Boeing Defense, Space & Security has agreed to acquire Argon ST, a Fairfax, Va.-based developer of command, control, communications, computer, intelligence, surveillance and reconnaissance (C4ISR) systems, in an all-cash transaction the St. Louis-based aerospace contractor said June 30 will boost its presence in the C4ISR, cyber and intelligence markets. Boeing has agreed to pay $34.50 a share for the company, or roughly $775 million.

Argon ST, which generated $336 million in revenue in 2009, develops sensors and networks to exploit, analyze and deliver information for real-time situational awareness. Argon ST has approximately 1,000 employees and operating locations in Virginia, California, Michigan, Pennsylvania, Florida, Maryland and Texas.

Dennis Mullenburg, Boeing Defense, Space & Security’s president and chief executive officer, said acquiring Argon ST promises to “significantly accelerate our capabilities in sensors, communications technologies and information management.”

He said the merger follows two years of partnering with Argon ST on projects.

The agreement was unanimously approved by Argon ST’s board of directors, which intends to recommend the company’s stockholders tender their shares in the offer.

Boeing said it expects the transaction to close by the end of the third quarter 2010, assuming U.S. regulators sign off on the deal and a majority of the outstanding Argon ST shares are tendered.