A warning system is a system that provides alerts or warnings to individuals or groups of people in order to protect them from potential danger. One example of a warning system is RADAR, which is an acronym for Radio Detection and Ranging. RADAR is a system that uses radio waves to detect objects and measure their distance, speed, and direction. It is used by the military, air traffic control, and weather forecasting to detect and track objects such as aircraft, ships, and storms.