Defense contractor BAE Systems won a $146 million contract for work on the USS Gettysburg, part of a class of guided-missile cruisers whose weapons and computer systems are undergoing upgrades to ensure they reach their 35-year service life.

Work on the Gettysburg, which will be performed at London-based BAE's shipyard in Norfolk, Va., is scheduled for completion by 2020, and includes maintenance, modernization and repair, the U.S. Department of Defense said in a statement on Monday. The contract includes options that could bring its total value to $151.3 million.

Built by Bath Iron Works, Gettysburg was commissioned in 1991 under former President George H.W. Bush. It belongs to the Ticonderoga class, which was first deployed in 1983 and uses Aegis technology to track aerial targets. Carrying Tomahawk missiles, the vessels can support carrier strike groups as well as conduct independent operations.

The modernization program for the cruisers includes updates to computer and display equipment as well as electrical and mechanical systems. Weapons and sensor sets will be modified to improve submarine-combat capabilities, the Navy said, and electro-optical systems will be added that can monitor the ship's surroundings without radar emissions.

Improvements to Gettysburg, under a schedule authorized in Congress's 2015 defense spending bill, come as President Trump works to upgrade U.S. military capabilities more broadly. A two-year agreement ratified by lawmakers in March raised the cap for defense spending to $700 billion for fiscal 2018, which ends Sept. 30, and to $716 billion for 2019.