Defense contractor Northrop Grumman Corp. has put its navigation systems unit on the auction block and it could sell for as much as $1 billion, the Wall Street Journal reported on Monday, citing people familiar with the matter.

The report also said Wyle Laboratories Inc., a test and research firm majority owned by private equity firm Littlejohn & Co., was for sale and could garner a price under $400 million.

Representatives for Northrop and Wyle were not available to comment.