The US Navy awarded the Boeing company a $152 million contract to complete the design, development, integration, and testing of the Infra-Red Search Track (IRST) system for the F/A-18E/F Block III aircraft, the latest variant of the Super Hornet. A few days later the company received another $208 million contract to integrate and produce Lockheed Martin’s Legion Pod IRST for the US Air Force F-15C/D fleet.
The new Block II IRST will replace the Block I system which did not meet the Navy’s requirements. This “see first, strike first” capability empowers pilots with greater reaction time, improving survivability. Development and testing are expected to conclude in 2021, in time for expected Super Hornet Block III deliveries. The first part of this program was an $89 million order awarded in June 2017. In October, the sensor’s manufacturer, Lockheed Martin was awarded $100 to upgrade the IRST21 sensor for the new Block II standard.
The IRST will enable the Navy fighters to target adversaries beyond visual and radar range, and enhance survivability in radar denied environment, operate against existing and emerging air threats. While the US services have yet to embrace IRST technology, some of NATO air forces, as well as Russia and China are employing such systems for many years, as well as Singapore and South Korea, that integrated the US IRST21 on their F-15s. The introduction of high performance, networked IRST utilized as a passive radar rekindled the interest in the technology in the USA.
IRST relies on the thermal signature emitted by the target, tracked from a very long distance. While these tracks are affected by clouds and humidity, the high sensitivity of the Long Wave sensors is optimized for operations even under adverse visibility conditions. The Navy intends to produce a total of 170 IRST systems, produce 152 new Block II systems and retrofit 18 Block I systems currently used for testing.
The IRST consists of a passive long-wave infrared (LWIR) receiver, a signal processor, inertial measurement unit and environmental control unit packed into a section of a fuel tank attached to the belly of the Super Hornet. The Block I IRST of this type used components from the F-15K/SG which are based on the system first used with the F-14A Tomcat since the 1980s. At the time those systems were used to augment the radar and enable the Navy fighters to better identify targets and engage them at extended range. An improved version of the original IRST21 system is designed as a long-range counter-stealth sensor.
The IRST will be part of an avionics upgrade that will prepare the Super Hornet to fight modern adversaries. Other elements of that upgrade include the Distributed Targeting Processor – Networked computer (DTP-N), a new, powerful processor that will increase the capability to process multiple tracks, from on board and remote sources, in real time. Remote tracks will be delivered over a new, high speed data link known as the Tactical Targeting Network Technology (TTNT), that enable several Super Hornets flying a loose formation to share many tracks picked by their IRSTs, to passively ‘fix’, geolocate, and determine the range and heading of each target, just like a radar – something a single IRST cannot do.