Patent ID: 8411258

Claim:
A method for determining a coordinate of an object, said method comprising: receiving, at a positioning receiver system coupled to said object, calibration data from a positioning transmitter system associated with each of at least four light sources; receiving, at said positioning receiver system, a modulated light signal transmitted from each of said at least four light sources of said positioning transmitter system, each of said modulated light signals having a modulation frequency and wherein each of said at least four light sources emit light having a wavelength in the visible light spectrum; determining, at said positioning receiver system, at least four phase difference of arrival (PDOA) pairs based on each of said at least four modulated light signals; determining, at said positioning receiver system, at least four phase corrected PDOA pairs based, at least in part, on said calibration data and said at least four PDOA pairs; determining, at said positioning receiver system, at least four linear distance differences based on said at least four phase corrected PDOA pairs; and determining, at said positioning receiver system, said coordinate of said object based on said at least four linear distance differences and said calibration data.