The acronym ILS (Instrument Landing System) refers to an aviation technology that assists pilots with instrument-based approaches to runway landings. Some synonyms for ILS include landing aids, navigational aids, runway guidance systems, and avionics technologies. ILS is often the standard system used for precision approach landings, but other similar technologies exist such as Microwave Landing System (MLS), GNSS Landing System (GLS), and RNAV (Area Navigation). These systems work together to assist pilots in safe landings in varying weather and visibility conditions. As technology continues to evolve, so do the tools available to aid pilots in landing their aircrafts.