1.   Another concern centers on focal plane arrays, widely used sensors that help guide missiles, tanks and other military systems.

2.   Besides missiles, regulators have been concerned with reduced competition for systems used to guide missiles, in this case focal plane arrays and electro-optical systems.

3.   Hughes is the leading manufacturer of focal plane arrays, and Raytheon is the second-largest.

4.   The other two issues are ground electro-optical systems and focal plane arrays, the person familiar with the review said.