Patent ID: 7088286

Claim:
An apparatus for detecting a direction of a target to be detected which resides in a spatial area to be tracked using radio tracking, the apparatus comprising: a plurality of transmission/reception channels causing a difference between phases of two reception signals to be received through two adjacent transmission/reception channels of the transmission/reception channels, the transmission/reception channels including a transmission antenna transmitting radio waves to cover the entire spatial area in response to a transmission signal to be given, a reception antenna receiving reflected radio waves coming from the spatial area so as to produce the two reception signals in accordance with the reflected radio waves, and a receiver processing the two reception signals into processed signals; a direction calculating device calculating the direction of the target based on the phase difference in the reception signals on the assumption that the phase difference is within a range of −π to +π[rad]; a range determining device determining that the target currently exists in one of a plurality of azimuthal angle ranges respectively corresponding to ranges sectioned in the spatial area between (2m−1)π to (2m+1)π [rad] (where m is an integer); and a direction correcting device correcting the direction calculated by the direction calculating device according to a result determined by the range determining device.