These are the only two navigational systems with global coverage.

Their combined network had large global coverage during the 1980s and into the 1990s.

But there are countermeasures, and global coverage could be hard.

The systems includes both morning and afternoon satellites which provide global coverage four times daily.

The first is scheduled for completion in 2013, with full global coverage expected by the end of 2014.

The company has a global coverage of more than 4,000 employees with support in over 120 countries.

It plans new satellite launches in the next two years which will provide full global coverage.

The system, also known as Beidou-2, is expected to offer global coverage by 2020.

This will enable it to provide global coverage for the first time since 1995.

Together they provide twice-daily global coverage, and ensure that data for any region of the earth are no more than six hours old.