Victory at CEC

by Brendan P. Rivers and Michael Puttre
Sep. 1, 2001

On the morning of May 17, 1987, the USS Stark (FFG-31) was on patrol in the Persian Gulf as part of an operation to protect neutral shipping during the Iran-Iraq War. A few minutes after 9 am, an Iraqi Air Force pilot flying a Mirage F-1 fired two Exocet missiles at what he believed to be an Iranian tanker about ten miles ahead of him, scoring two hits. The "tanker" turned out to be the Stark, and the explosion and resulting fire claimed 37 lives and injured 21 others.

The destruction of the Stark brought home to Navy planners something that many were already talking about: that the fleet – and individual ships in particular – needed better protection from airborne threats. This eventually led to the establishment of a program to develop a Cooperative Engagement Capability (CEC). CEC is a system of hardware and software that allows the sharing of radar-track data on air targets among the ships in a battlegroup. Track data from individual ships is transmitted to other ships in the group via a line-of-sight (LOS), C-band data-distribution system. Each ship uses identical data-processing algorithms resident in its cooperative- engagement processor, resulting in each ship having essentially the same display of track information on aircraft and missiles, or single integrated air picture.

The result is a revolutionary new way of engaging airborne threats - employing multisensor measurement fusion as opposed to single sensor tracks to allow battleforce-centric, rather than platform-centric, engagement. An individual ship can launch an anti-air missile at a threat aircraft or anti-ship cruise missile within its engagement envelope based on track data relayed to it by another ship. Moreover, all of the weapons in the battlegroup, regardless of platform, are available to any authorized commander – in theory, anyway. With extensions in place to land-based air-defense systems and coalition forces, the availability of weapons extends to the entire theater.

Initial work on CEC development was carried out by the Applied Physics Laboratory at The Johns Hopkins University (Baltimore, MD), then handed off to an industry team led by Raytheon Command, Control, Communications, and Information Systems (St. Petersburg, FL). Right away, it was understood that "it was going to be necessary to do something different," said Tony Gecan, systems engineer for Raytheon.

Seeing With CEC

Modern threats are difficult to detect, let alone track. Add to this the effects of enemy jamming, atmospheric conditions, and that fact that radars sometimes just go into fade (it happens) and the magnitude of the problem becomes clear. Furthermore, radar is, by its nature, most precise in measuring range. Measuring target bearing and elevation can be more problematic. The solution to all of these problems is to "box" the target with multiple radars. By exploiting geometric and frequency diversity among the ships - and in some cases, aircraft such as the E-2C Hawkeye - in a battlegroup, CEC fills the holes that appear in a single ship's radar track of an airborne object, resulting in a radar-track picture that is an order of magnitude more accurate than one generated without using the technology. The CEC concept is founded on the notion that, as Gecan put it: "Somebody always sees the target somewhere. You get two sensors with the right geometry and you can nail the target right quick. And that's only with two sensors. It is not difficult to imagine the speed with which a target could be accurately located using all of the available sensors within a battlegroup."

The composite tracking function of CEC enables each member of the network to share individual tracking data, assembling a single integrated air picture of fire-control-quality data that is common throughout the battlegroup. This mitigates the effects of enemy jamming, bad weather, or random fades. The challenge is to ensure that there is only one track per object. The result is what is called a composite track, and it is conceptually straightforward. A Ticonderoga-class cruiser in the battlegroup is tracking a cruise missile, but loses it for a time due to the effect of enemy jamming. An Arleigh Burke-class destroyer in a different location tracking the same cruise missile is likewise dealing with the effects of enemy countermeasures and, at the same time, is contending with bad weather. The Nimitz-class aircraft carrier that is the ultimate target of the cruise-missile attack does not have the Aegis Combat System, and there are gaps in its track. CEC may eventually be capable of networking over 100 platforms to create these composite tracks.

The challenge here is to assign each detected object a single track. The more platforms you have looking at things, the more confusion will result about who is seeing what. This is a problem with existing datalink networks. According to Raytheon's analysis, a recent All Services Combat Identification Evaluation Team test demonstrated that a network of CEC-equipped platforms created 1.06 tracks per object, which is a considerable improvement over the 1.35 tracks per object generated by a Link 16 datalink network and a vast improvement over the 1.5 tracks per object generated through normal communications. Nevertheless, a battlegroup consisting solely of CEC-equipped platforms is unlikely, and some fusion of heterogeneous track data is to be expected. Raytheon says its data-fusion engine reduces the number of tracks per object in a mixed CEC/non-CEC network to 1.2, and that it will be able to reduce this further toward the Platonic ideal of one track per object.

Another challenge is to prevent every platform in the battlegroup with a missile from popping off at every enemy in range - a great way to run out of irreplaceable stores before the second wave hits. The oft-stated goal of network- centric warfare, particularly with regard to air defense, is to apply the right weapon for the right target at the right time. Also, CEC enables a platform to launch a long-range missile at a threat that would be beyond the range of its organic sensors, taking advantage of the full kinematics of modern missiles. Command and control, therefore, is an import component of CEC. The single common integrated air picture that is a product of the individual node processors and that is shared with all members of the battlegroup is the basis of this command and control capability. It's as if all of the commanders of the battlegroup could be standing around the same situation map: "You shoot at that one, you at that one, and I'll take out this one over here."

In order to share track data, CEC needs a means of communicating among the participants in the network. This is accomplished via the wideband data-distribution system, the backbone of the CEC system. The data distribution system consists of a powerful transmitter and a phased-array antenna onboard each CEC participant - or node - in the network. The measurements from each of these nodes are then coalesced to arrive at the single integrated air picture. Care has been taken to avoid the obvious danger to the network posed by enemy jamming by using "every trick in the book," Gecan said, such as frequency hopping, interleaving, etc. Furthermore, the transmitters are powerful enough that the system should be able to muscle through any enemy attempts at jamming: "Our signal will be the last man standing on the electronic battlefield," Gecan said.

The most important operating principle is pair-wise access of nodes. There is a schedule of pair-wise access connections by which every member (node) of the battlegroup talks to every node in its line of sight (and beyond, when SATCOM capability is introduced) in order to share tracking data and node-position data among them. The data are combined, updated, and time-stamped to form the single integrated air picture that is only as old as the last complete cycle of pair-wise connections. Each connection is directional, made by steering beams with the phased array antennas, and scheduled in advance. The scheduling routine is dynamic, so if a node becomes a casualty, has a fault, moves out of range, or is otherwise unavailable to a node with which it was scheduled to communicate, the interrupted pair-wise connection is cancelled, and new schedule of pair-wise connections is issued to all surviving nodes. Similarly, if a new CEC-compatible platform introduces itself to the network, a new schedule is generated that incorporates it. This way, CEC does not have a single point of failure and can accept reinforcements on the fly.

To invoke a computer analogy, CEC is like a peer-to-peer network where its components are plug-and-play. There is no central server that kills the network if it goes down. Individual compatible nodes can come and go from the network as casualties, reinforcements, reassignments, etc., without interrupting service. Of course, this speaks only for the single integrated air picture. The effectiveness of the battlegroup in the face of an evolving battle will remain the responsibility of officers in the chain of command.

As with any computer network, the key to CEC is commonality. Consistency within the network is critical. The system uses common data, algorithms, and processing to create the all- important single integrated air picture for each eligible participant in the battlespace. Every CEC-compatible sensor has a software "adaptive layer" that enables it to pass information to a dedicated on-board processor. This processor, in turn, interfaces with the combat system of the host platform. Raytheon has developed adaptive layers for most phased-array and rotator-type radars in service with the US Navy, as well as air-defense type radars in use by the US Army and Marine Corps. Raytheon says it is in the early stages of developing an adaptive layer for the Theater High-Altitude Air Defense (THAAD) X-band phased-array radar. Studies are also under way to determine the usefulness of integrating AWACS into CEC.

Swinging For the Fence

As noted, CEC already has a long history. First demonstration of CEC technology took place in 1989, only two years after the Stark incident. Developmental testing took place in 1993-94, and initial operational capability of the shipboard version, designated AN/USG-2, came in 1996 on USS Hue City (CG-66) and USS Vicksburg (CG-69), both of which experienced significant teething problems involving unreliable tracking data. The US Navy League reported that during an initial operational test and evaluation of the AN/USG-2 equipment set conducted on the amphibious assault ship USS Wasp (LHD-1) in July 1997, operators aboard encountered considerable interoperability difficulties when operating Advanced Combat Direction System (ACDS) Block 1 CEC and the tactical digital datalinks concurrently: "On the ACDS Block 1 consoles, the operators were overwhelmed with inconsistent data, alerts, and identification conflicts. Subsequent testing of CEC with the Aegis Weapon System Baseline 6 Phase 1 aboard the guided-missile cruisers USS Hue City and USS Vicksburg in early 1998 showed similar interoperability and combat system problems." An airborne version of CEC, designated AN/USG-3, has seen air- development testing (1995) and flight tests aboard an E-2C Hawkeye (1998).

Over time, integration issues were tackled one by one, and a series of at sea tests in September and December 2000 designated Underway 10 and Underway 11, respectively, demonstrated CEC operability with a realistic battlegroup involving CEC - and non-CEC-equipped - destroyers, cruisers, carriers, amphibious-warfare vessels, as well as aircraft. In May 2001, CEC underwent operational evaluation (OPEVAL). The results of the OPEVAL were released to the Navy in late August, and at press time, the industry partners were awaiting the release of those results. According to one industry source, though, all indications are that CEC will be given the green light for full-rate production. Currently, 21 CEC systems are in use with the US Navy under low-rate, initial-production contracts. These systems are deployed on varying platforms including ships (Ticonderoga class, Arleigh Burke class, Nimitz class, and Wasp class) and aircraft (Hawkeye) as well as land-based units (Patriot and HUMRAAM) for test purposes. Raytheon said it expects the Navy to equip approximately 200 platforms with CEC.

But CEC development is far from over. In the future, CEC will use GPS rather than relative-position data for more precise measurements. The data rate will be increased to two and a half times the current norm. Selective use of smaller frames will reduce latency. Multibeam antennas will be employed to permit point-to-multipoint communications. Even lower-bandwidth users will be able to receive selected CEC data. Data will also be tailored to customer media, such as the Tactical Common Data Link. In addition, CEC will also make the move from LOS to satellite communications, a shift that will take some effort to accomplish. Alongside these enhancements, Raytheon is also currently working with the Office of Naval Research to integrate precision ESM into CEC. The idea of using the powerful CEC transmitters for jamming is also being explored.

But perhaps one of the most interesting developments underway is the use of CEC for theater ballistic-missile defense (TBMD). The US Ballistic Missile Defense Organization is funding research into a Joint Composite Tracking Network (JCTN) - a real-time network, based on the CEC program, that directly links sensors and shooters within a theater. Lockheed Martin Naval Electronics and Sensor Systems (Moorestown, NJ), overall CEC systems integrator and producer of the Aegis weapons system, is currently under contract to develop CEC Version 2.2 (v.2.0 was for Aegis integration, and v.2.1 incorporated features for non-Aegis ships), the next stage in CEC growth, which will allow the system to deal with the ballistic-missile threat. Lockheed Martin's program plan calls for integration of CEC v.2.2 into Aegis in December 2004.

Version 2.2 of CEC basically adds the capability to assess the theater ballistic missiles, creates a TBMD track picture, and also provides engagement coordination across the battleforce. "When you're dealing with TBMD, it's somewhat different from anti-air warfare," said Mark Trenner, director, Naval Command & Control Programs at Lockheed Martin - Moorestown. "The speeds and the dynamics that you're looking at change demonstrably. You're talking about something that moves much, much faster and is much, much higher up in terms of altitude. The differences in distance affect look angles, and geographic diversity becomes more important. How much radar illumination, from what aspects, can you put on this potential target? How can that aid in target discrimination and missile fly-out trajectories? And then how do you get that information around the battleforce so that these distributed components can coordinate to ensure that you're taking best advantage of your radar and your weaponry resources?"

Then there are the problems inherent in integrating anything as complicated as the Aegis Combat System. Trenner points out that Aegis has about three million lines of software, an extensive hardware suite distributed over the whole ship, and is topped off with a very sophisticated radar. Into this comes CEC, which is the first iteration of extending a network of similar complexity throughout a battleforce. "We're talking about moving high-fidelity information across vast distances with very harsh timelines to meet radio-transmission budgets," he said. "Also there are latency requirements such that the combat systems that are being supported with that data can actually use it with some degree of confidence and know that the ellipse errors in terms of tracking are within the parameters of acceptability and the latency of the information."

Paul Lemmo, director of business development, said Lockheed Martin has two full Aegis weapon systems worth of equipment online at its Moorestown Naval Systems Computing Center to assist in the Aegis CEC-TBMD integration effort. This facility has the real computers that represent the computational resources of the Aegis weapon system, all of the operational console positions, and even the cable types are replicated to a very high degree. "We can integrate and check out real scenarios with real data using two Cooperative Engagement systems that we have here, courtesy of the US Navy," Lemmo said. "So we can essentially do a battlegroup test and significantly reduce the risk before the Navy does testing at sea."

Everybody on Board

CEC is currently structured as a closed network. This means that only CEC-capable platforms participate in pair-wise connections and, thus, contribute to building composite tracks and the single integrated air picture. Tracking and air-picture data can be exported to non-CEC platforms over Link 11 and Link 16 (and eventually SATCOM); however, these are consumers only. Ideally, coalition partners of the US would want to participate as equals in the battlegroup.

Lockheed Martin and Raytheon System Limited (RSL), the UK-based subsidiary of Raytheon, were awarded one-year integration studies in 2000 by the Ministry of Defence to take part in the UK's CEC Program. These studies will explore the integration of CEC into the Royal Navy of its Type 23 frigates and future Type 45 destroyers. In addition, the Royal Australian Navy and the Japanese Navy have expressed intent to implement CEC in their own platforms. The Republic of China (Taiwan) has been mentioned as another potential candidate for CEC technology, although such a development would certainly alarm the People's Republic of China.

Ultimately, the goal of CEC is to keep fleets as a viable instrument of warfare in the face of ever-evolving air threats. Historical challenges to individual vessels in the form of submarines and aircraft have been countered with cooperative naval action: convoys and task forces, respectively. The new generations of cruise missiles slice away at the time a fleet has to respond to their threat. CEC is an effort to remove the weakness of individual platforms by making each an extension of the battlegroup, with every other ship, aircraft, and land-based system standing behind it, ready and available to engage.