Positioning system and method

A six dimensional (6D) positioning system, comprising:

• a set of at least two light source modules, each light source module comprising:
• a light source;
• communication means for communicating with other light source modules;
• a clock;
• fixation means for fixing the module on a support
• at least one shadow sensor configured to sense shadows cast on the shadow sensor by light emitted from the light sources of the light source modules, said shadow sensor comprising an imager;
• and
• a processor;
• wherein:
• the maximum distance between the light sources is larger than fifty times a width or a height of said imager, and
• the processor is configured to:
• sync a shadow sensing with a pulsing of the light sources;
• distinguish between the sensed shadows from each of the light sources;
• determine two dimensional positions corresponding to each of the light sources based on the sensed shadows;
• and
• compute a six dimensional (6D) position of the at least one shadow sensor with respect to the light sources based on the determined 2D positions.

A method for estimating a six dimensional (6D) position, of a shadow sensor with respect to a plurality of light sources, the shadow sensor being configured to sense shadows cast on the shadow sensor by light emitted from the light sources, said shadow sensor comprising an imager, the maximum distance between any of said light sources being larger than fifty times a width or a height of said imager, the method comprising:

• sync a shadow sensing with a pulsing of the light sources;
• distinguish between the sensed shadows from each of the light sources;
• determine two dimensional (2D) positions corresponding to each of the light sources based on the sensed shadows;
• compute a 6D position of the at least one shadow sensor with respect to the light sources based on the determined 2D positions;
• sense shadows cast on the shadow sensor by light emitted from the light sources, wherein at least two light sources are at a fixed position with respect to each other;
• record a projection of at least six points from a fixed location, each point corresponding to the three dimensional (3D) position in space of a light source, a projection of a point being recorded as the two dimensional (2D) position of the sensed shadow cast by said light source on said shadow sensor;
• repeat said recording and computing steps from a different fixed location, so as to obtain N recordings comprising each the projection of a set of the same P light sources, N and P being integer numbers satisfying a predetermined constraint;
• compute the three dimensional (3D) relative position of every light source within a common reference frame, said position being defined up to a scale factor;
• and
• scale every computed three dimensional (3D) relative position so that the computed three dimensional (3D) relative position of said at least two light sources matches said known fixed position.