The International Association of Marine Aids to Navigation and Lighthouse Authorities (1957) gathers marine aids to navigation authorities, manufacturers and consultants offering them the opportunity to compare and exchange their experiences and achievements. IALA's aim is to harmonize AtoNs worldwide and to ensure vessel movements are safe, expeditious, cost effective and harmless to the environment.
The International Civil Aviation Organization, a specialized UN agency with 190 Contracting States, is the global forum for civil aviation. ICAO works to achieve safe, secure and sustainable development of civil aviation.
The International Committee on GNSS is an informal body promoting cooperation on matters related to civil satellite-based positioning, navigation, timing, and value-added services, as well as compatibility and interoperability among the GNSS systems, while increasing their use to support sustainable development, particularly in the developing countries.
The International Hydrographic Organization (1921) is an intergovernmental consultative and technical organization supporting safety in navigation and the protection of the marine environment.
The International Maritime Organization is a specialized UN agency with 169 Member States and three Associate Members. IMO's main task is to develop and maintain a comprehensive regulatory framework for shipping, including safety, environmental concerns, legal matters, technical co-operation, maritime security and the efficiency of shipping.
The National Executive Committee for Space-Based Positioning, Navigation and Timing is a U.S. Government organization to advise and coordinate federal departments and agencies on matters concerning the GPS and related systems.
ESA's navipedia provides a comprehensive overview of satellite navigation systems and augmentation systems. You're welcome to join and add your knowledge.