Navigation aid is a term used to describe any device or instrument that helps a person navigate. Synonyms for navigation aid include direction finder, compass, map, GPS, sextant, radar, beacon, marker, and guidepost. Direction finder and compass both refer to instruments that help locate or track a specific direction. Maps are a visual representation of the surrounding area, while GPS systems use satellite technology to determine location. Sextants are used in celestial navigation, and radar detects and tracks the position and movement of objects in the surrounding area. Beacons and markers are physical objects that indicate a specific location, and guideposts provide directional information along a path or route.