Air-traffic controllers use radar to monitor and direct the movements of aircraft in order to prevent collisions. With radar systems controllers are also able to help guide pilots to safe landings when visibility is poor. Many ships are equipped with simple radar units for coastline navigation. In some ports large radar surveillance sets are used to monitor harbor traffic conditions and assist shipping. Radar is used in astronomy to make more accurate distance measurements than optical methods can provide and as a tool in mapping planetary and satellite surface features.
Weather forecasters use radar to locate and track approaching storms.
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