The EU's Galileo satellite navigation system has been knocked offline for four days following a ground-based technical incident.

Most of the satellites in the Galileo constellation have suffered a service outage since Friday as the official status of all its crafts as currently 'Not Usable'.

Two of the 26 are said to be 'testing' while two others have long been out of service due to unrelated issues.

It is believed the ability to locate and help people in distress situations is unaffected.

Experts are working to restore operations of the multibillion euro programme, the European Global Navigation Satellite Systems Agency (GSA) said.

The system is provided for free and is used by private firms, government agencies, academics and the tech sector.

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The EU's Galileo satellite navigation system has been down for four days as a result of a technical incident on the ground. The majority of satellites in the Galileo constellation have suffered a service outage (stock)

Issues have persisted the duration of the weekend and it means satellites cannot currently give locations or times to smartphones or other devices.

The majority of popular handsets in use around Europe are reliant on Galileo - including all iPhones released since 2017.

It is still in its earl stages as a project and is therefore not trusted with vital systems, with crucial services using other means.

It operates independently of the US system as well as not relying on Russia's GLONASS or China's Beidou networks.

Galileo began testing in December 2016 as an alternative to the US-made Global Positioning System (GPS), designed to provide an exact location to commercial and government customers, with a full deployment expected in 2020.

Experts are working to restore operations of the multibillion euro programme, the European Global Navigation Satellite Systems Agency (GSA) said on Sunday. The system is provided under both free and commercial ventures and is used by both private firms, government agencies, academics and the tech sector

The cause of the technical incident is identified and recovery actions are implemented to ensure that the nominal service is resumed as soon as possible while safeguarding quality of the services,' the GSA said.

In November, Britain gave up on efforts to gain access to the EU's Galileo satellite navigation system for defence and critical national infrastructure purposes, after being frozen out by Brussels because of Brexit.

It is unclear whether the UK will get back the £1.2 billion it sank into Galileo.

Instead, it is aiming to build its own Global Navigation Satellite System, at a cost estimated by independent experts at £3 billion to £5 billion.