Boeing has completed an extensive series of radar system upgrades for Royal Saudi Air Force E-3A Airborne Warning and Control System (AWACS) aircraft, according to a company news release.

The upgrades under the Radar System Improvement Program (RSIP), which began as a joint U.S./NATO development program, include a new radar computer, a radar control maintenance panel, and electrical and mechanical software and hardware, according to Boeing. The RSIP kit, built by Northrop Grumman Electronic Systems, has also been installed on aircraft belonging to the U.S. Air Force, Royal Air Force, NATO, and French Armee de l’Air AWACS fleets.

The upgrade improves radar capabilities, including the system’s electronic countermeasures, sensitivity, and the range at which targets can be acquired and tracked. It also enhances the system’s reliability, maintainability, and availability through the use of more modern components and digital off-the-shelf computers.

“The AWACS’s main mission is to provide real-time situation awareness, and our teams have stayed true to that mission,” said Keith Burns, Saudi AWACS programs manager for Boeing. “The modernized software, multiple radar nodes and overall enhanced operation make this is the most significant upgrade to the AWACS radar since it was developed in the 1970s.”

After Boeing engineers and technicians upgraded the first aircraft in the United States, the remaining aircraft were modified at Alsalam Aerospace Industries in Riyadh, Saudi Arabia, with support of Boeing engineers, technicians and a test and evaluation team.

The Reagan administration’s 1983 decision to sell the aircraft to Saudi Arabia was controversial at the time. Boeing delivered the kingdom’s five AWACS aircraft between June 1986 and September 1987.

Today Saudi Arabia is the fourth largest operator of the E-3 AWACS, after the U.S. Air Force, NATO, and the Royal Air Force.