Patent ID: 7663549

Claim:
An incoming direction estimation apparatus, comprising: three sensors that detect a signal emerging from a target, the three sensors being arranged to have a first distance d 0 between a first sensor that detects an intensity y 0 and a second sensor that detects an intensity y 1 among the three sensors, and a second distance d 1 between the second sensor and a third sensor that detects an intensity y 2 among the three sensors, wherein a 0 is a number equal to a ratio of d 0 and a wavelength λ of the signal, a 1 is a number equal to a ratio of d 1 and λ, and |a 1 −a 0 | is equal to or less than 1/4; and an estimation unit to estimate an incoming direction of the signal by performing mathematical operations using |a 1 −a 0 | which is related to relative distances between the three sensors, and ratios (y 2 /y 1 ) and (y 1 /y 0 ) which are related to intensities of the signal detected by the three sensors simultaneously.