地球是圆的雷达是现代军舰侦测目标的主要手段。但是,雷达就像人的眼睛,而眼睛遵循的规律是:站得高才看得远!所以,处在海平面的军舰,它能探测到的海面目标是有限的,因为地球是圆的。这意味着80千米以外的海上目标(如航母战斗群)处于地平线以下,你看不见80千米外任何海面目标,那里是雷达的盲区。为了探测到更远的目标,唯一的办法就是把军舰上的雷达放得很高,所以有些军舰甚至是把 Earth is a round radar is the main means of detection of modern warships. However, the radar is like a human eye, and the law the eye observes is: standing tall and far away! Therefore, at sea level warships, it can detect the sea targets are limited, because the earth is round. This means that offshore targets 80 kilometers away (such as aircraft carrier battle groups) are below the horizon and you can not see any sea targets 80 kilometers away, which is the blind spot of the radar. The only way to detect farther targets is to put the radar on the warships high, so even some warships