The United Kingdom Global Navigation Satellite System (UK GNSS) was a United Kingdom Space Agency (UKSA) research programme which, between May 2018 and September 2020, developed outline proposals for a United Kingdom (UK) owned and operated conventional satellite navigation system, as a British alternative to the European Union (EU) owned and operated Galileo Global Navigation Satellite System.

The main reason was to provide a national and independent system, to ensure UK security following its withdrawal from the EU as a result of Brexit.

With the now universal reliance on the output provided by satellite navigation systems by many aspects of everyday life, in both private and commercial sectors, along with critical uses by military, maritime, and emergency services, continued and reliable access to such navigation systems is vital for the United Kingdom.

An earlier study by the UK Government warned that sustained disruption to a reliable satellite navigation could cost the British economy £1 billion per day.

[4] The United Kingdom Global Navigation Satellite System was first discussed by the UK Government in May 2018,[4][5] after the European Union told the United Kingdom that it would no longer have full access to,[3] nor be able to use the encrypted secure component (known as the Public Regulated Service, which is only accessible to the military, emergency services, and government agencies) of the Galileo system,[1][2][6] the European equivalent of the United States of America owned and operated Global Positioning System (GPS), originally known as Navstar GPS.