The Airborne Warning and Control System (AWACS) fleet has served as a surveillance aircraft for the North Atlantic Treaty Association (NATO) for close to 20 years. The Boeing E-3 Sentry (B707 airframe) with its giant wafer-shaped radar antenna towering just in front of its tail, played a major role during Desert Storm and, more recently, supported peacekeeping operations in Kosovo. Now, as part of NATO’s mid-term modernization program, AWACS is being upgraded in preparation for 20 more years of operation.
Nine Enhancements
Boeing manages the upgrade program, which includes installing improved navigation, communications, mission computing, and target identification and tracking for NATO’s 17-aircraft E-3 AWACS fleet. Boeing describes it as a "single block" upgrade, integrating nine enhancements.
The first production AWACS aircraft was delivered to NATO in 1982 and the last in 1985. Interim modernization programs had new color displays, UHF anti-jam procedures, and a version of the Joint Tactical Information Distribution System (JTIDS) installed. Under a separate contract, the radar system improvement program (RSIP) was designed to increase the sensitivity of the E-3’s pulse Doppler radar (see sidebar on page 29).
In addition to NATO’s 17 E-3s, the U.S. Air Force operates 33 AWACS aircraft; the United Kingdom, seven; Saudi Arabia, five; and France, four, for a total of 66. (Japan has four new Boeing 767 AWACS aircraft.)
AWACS, with a 360� view of the horizon and ability to track air and sea targets simultaneously, fills the need of both airborne surveillance and command-and-control communications for NATO and maritime forces.
The Timetable
The first E-3 to be upgraded was taken from NATO’s main operating base at Geilenkirken, Germany, to Boeing’s Wichita, Kan., facility in November 1999. It entered modification under a $450-million engineering, manufacturing and development (EMD) contract received two years prior. Boeing expects modification work on this aircraft, called N-1, to run through April in Wichita. N-1 then will be flown to Seattle, Wash., in late spring where installation and check out will lead to qualification flight testing, which is scheduled to begin in August and continue until spring 2001, according to Tim White, deputy program manager in Boeing’s Information & Surveillance Systems unit.
After that, NATO will take back custody of N-1 to begin its initial operational test and evaluation (IOT&E). The IOT&E phase will lead to a production and retrofit (PAR) contract—expected to begin in late 2001 and extend for three years.
The fleet will be retrofitted incrementally to ensure that NATO has sufficient operational aircraft to meet its mission needs. Meanwhile, Boeing expects a long-lead production contract to be authorized by the end of this year.
In the program’s PAR phase, DaimlerChrysler of Manching, Germany, will modify the entire fleet. Currently, five DaimlerChrysler representatives work "over the shoulder" with the Boeing team in Wichita to ensure a smooth transition. The prime contractor integrator during the program’s EMD and PAR phases, Boeing will manage procurement, logistics, documentation, and training out of Seattle and be responsible for system integration and delivery, and provide software support and validation.
Management of the AWACS upgrade program is not as straightforward as one might initially believe. For example, Boeing is the prime contractor to an agency of NATO, called NAPMA, or NATO AEW (airborne early warning) Program Management Agency, with offices in Brunssum, Netherlands. And the contract is administered by the U.S. Air Force’s Electronics Systems Division, at Hanscom AFB, Mass. The first-tier subcontractors are from NATO member countries.
Committed to COTS
White cites the emphasis on integrating commercial off-the-shelf (COTS) hardware and software into the AWACS systems. "We’re recoding and integrating our mission software using an ‘object-oriented’ development approach. In the past, we used the traditional, functionally-oriented software, common to all aerospace companies," he explains. "We are changing completely to a more interface-related approach. We’re also re-hosting the software; it will be written in Ada [computer programming] language."
White maintains that open-architecture software using COTS technology for the AWACS aircraft will reduce the cost of both development and maintenance and support.
N-1 flight tests will be conducted concurrently with system-level testing at two Boeing laboratories in Seattle. One facility, the NATO Avionics Integration Laboratory (NAIL) contains a complete aircraft shipset of equipment, with 14 consoles, computers, communications and other equipment. It is designed to support engineering test and evaluation (ET&E) activities through this spring and continuing during the summer’s flight tests.
"Things we can run and qualify on the ground, we’ll do in the NAIL," says White. The other Seattle test center, the NATO Development Laboratory (NDL), contains AWACS subsets, where hardware and software integration is being conducted at the system level.
"Some 20 NATO representatives are collocated at the NDL, the bulk of them mission operators from the NATO fleet," White adds. "They give us real-time feedback on the situation display consoles and the human-machine interface we are developing.
"We use that operator feedback and data from our own mission computing program in our interface description documents and other software interfaces with both Konsburg, of Norway, who does our situation console software, as well as with our other contractors," says the deputy program manager. "It’s important to get real-time feedback from the operator during development to transition smoothly to the IOT&E phase."
Leading the Fleet
NATO leads the AWACS fleet with its mid-term modernization program upgrades, according to White, who says he believes other AWACS customers will add some of these upgrades.
"Many of these groups of nine enhancements…are applicable to each of the other fleets," he continues. "In particular, the human-machine interface and the tracking and identification software are very transportable into several other fleets."
White also believes that some of the hardware and software architecture enhancements for the NATO program will have broader application for other Boeing programs beyond the AWACS fleet.
NATO Mid-Term Upgrade—Up Close
Navigation
Boeing is upgrading the AWACS navigation system by replacing the Northrop Grumman Omega system (upgraded by GPS) with a GPS receiver with imbedded inertial navigation (INS), integrated with the flight management system (FMS). Litton provides the embedded GPS/INS, Rockwell Collins the GPS control unit, and Honeywell the standard airborne data computer.
Communication
Boeing is installing a digital communications system to improve crew access to radio links and provide automatic communications and display data record and replay. Automatic digital communications switching will provide the ability to assign, reassign and manage the extensive communications suite.
Boeing will integrate satellite communications into the mission system and add two integrated UHF satcom terminals. The wide-spectrum VHF radios, in both AM and FM, will support broader interoperability with other aircraft, as well as with European nations’ air and ground forces. Thomson (Belgium) provides the digital communications systems, while Marconi Communications (Italy) furnishes the VHF radios and satcom subsystem.
Identification-friend-or-foe (IFF) Mode S transponder and IFF interrogator capabilities also are being added to provide improved identification capability with emerging international air traffic control systems. Italy’s Marconi Communication provides the interrogator and DaimlerChrysler (Germany) the transponder.
Mission Computing
In replacing the mission computing system, Boeing’s Tim White says, "We’re going from the traditional central computing to a much more distributed software infrastructure with imbedded software in most of our significant LRUs [line replaceable units].
"Likewise, in our IFF and communications system software, much of the development has been to forge software interfaces between the main computing programs that run on the mission computer and those programs that run on what we call a multisensor integration computer," White adds. "Those are what run our human-machine interface programs on our situation display consoles."
The AWACS upgrade program also adds five additional flat-panel situation display consoles in the E-3 cabin area, increasing the complement to 14 on each aircraft.
Multisensor integration will merge all information (from the main radar and IFF returns, etc.) about a specific target into a single computer track, which shows the target’s direction and speed.
This, says White, improves the reliability and accuracy of the tracking process and target identification. DaimlerChrysler is both performing the computer’s multisensor integration and developing the tracking and identification software.
"A combination of the multisensor integration, the Windows-type displays in the human-machine interface and the additional consoles reduce crew workload and substantially increase operator effectiveness and efficiency," White says.
Computing Devices of Canada provides the AWACS aircraft’s situation display consoles, and Kongsberg Defence Systems (Norway) the situation console computer program software.
Current upgrade plans call for use of a fiber-optic-based, local area network (LAN) to handle high-speed data rates with a number of interfaces throughout the aircraft.
While suppliers provide the interfaces, Boeing is in charge of the installation and uses the fiber-optic cables from the same Huntington Beach, Calif., facility that provides them for the Space Station.
A Cockpit Largely Unchanged
Except for the navigation improvements, a cockpit upgrade is not part of NATO’s E-3 AWACS mid-term modernization program. The aircraft currently operate with analog dials and instruments.
"We’re not upgrading the cockpit in the sense of a complete re-do, like a glass cockpit," says deputy program manager Tim White. "We’re touching those elements or subsystems in the cockpit that are inherent in those subsystems that are being modified.
"For example, AWACS is getting a complete upgrade of its communications system," he adds. "On the [first] aircraft in Wichita, we already have stripped out a lot of the cockpit equipment, as well as cabin equipment to do the wiring and communication element modifications. Also, there are support equipment modifications in the lower lobe, below the flight deck."
White adds that "part of the upgrade is to deal with ‘Mode S,’ which is the new European air traffic management capability. So, as we work with NATO on European and global air traffic management [GATM] requirements, which may include some cockpit upgrades at that time," White says. "We are supporting [the agency] with data gathering alternatives, and the operator community is providing them with input and data."
AWACS’ Radar
On March 17, 1999, the E-3 AWACS Radar System Improvement Program (RSIP), developed and produced by Nothrop Grumman, passed its NATO initial operational capability (IOC) milestone. The aircraft with new radar then promptly went to support the agency’s operations in Kosovo.
Under a program separate from NATO’s mid-term modernization program, all 17 NATO E-3s were to have had RSIP installed by late January. RSIP production was part of a cooperative program involving the NATO, UK and U.S. air forces. Northrop Grumman received a contract for the radar’s production from the U.S. Air Force Materiel Command’s Electronic Systems Center.
RSIP units have been sent the UK and USAF for retrofit. The UK is expected to have all of its seven E-3s updated with RSIP by February 2001, according to Teri Marconi, Northrop Grumman’s manager of business development for airborne surveillance systems. The USAF has ordered 15 radar units so far but is expected to eventually outfit all 33 of its E-3s. The Royal Saudi Air Force, France and Japan—all AWACS operators—are candidates to acquire the new radar, as well.
According to officials with Northrop Grumman’s Sensors and Systems Sector, in Baltimore, Md., "A major objective of RSIP is to increase the radar sensitivity against smaller radar cross section targets—say, F-16 or Cruise missile-size—through replacement of the digital Doppler processor and radar data correlator with a state-of-the-art surveillance radar computer, and the translation of the associated software into Ada language.
Additionally, the man-machine interface is improved by modification of the radar control and maintenance panel, which will incorporate a spectrum analyzer, special test equipment, and new displays.
Full-scale production of RSIP was given the green light in 1997.
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