Patent ID: 8324517
Filing Date: 2012-12-04
Classification: G06F

Abstract:
1. An apparatus comprising a receiver comprising: a base having a planar base surface; first and second acoustical sensors that detect an acoustical signal emitted by a moveable signal source, said first and second acoustical sensors being mounted on said base and separated from one another; a EM detector that detects an EM signal that is synchronized with said acoustical signal; and a controller that measures the difference in time of detection between said first EM signal and said acoustical signals detected by said first and second acoustical sensors; wherein said first and second acoustical sensors each comprise: a detector that generates an electrical signal in response to an acoustical signal in a predetermined frequency range; and a housing surrounding said detector, said housing having a housing aperture defined in relation to a base surface, said housing aperture having a width in a first plane that is perpendicular to said base surface, said width being less than the wavelength of said acoustical signal divided by 6.28 and said housing aperture having a height in a second plane that is perpendicular to said base surface and said first plane, said height being substantially equal to an integer multiple of a wavelength of an interfering acoustical signal.