J-STARS — AWACS for the Ground

The performance of stealth, precision weapons, and unmanned vehicles in Desert Storm was complemented by other technologies that lent greater visibility for the allied force. To an extent unprecedented in military annals, the “friction” that Clausewitz described was lessened when a prototype ground surveillance, targeting, and battle management airborne platform unmasked the battlefield and revealed to allied ground commanders a continuous picture of both friendly and enemy forces in near real time across a wide area of the Persian Gulf theatre of operations.

Two airborne systems, known as the E-8 Joint Surveillance Target Attack Radar System (Joint STARS or J-STARS), were deployed to the Persian Gulf immediately prior to the coalition’s air offensive. Every night of the war at least one E-8 was airborne. Under the control of the joint force commander, Joint STARS flew 49 dusk-to-dawn missions in all weather conditions, effectively denying the enemy the usual benefits of tactical ground force movement under the shield of darkness and adverse weather.

General Merrill A. McPeak, then chief of staff of the US Air Force, compared the capabilities of Joint STARS with those of an E-3 Airborne Warning And Control System (AWACS): “Joint STARS can do for ground attack aircraft what AWACS does for interceptors; that is, creating a very tight loop between surveillance and operations . . . allowing air commanders to attack mobile units while they are in the manoeuvre phase and long before they can reach our ground forces.”

Airborne Surveillance / Command And Control Platforms

Platforms such as the US Air Force’s E-3 Sentry and the US Navy’s E-2C Hawkeye have served for decades as bulwarks of American airborne surveillance and battle management capability. These aircraft provide a comprehensive picture of events as they occur and communicate activities to a multitude of allied aircraft. Since the early 1980s, NATO-owned E-3s have been the “eyes” for NATO’s command and control and maritime surveillance requirements while E-2Cs have been performing the same mission for the US Navy plus Egypt, Japan, Israel, Taiwan and Singapore.

The US Air Force/US Army Joint STARS program adds ground-based operations to the traditional missions of airborne surveillance and battle management systems. Joint STARS evolved from a requirement to track and assist in halting a massive Warsaw Pact ground offensive in Europe. Its performance under very different operational circumstances in Desert Storm demonstrates the enduring relevance of Joint STARS in the post Cold War period – both for providing military commanders with precise tracking and targeting of ground and slow moving airborne targets, as well as in operations other than war. Joint STARS is being developed as the critical monitoring system for effective battlefield management as well as maintaining peace in tense regions across the globe and deterring conflict between potential enemy forces.

Advancements in radar and computer technology have given Joint STARS a significant advantage in information processing over other airborne battle management systems. Joint STARS offers two complementary elements: an airborne system and ground station modules. Within the airborne platform, radar information and command messages are exchanged via a local area network to encrypted, jam-resistant digital datalinks for interoperability with an unlimited number of mobile Army ground station modules, tactical aircraft, and other airborne surveillance systems. Air Force command centres receive the information through the Joint Tactical Information Distribution System (JTIDS) for tactical air navigation operations.

Joint STARS also includes voice communications through several encrypted VHF radios and HF sets. The flight crew comprises a pilot, copilot, flight engineer, navigator/self defence suite operator, and up to 17 Air Force and Army operators who have access to radar data displayed as real time “moving imagery” on large screen graphics consoles.

The Joint STARS airborne system represents a complete operations and control centre aboard a modified Boeing 707-300 series aircraft. The aircraft’s design includes a distinctive radome, located under the forward fuselage, housing a 7.3m (24ft), multimode, phased array radar antenna.

The radar system operates in several modes. In its wide area search, Moving Target Indicator (MTI) mode, the radar can detect, identify, and track more than a thousand moving targets – jeeps and armoured vehicles, patrol boats, tactical missile launchers and slow flying fixed and rotary winged aircraft. The search area covers nearly 50,000 sq km and can be conducted at standoff ranges exceeding 200km. A sector search mode allows the operator to break down hostile convoys into individual vehicles to plot a precise target for airborne attack. Operators can even discriminate between wheel driven and track driven vehicles. If a target stops moving, the Synthetic Aperture Radar (SAR) mode can provide a high resolution, nearly photographic image of the stationary vehicle, its precise location and surrounding terrain.

Radar images can be overlaid with prestored cartography including roads, rivers and geographical borders. A historical replay feature allows airborne operators and ground commanders to record and replay ground force movements at user selected speeds for closer analysis – much the same way a football team might analyse an opponent’s last few games through the use of video tapes. Just as video helps the football coach, so the moving imagery of Joint STARS enhances intelligence for the theatre commander. The replay feature gives ground commanders overall trends that may not be obvious in real time observation or in still images.

Joint Stars History

Grumman was awarded a full scale development J-STARS contract, covering the conversion of two Boeing 707 airliners to serve as prototypes, in September 1985. The first of these prototypes first flew in converted E-8A J-STARS configuration on December 22, 1988.

Originally the USAF planned to acquire 22 new build E-8B production J-STARS, powered by F108 turbofans (CFM56s), and one airframe was built (and flown in 1990) before the US instead opted to convert secondhand Boeing 707 airliners into E-8Cs. The two E-8A prototypes will be upgraded to E-8C standard to serve alongside 18 production E-8C conversions. The first E-8C production aircraft first flew in March 1994, although it will be used as a permanent testbed. The E-8Cs will be operated by the USAF on behalf of the US Army, with first deliveries due in 1996.

The heart of the E-8 is the Norden APY-3 side looking phased array multimode radar, which is housed in a canoe fairing beneath the forward fuselage. In synthetic aperture radar mode the APY-3 can image targets up to 175km distant and can survey one million square kilometres in one eight hour sortie. Pulse doppler modes gather moving target information allowing the operators to track moving vehicles and convoys.

Joint STARS provides ground commanders with a complete overview of the battlefield and can also be used for specific target reconnaissance and for individual targeting functions. E-8 gathered information is relayed to mobile ground stations (with operator stations similar to those onboard the aircraft) via datalink, allowing individual ground commanders to access specific information they require.

The two E-8As were hastily deployed to the Gulf War in 1991 where they flew 49 operational missions, providing invaluable information to ground commanders and proving the concept in a real war environment. More recently, J-STARS has been successfully used over Bosnia.

Conflict Prevention

Information shortfall on the movement and location of ground forces can create an immense obstacle for those attempting to prevent conflict.

Until the development of Joint STARS, ground surveillance systems were handicapped by various limitations. Moving vehicles could not be reliably detected, let alone accurately located and tracked in real time. Adverse weather and darkness caused severe degradation in surveillance capabilities. Only a small area could be observed with great resolution, usually from short ranges, causing large areas to be unobserved much of the time because of insufficient surveillance assets. Processing data from these systems into usable information and providing this intelligence to appropriate decision makers took too much time. Observation by airborne and space systems, which have the best perspective, was often limited to a relatively brief period of time – rarely much longer than an hour.

Joint STARS’ unique combination of surveillance capabilities removes many of the limitations that handicap other ground surveillance systems. In addition, the common communication links aboard Joint STARS allow the system to operate in conjunction with other surveillance systems, such as AWACS and unmanned vehicles. This synergy further enhances situational awareness. The ability of the Joint STARS platform to be airborne for 11 hours – which can be extended to more than 20 hours by inflight refuelling – helps ensure surveillance coverage that meets mission requirements.

Situational awareness continues to be critical to successful conflict prevention. It maximises the diplomatic and military options considered most appropriate for defusing a developing crisis. Once an option is selected, monitoring capabilities offer important information that may reveal a need to modify actions.

The level of awareness that ensures early recognition of a developing threat often requires near real time detection and simultaneous monitoring of many complex and seemingly unrelated actions or indicators. When this type of surveillance is in place, dangers posed by theatre wide patterns of related actions are easier to recognise.

Joint STARS’ ability to see movement on routes and in garrisons could have value for other crises including terrorist acts. For example, cued by an agent’s warning or by replaying the tracks of a vehicle known to be involved in a terrorist incident, Joint STARS surveillance – coupled with intelligence from other sources – could provide information on terrorists’ movements, contacts, safe house, supply locations, and whether neighbouring countries are involved. The recorded Joint STARS imagery could provide irrefutable evidence of such involvement.

Peacekeeping And Peace Enforcement

The success of Joint STARS in providing Desert Storm commanders with superior situational awareness of the land battle underlines the system’s value for preserving peace. The deterrent effect of Joint STARS could prove to be very cost effective while minimising risks to allied forces. The use of this system may inhibit an aggressor planning an invasion. Joint STARS could virtually negate an invader’s element of surprise. And the dissemination of Joint STARS’ imagery to the world community would represent irrefutable evidence of a developing threat, possibly prompting responsive deployments that could further reduce the probability of war.

The roles of Joint STARS in war and operations other than war will make it a valuable asset of US security policy. The enhanced ability to tailor the US military response to a developing threat will become increasingly important as the size of the US military and its transportation resources continue to decrease, and as more forces are located in the continental United States. While the risks of a limited deployment response during the initial period of war are obvious, overresponding also can pose significant pitfalls. The US may need those same forces to confront a second regional contingency. An excessive deployment in response to every threat may entail unnecessary expenditures, an increasing concern in an era of declining defence spending. Joint STARS allows a more accurate fit between threat and response.

The most significant breakthroughs in defence technology during the Cold War have been primarily in the area of weaponry – nuclear missiles, stealthy jet aircraft, precision guided weapons. The extent to which other capabilities such as airborne surveillance and battle management can provide profound breakthroughs will depend on strategic decisions and training doctrines implemented over the next several years. The measurement of “ground power” has certainly evolved from the Cold War era Soviet tactics of amassing tanks and infantry fighting vehicles. In fact, some Soviet military leaders argued in the early 1980s that a new “military technical revolution” was occurring in military affairs, based on the integration of reconnaissance and strike systems. Post Soviet Russia’s official military doctrine endorsed in 1994, focuses research and development efforts in the areas of deep strike and information weapons, including reconnaissance, surveillance, and target acquisition systems as well as “intelligent” command and control systems.

As the technological development of the digital battlefield continues at a furious pace, future warfare may depend as much on how commanders effectively “unmask the stage” of conflict as on the weapons they direct during the course of the battle. Courtesy The Northrop Grumman Review magazine.