Marine Radar

Marine radar is an X band or S band radar system carried aboard ships to detect other vessels and land hazards, giving their bearing and distance for collision avoidance and navigation at sea. A rotating antenna sweeps microwave pulses across the surrounding water, and the returning echoes are displayed so the operator can see the position of other ships and obstacles; S band performs better in poor weather while X band gives sharper definition in clear conditions, and most merchant ships carry at least one of each type for complementary coverage. Radar is one of the means recognized under the International Regulations for Preventing Collisions at Sea for keeping a proper lookout, and international maritime safety rules require it aboard oceangoing ships.