WALTHAM, Mass., Jan. 5 -- Kollmorgen Corp. has been awarded a $17.5-million contract extension from the US Naval Sea Systems Command to provide a photonic mast production unit for the US Navy's second Virginia-class submarine. The new order is a follow-on option to an existing contract. Kollmorgen's Electro-Optical Division in Northampton, Mass. and Brattleboro, Vt. will conduct work on the new systems over the next two years. Each production unit comprises two masts, a workstation, and ancillary equipment. The photonic mast is a subsystem of the Navy submarine's command and control suite. The mast employs color and high-definition television, thermal imaging sensors, electronic image processing, and advanced displays in place of traditional periscope systems. Kollmorgen reported that the mast is currently being tested in a multi-year sea trial aboard the USS Annapolis, SSN 760.