Harlow, one of Raytheon Systems Limited's principal design and manufacturing facilities, has an international reputation in a number of high technology areas. These include Air Traffic Management Systems, identification systems and jam resistant navigation systems. The site is also heavily involved in RSL's ISR and Network Enabled Capability activities.

Harlow 's advances in secondary radar and IFF systems have resulted in exports to 40 countries around the world and with equipment in operation with the armed forces of some 30 nations. RSL's role as prime contractor for the Ministry of Defence's SIFF (Successor Identification Friend or Foe) programme for the UK 's armed forces builds on Harlow 's strength as a centre of excellence for IFF technology.

RSL at Harlow undertakes R&D and design as well as manufacturing and support work. Recent successes include the development of a superior ADS-B system for future air traffic management and a contract to provide digital jam resistant GPS systems to the US Air Force.

The management of other major RSL programmes, such as ASTOR (Airborne Stand-Off Radar) and PGB (Precision Guided Bomb), is also handled out of the Harlow facility.

Harlow employs some 600 people, most of whom are high grade engineers and skilled electronics technicians. The site occupies approximately 215,000 sq. ft.