an Entity references as follows:
Aeronautical radionavigation service (short: ARNS) is – according to Article 1.46 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as "A radionavigation service intended for the benefit and for the safe operation of aircraft." This service is a so-called safety-of-life service, must be protected against interference, and is an essential part of navigation.