Aids to Navigation (AtoN)

Aids to navigation (AtoN) are the fixed and floating marks established to help a mariner determine position, keep to a safe route, and warn of dangers: buoys, beacons, lighthouses, leading lights, fog signals, racons, and AIS AtoN. IALA defines and recommends the standards, and SOLAS Chapter V Regulation 13 requires governments to provide AtoN as traffic justifies. Each carries a character (shape, color, topmark, light rhythm, sound) that the chart and the light list describe in a fixed code, so the meaning is read the same way worldwide. AtoN supplement, never replace, the ship’s own fixing by GNSS, radar, and visual bearings.