GEC Sensors was the part of GEC involved in the design and manufacture of electro-optic equipment. Devices such as thermal imaging systems used in FLIR such as the Thermal Imaging and Cueing (TICM) ‘Atlantic’ pod are a major part of the business.
Marconi Electro-Optical Systems Division was operating at Basildon in 1969 and suffered the usual multiplicity of name changes. Over some period prior to 1988 the company at Basildon was named GEC Avionics and previously Marconi Avionics and in 1993 GEC Sensors, GEC Ferranti, GEC Avionics and GEC-Marconi Aerospace were all brought together under the GEC-Marconi Avionics brand. With the merger into BAE Systems the site became part of BAE Systems Avionics which was the avionics unit of BAE Systems until 2005, at which time it was transferred to SELEX Sensors and Airborne Systems S.p.A (initially 75% Finmeccanica and 25% BAE Systems, but since March 2007 fully owned by Finmeccanica) and was renamed SELEX Sensors and Airborne Systems Limited. The company became SELEX Galileo in 2008 and since January 2013 (following a merger with other Finmeccanica defence electronics companies SELEX Sistemi Integrati and Selex Elsag), has traded as Selex ES merged into Leonardo-Finmeccanica's (formerly Finmeccanica) land and naval defence electronics division since 2016.