Direction detection device, method of acquiring intensity difference table, direction detection method, and computer-readable storage medium

A direction of arrival detection device 40 including antennas 5 that receive a received wave, an intensity difference imparting unit that imparts intensity differences different depending on the received-wave arrival direction. The intensity difference imparting unit preferably being a radome (6, fig 1) with physical features and/or structure which creates the intensity difference. A storage unit 11 that stores an intensity difference table T1 in which the intensity difference between two of the antennas is associated with the received-wave arrival direction. A detector 10 detects an intensity difference between the two antennas and a phase difference between the two antennas, of the received wave. An extractor 13b extracts, from the table, a received-wave arrival direction corresponding to the detected intensity difference. A calculation unit that calculates a received-wave arrival direction corresponding to the detected phase difference, or alternatively the phase difference related to arrival direction is also stored in a table T2 and extracted by a second extractor 13a. A comparator 14 that compares the extracted received-wave arrival direction with the calculated received-wave arrival direction to acquire a matched received-wave arrival direction.