With the increase of global satellite navigation systems (GNSS) in a limited number of frequency bands, the current spectrum dedicated to satellite navigation encounters congestion. A possible path to keep modernizing the different GNSS is to find new frequency bands where a satellite radio-navigation service (RNSS) could be provided. This article takes a regulatory approach to identify potential candidate bands, which are then reviewed in detail to assess their usability for a new RNSS deployment. The results of this analysis are: (1) there exist spaces in the spectrum where a RNSS allocation exists or could be added. For example, the option consisting in adding another RNSS allocation into aeronautical radio-navigation service (ARNS) bands. However, such allocation change is not planned and would require important commitment from administrations and long negotiations with the civil aviation community; (2) the use of telecommunication signals of opportunity coming from an hybrid satellite-terrestrial network of emitters. Among these solutions, some would permit to combine navigation and telecommunication services, offering a huge opportunity for mass market application.