A radar including a target measurement component, a differential velocity calculator and an overall velocity determination portion. The target measurement component transmits and receives an electromagnetic wave over a detection range repeatedly at measurement intervals to measure a position of a target in the detection range and measure a Doppler velocity of the target based on a Doppler shift of the electromagnetic wave reflected from the target. The differential velocity calculator determines a differential velocity of the target based on a change in position of the target during consecutive measurement intervals. The overall velocity determination portion determines a current overall velocity by calculating a weighted average of the Doppler velocity, the differential velocity, and a previously determined overall velocity.