Navigation tools are essential for finding one's way in the world. Sonar (5 letters) is a tool used to detect objects underwater by emitting sound waves and measuring the time it takes for them to bounce back. MAP (3 letters) is a representation of a geographical area, often used to help people find their way around unfamiliar places. Astrolabe (9 letters) is an ancient navigation tool used to measure the altitude of stars and planets in order to determine one's location. RADAR (5 letters) is a tool used to detect objects on land or in the air by emitting radio waves and measuring the time it takes for them to bounce back. All of these tools are important for navigation and have been used for centuries.