

2. The method of claim 1 wherein the electromagnetic field is characterized by an initial full width half maximum and the modified electromagnetic field is characterized by a modified full width half maximum less than the initial full width half maximum.

3. The method of claim 2 wherein the modified electromagnetic field is characterized by a higher field intensity at a lobe center than the electromagnetic field.

4. The method of claim 1 wherein a sensor housing is mounted on a right temple of the headset.

5. The method of claim 4 wherein the sensor housing is positioned such that the second electromagnetic reflector is directed at a region of interest defined by an expected location of a higher intensity lobe of a modified electromagnetic field.

6. The method of claim 1 wherein the modified electromagnetic field has a lobe lying along the line directed at point (1,1,1) in the first coordinate space.

7. The method of claim 1 wherein each of the first electromagnetic reflector and the second electromagnetic reflector includes three first reflective elements and three second reflective elements, respectively.

8. The method of claim 7 wherein the three second reflective elements define a quadrant of a second coordinate space in which the electromagnetic emitter is positioned.

9. The method of claim 1 wherein the second electromagnetic reflector defines a second coordinate space and a second corner vertex of a second cube lies at the origin of the second coordinate space.

10. The method of claim 1 , further comprising using a controller to control timing of electromagnetic emission and sensing and digitally compute a position and orientation of the electromagnetic emitter and the electromagnetic sensor based on the modified electromagnetic field.