* Anteon International, a Fairfax government-technology contractor, said it won the right to compete for up to $348 million worth of work refurbishing and upgrading computer systems on ships in the Navy's Atlantic fleet. The work is mainly limited to the electronics that control weapons and the networks that receive and organize intelligence data. Under the 10-year contract, Anteon can bid for specific jobs against Raytheon, whose potential business under its contract is capped at $378 million. Anteon, with sales of $1 billion last year, saw profit grow 50 percent, to $13.3 million, in the first quarter of the year as more federal agencies tapped it to overhaul aging computers. The Navy win announced yesterday reflects the mid-size company's efforts to bid on more contracts worth at least $100 million, said spokesman Dennis J. Kelly. The company says it is expecting decisions on 10 more contracts valued at more than $100 million by the end of the year.

* Sensytech and Argon Engineering Associates agreed to merge in an all-stock transaction approved by both companies' boards. Shareholders of Fairfax-based Argon will receive two shares of Sensytech stock for every share of Argon. Argon shareholders will own 66 percent of the combined company. The merger is scheduled to close in September. Argon designs and develops communication systems that search, identify and capture signals. Newington-based Sensytech designs and manufactures electronic surveillance, communication and imaging systems. Argon's fiscal 2004 revenue was twice Sensytech's. The deal must still be approved by shareholders. Sensytech stock fell 17 cents, to $20.77.

* Essex Corp., a Columbia defense contractor, agreed to acquire Performance Group Inc. of Fredericksburg. Terms were not disclosed. The deal is expected to close within several weeks. PGI is a privately owned provider of services in geographic information systems and imagery processing and analysis. Essex stock fell 18 cents, to $8.05.

Compiled from reports by Washington Post staff writers, Business Wire and PR Newswire.