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Data Selectivity Vital To Operational Picture

May 2001
By Christian B. Sheehy

Open-ended networking platform provides greater flexibility with a smaller footprint.

Tactical network software may enable deployed U.S. Marines to share data about numerous targets without the bandwidth constraints or large space requirements of other systems. As the principles of network-centric warfare continue to drive the development of military command and control doctrine, this central component network could provide answers to the challenges of system extensibility and interoperability.

A product of Solipsys Corporation, Laurel, Maryland, the tactical component network (TCN) is the latest system to offer the potential to improve the U.S. Navy’s long-standing cooperative engagement capability (CEC). The software is built around collaborative sensory networking, which differs from the CEC concept that is hardware-specific in providing radar data to surface ships across multiple end-user nodes. The TCN architecture is less hardware-dependent, channeling the capabilities of multiple external communications platforms through a single node.

Warren I. Citrin, president of Solipsys and developer of the TCN technology, says the fundamental difference between CEC and TCN is the latter’s capacity to selectively route data to network end nodes. “Rather than sending all network data to each end point, the TCN routes information as needed, without disturbing the overall tactical picture,” Citrin indicates. “The real benefit of selective routing is that available bandwidth is rationed efficiently, ensuring that all the data transmitted can traverse the network.”

The CEC primary objective is to enable units of a surface task force to achieve a single integrated picture of potential aerial threats. The system comprises line-of-sight data distribution system radio and cooperative engagement processor technology mounted on each end-user platform. Units launching an anti-air or antiship missile can use track data relayed from another unit to guide a weapon system to the target. Each participating unit on the CEC network receives information about launch activity. As the number of units increases, network bandwidth requirements rise, potentially leading to data compression that can result in abbreviated end-user reception.

The TCN solution could eliminate these bandwidth constraints. “Instead of relaying all of the information on a target between network nodes, the TCN architecture fuses the data from multiple sensors using track-specific algorithms,” Citrin explains. “The result of this fusion process is that only data essential to the overall tactical picture is received by all end users. Data that is user-specific is transmitted only to the individual units that require it. This frees bandwidth that would have otherwise been filled by information extraneous to the big picture.”

At the core of TCN technology are a number of generic software applications that enable independent component support of individual sensor systems. The resulting framework is a foundation based on collaboration- and portability-enabling design aspects that can accommodate multilevel data exchange across different distribution networks. Unlike the single CEC network architecture, the TCN scheme combines a variety of networks to create a common frame track picture that coordinates data users. Information is transmitted according to the level of track accuracy needed at user end points. Data accuracy levels are determined by track identity, type, category and geographic location. This determination is based on the state of a particular track, be it situational awareness, tactical or engagement.

The TCN process involves several stages. At the element-server level, data are correlated, associated and tracked once received from local sensors. What are referred to as associated measurements of each track are returned to the appropriate sensors for dimensional verification. These associated measurements are processed by data conditioners that produce current observation related estimates (COREs) from the track information received. Based on the track state of a network, the COREs are synthesized to create fusion algorithm combined track (FACT) states that data conditioners use to determine element-server-request accuracy levels.

“The key process is the data transition from CORE to FACT,” Citrin notes. “Once the data conditioners have prioritized the data according to track state, individual element server requests can be answered, ensuring that the most important information gets to the right user at the right time.” As the TCN processes data, a common-frame-track picture is developed that is shared by each element server. Data pertinent to specific servers is incorporated within the common-frame-track picture only if it is relevant to the big picture. If not relevant, it is received by the appropriate element servers according to track-state accuracy.

Messaging between element servers occurs as local COREs are distributed through data conditioners prior to FACT transition. The addition of single-node servers to a network does not affect the computational complexity of existing tracks because the data conditioners will immediately assimilate new servers based on reporting need. Likewise, network bandwidth requirements remain virtually unchanged because the distribution of available space is a factor of track-state accuracy, not element-server population.

TCN data visualization occurs with the completion of FACT processing. Using standard browser-based hypertext transfer protocol, laptop computers display streaming TCN data within a tactical display framework. “Without the large footprint of a data distribution system radio or a cooperative engagement processor, the tactical display framework can be tailored to fit the mission requirements of most military deployments,” Citrin remarks. “Operating in conjunction with satellite and Global Information Grid networks, TCN technology can be used for anything from Internet-based applications to joint tactical video communications.”

Maj. Rey Masinsin, USMC, company commander of the Tactical Air Command Center, San Diego, contends that Marine Corps interest in TCN technology stems largely from a demand to consolidate information at the field level so that warfighters have only the information they need to complete a mission. The real challenge is doing this without sacrificing data fidelity or integrity. “Unlike CEC, where network users pass all of their measurement data to the cooperative engagement processor to get a single output, TCN allows the selective movement of information so that personnel don’t have to sift through massive amounts of inapplicable data,” Masinsin indicates. “By allowing existing, field-ready sensors to conduct data transfer and contribute to the big picture only when the information received adds to the quality of the transmission, the efficiency and effectiveness of a mission increases dramatically.”

Another area of interest to Marine Corps command and control research is the degree of system invasion required for modifications during time-sensitive multisensor operations. With CEC architecture, adaptations must be made to the system software before new sensor or combat systems can be integrated into the network. “Issues of time consumption and cost become large factors quickly if you need to alter your software each time you add a new capability,” Masinsin explains. “To this point, we have found no apparent software modifications necessary using TCN technology. The data is simply conditioned according to system needs and then transported.” In addition to the time required to make software alterations, operational changes to radar and combat systems also require time for equipment testing to see how the modified system will behave, he adds.

The incorporation of sensor technology into CEC network architecture, including systems such as the Navy PPS59-V3 surface-to-air radar and the Marine Corps ANPPS-73 air control radar, has been an ongoing effort of the Tactical Air Command Center. “If we can employ a software package that can operate two different sensing systems without major software modifications, it certainly makes life easier in a real warfighting scenario,” Masinsin notes. “Recent tests with the complementary low-flying weapons system have shown the advanced medium range air-to-air missile system potentially useful as a ground-vehicle-[mounted] launch weapon. These and other systems could be made much more effective with the coordination capacities of a TCN.”

Weight and mobility are also important factors in the decision to integrate systems. “Our preference is for systems that comprise little standard equipment and support ease of movement,” Masinsin admits. “In a battle scenario, moving a CEC data distribution system radio and its accompanying cooperative engagement processor requires a heavy, high mobility multipurpose wheeled vehicle with the capacity to support a large antenna. In many situations, this would not be feasible. The TCN operates using equipment already in the field such as low bandwidth communications like the enhanced position location reporting system or the single channel ground and airborne radio system. The fewer bulky system-standard components to transport, the better.”

In the arena of battlefield picture manipulation, the need for easily scalable visual displays to accommodate added tactical scenarios is also part of Marine Corps research. The TCN tactical display framework is a Java-based application that is architecture-neutral, allowing users to transition from rapid operation laptop use to long-term protected operations. Expandability is also an issue when visual displays need to be upgraded to include additional features. Minimal dissection of display coding to accommodate add-ons is essential to maintaining near-real-time functionality, Masinsin adds.

“CEC hardware dependency is a problem for today’s fast-moving expeditionary force,” Masinsin reports. “The objective is to keep mission-necessary equipment to a minimum without sacrificing strike potency. TCN’s architecture enables greater flexibility in participatory hardware, while still maintaining a high level of technical robustness.”

Efforts to improve the CEC capacity to support a single integrated air picture that meets Navy and Marine Corps requirements are ongoing. “The strength of CEC is in its ability to produce accurate kinematic data on the velocity and position of given targets,” Masinsin indicates. “It lacks in the area of attribute information such as marking and origination data, which helps a unit amplify a target’s identity. With TCN, kinematic data can be superimposed with attribute data to produce a more fluidly integrated picture of a battle’s air space. The high fidelity that CEC possesses in target acquisition and neutralization is not supported by the necessary battlefield management command and control communications capability that TCN technology provides.”

To improve upon CEC capabilities, the TCN architecture is built around a triad of components. Coupling the tactical display framework with multisource correlator tracker technology within the confines of a TCN represents the basic operational scheme of interest to Marine Corps application, Masinsin comments. In a surface-to-air tactical engagement situation, CEC targeting is limited from a user standpoint due to bandwidth constraints that prevent the maintenance of a common attack framework. In many cases, this framework could be stabilized with a more efficient means of data routing. The TCN brings the picture into focus by combining the assets of multiple communications platforms, then maintaining the picture by moving data as and where it is needed, he adds.

Further testing of TCN technology in combination with existing global positioning system low bandwidth communications, such as the joint tactical information distribution system, is scheduled for summer 2001. Comparison tests of CEC and TCN technology continue as part of ongoing joint system evaluations. Military adoption of TCN technology could begin as early as the third quarter of 2001 following bidding results on product integration into the Marine Corps’ common aviation command and control system.