The first USMC Harrier II was the AV-8B, a daytime strike fighter. In 1984 development of the AV-8B(NA) “Night Attack” Harriet II began with the addition of a NAVFLIR (Navigation Forward-Looking Infrared) camera in the nose along with night vision goggles. New MFDs (Multi Function Displays) were added as well as an improved HUD, color CRT display and complete heads-down capability. This version of the Harrier also received additional counter-measure dispensers and Rolls-Royce Pegasus 11-61 (F402-RR-408) vectored-thrust turbofan engine.
The AV-8B II + is the second generation of Harriers. Using its VSTOL (Vertical and Short Take Off Landing) abilities the Harrier is capable of using almost any surface to attack and destroy air or ground targets. Armed with conventional or specific weapons the AV-8B II + can be used in offensive or defensive roles. Now with air-borne radar the AV-8B II + can deliver its ordnance day or night. The AV-8B II + can be air refueled allowing it to be deployed for extended periods.
The GR.7 series is part of the second generation of Harriers and replaced the older GR.3. This variant is quite similar to the American designed AV-8B but is built under license and equipped with RAF specific navigation and defense systems and added under-wing pylons. The GR.7 is capable of carrying twice the load of the GR.3 or the same load twice as far. The GR.7 first flew in 1989 and entered service in 1990. Of the 96 GR.7 Harriers belonging to the RAF 62 originally were GR.5s that were upgraded to GR.7s.
The Harrier GR.9 an upgrade to the GR.7 that involves avionics and weapons. The Integrated Weapons Program (IWP) enables the aircraft to carry the new smart weapons as well as INS and GPS. Now capable of carrying the Brimstone, Maverick, Paveway III LGB and the Paveway IV PGB missiles the GR.9 will also receive a Sniper targeting pods.
The GR.9 Harrier came into service in October 2006 and is a very updated improvement on the GR.7. The GR.9 is capable of a wider range of advanced precision weaponry, new communications along with upgraded airframes.