Northrop Grumman ( NOC) said its fourth-quarter earnings from continuing operations rose 37% from the same period the previous year, and the defense-systems maker took its profit guidance higher for 2007.The company had a continuing operations profit of $457 million, or $1.29 a share, for the fourth quarter, up from $334 million and 93 cents a share last year. Analysts were looking for $1.26 in the most recent quarter. Net income for the quarter was $453 million, or $1.28 a share. Sales increased 5% to $8 billion, in line with estimates. Looking ahead, Northrop is anticipating full-year sales of $31 billion to $32 billion, with earnings from continuing operations of $4.80 to $5.05 a share. Wall Street is calling for earnings of $4.85 and sales of $31.8 billion.