Patent ID: 8665135

Claim:
A radar device, comprising: an antenna configured to transmit an electromagnetic wave and to receive an echo signal from a target object while rotating in a horizontal plane such that a scan of the antenna represents one 360 degree rotation of the antenna; a display module configured to display the target object so as to correspond the echo signal to a position of the target object with respect to the antenna; a speed calculation module configured to calculate a relative velocity of the antenna and the target object; and a risk level detection module configured to detect a risk level of the target object based on the relative velocity of the target object calculated by the speed calculation module such that a risk level is detected for an echo signal received in a single scan of the antenna; a kind determination module configured to detect a signal kind of the echo signal based on echo signals received in two or more scans of the antenna; the risk level detection module being further configured to update the risk level of the target object based on the signal kind detected by the kind determination module and the relative velocity calculated by the speed calculation module; and wherein the signal kind includes at least a moving target object, and a sea surface reflection; said risk level detection module being further configured to detect a lower risk level for a target object determined to be a sea surface reflection, said lower risk level being lower than a risk level associated with a moving target object; the speed calculation module being further configured to calculate the relative velocity of the target object based on a change in phases of at least two of the echo signals received at different times; and the display module being further configured to control a display mode of the target object based on the risk level.