Commercial internet technologies are coming to the aid of military commanders
Graham Warwick/Washington DC
Information is everything - in commerce and in warfare - and the technology that enabled the internet explosion is now empowering military commanders.
"There is a real argument that the business-to-business and business-to-consumer infrastructure behind e-commerce is really in the same class as the core infrastructure used to plan and execute a battle," says Doug Barton, chief architect, aerospace information operations, for Lockheed Martin Mission Systems.
"Whether it is a military order to go attack something, or a civil order to buy 500 pairs of socks, it is really the same thing," Barton says. "In both cases, the information needs to be reliable and timely or the order will fail and the customer will go elsewhere - or get killed."
In command and control, as in e-commerce, the infrastructure needs to be available "24/7", able to handle a high transaction rate and communicate with a distributed community, convenient to access from any device and capable of being configured to meet the data needs of different levels of user.
Lockheed Martin is responsible for development of the USAir Force's new Theatre Battle Management Core System (TBMCS) - the software suite now being used in operations centres to plan and execute air battles. TBMCS is being transitioned from a client-server to a web-based architecture.
"The next delivery will have very substantial web components," says Barton. "The core technology comes from commercial vendors which have formed strategic partnerships with Lockheed Martin." Commercial suppliers have been actively involved in development. "They bring products...and a design pattern used successfully in the commercial market."
Legacy systems
The military's migration to the web is gathering pace. The US Department of Defense's Global Transportation Network, a supply-chain management system developed by Lockheed Martin that allows 6,000 users to track shipments, is now all web-based. "It was a client-server, with a 1,000-box client. Now it goes out over the web to any browser," Barton says.
Under the 15-year, $1.5 billion Integrated Space Command and Control programme, the company is modernising the USAF's Cheyenne Mountain aerospace command centre, a task which includes integrating 30-40 legacy systems into a new web-based infrastructure.
"We don't use a commercial architecture 'out of the box'. We tailor it," says Barton. With extensions, commercial systems from the likes of Oracle and Sybase "can meet the bulk of our database-management requirements". Other examples include message-translation "middleware" that can be used to integrate existing systems and databases.
The DoD is keenly watching developments in the e-commerce area, particularly the move to XML as the new standard for electronic data interchange. Barton says XML will be the next generation DoD and NATO-standard message format, replacing today's "huge and rigid" defence messaging infrastructure.
Today, air tasking orders are sent out by operations centres as fixed-format messages comprising immense strings of characters. To understand the orders, "you have to know that the first 12 characters are the mission number, the next six are the date, and so on", says Barton. In XML, the data "self-describes", opening up the possibility of machine interpretation of messages.
Machine knowledge
"The next frontier is to enable the system to better understand the data," Barton says. "Today, a human can look at the data and recognise the meaning of the message. A machine cannot." Exchanging track data in XML could, for example, ease the burden of synthesising and distributing a picture of an air battle.
Information technology is finally enabling the theatre commander's dream that all his forces share the same real-time view of the battlefield. The US DoDis working towards a capability it calls the single integrated air picture (SIAP) - essentially a real-time database shared between users, ranging from the joint chiefs to forces in the field.
The SIAP will be synthesised from data received over both real-time and non-real-time links. Examples of non-real-time links include the Link 16 tactical datalink and a host of other communications networks now used by the DoD. Real-time data is a different matter.
The US Navy is leading the charge with development of co-operative engage capability (CEC), a dedicated real-time network linking the shipborne and airborne radars in a battlegroup to create a single, shared air picture which is accurate enough to allow a warship to engage a target out of range of its own sensors.
The CEC is currently undergoing operational evaluation (Opeval), having completed technical evaluation (Techeval) in March. Early problems with managing the sensor network appear to have been overcome, and both the US Navy and Raytheon anticipate approval for full-rate production.
Raytheon is already under contract for low-rate initial production of 48 CEC terminals, mainly for warships but including units for US Navy Northrop Grumman E-2C Hawkeye airborne early warning aircraft and US Army Raytheon Patriot surface-to-air missile batteries. The UK Royal Navy is the first international customer, and it plans to integrate CEC on its Type 23 and new Type 45 warships.
CEC-equipped platforms share sensor data via a wideband datalink. Rather than sharing tracks, the system exchanges actual radar measurements of target range, azimuth and elevation. The common engagement processor on each platform then fuses the data at the measurement level to produce composite tracks accurate enough to engage a target out of range of the platform's own sensors.
Kill chain
The CEC is basically a radio-frequency local-area network, says Mike Chester, US Air Force CEC programme manager. "It's very high rate, very jam resistant, very directional and very real time." Sharing data in near real-time between sensors gives commanders more time to track a target, confirm its identity and decide how to respond. "CEC is as close to real-time as possible. Latencies are small," he says, adding: "The longer the latency, the shorter the decision time, and vice versa."
With CEC as the starting point, Raytheon is proposing development of the Joint Sensor Network (JSN), a wideband real-time network providing composite tracking from theatre-wide sensors to support synthesis of the SIAP.
The company has mapped out a path for evolution of the CEC into the JSN, which involves expanding the system's capabilities to handle more nodes, exploit more sensors and datalinks, and track more target types.
The first step in expanding capabilities, says Raytheon engineering fellow Dr Tony Gecan, is to move to an absolute gridlock co-ordinate system. The CEC uses relative gridlock, where each platform measures target range, azimuth and elevation in relation to its own position. JSN nodes will report target position with respect to an absolute co-ordinate frame anchored by the global positioning system. "Unambiguous positioning will allow us to export tracks outside the network," says Gecan.
The JSN's tracking capabilities would be expanded beyond the air-breathers - aircraft, cruise missiles and unmanned air vehicles - that are the CEC's focus, to include tactical ballistic missiles (TBMs) and their debris, friendly TBM interceptors and their kill vehicles. "This increases the total number of tracks significantly," says Gecan.
Tracking TBMs
New filtering techniques will allow the JSN to track TBMs during their boost, ballistic and re-entry phases. Adding angle-only filters will allow the system to track targets for which only bearing is known, providing access to "a lot of identification-rich information", he says.
A major increase in capability will come with expansion of the network to encompass more sensors. The CEC is designed primarily to link radars on US Navy Aegis warships and E-2C Hawkeyes. The JSN will expand the network to include additional radar and non-radar sensors, including the Multi-Function Radar for future USN aircraft carriers and destroyers, and the radar for the US Army's Theatre High-Altitude Area Defence system, both under development by Raytheon. "It is our intent that future Raytheon radars will be network-ready," says Gecan.
The CEC architecture includes an adaptive layer which translates sensor data for the co-operative engagement processor. "The benefit of CEC is it does not care what the sensor is," says Chester. This allows the network to be extended to non-radar sensors such as precision electronic support measures and infrared search and track systems. "These provide good identification-related information."
For JSN, Raytheon plans to develop the adaptive layer into a smart interface allowing co-ordinated control of all the sensors on the network. "Today the adaptive layer is largely a one-way street. In future, it will couple the network and sensor together to allow adaptive control and co-ordination of sensors," he says. The result will be a "hypersensor".
More nodes
One of the biggest challenges will be increasing the extent of the sensor network, from around 10 nodes for the CEC to over 120 for the JSN. During development, Raytheon had to overcome datalink scheduling issues which began to surface as more nodes joined the net. "Problems started at seven to eight nodes," Gecan says. Fixes were developed and the CEC demonstrated "robust" link scheduling in the final round of Techeval, which involved eight warships, an E-2C and a US Navy Lockheed Martin NP-3D testbed.
CEC nodes connect by pointing their antennas at each other and exchanging bursts, or frames, of data. These rendezvous are pre-arranged according to a global schedule which must be recomputed every time the network topography changes. Raytheon is developing a more flexible distributed scheduling algorithm to support network growth to 120-plus nodes. Frames will be broken down into fractional frames to "get the data out faster"; and multibeam antennas will allow each node to communicate with three others simultaneously.
Gecan says modelling of 17 different network topologies has validated that the current CEC bandwidth is adequate beyond 50 nodes, with the planned JSN bandwidth providing margin for growth to 120 nodes. "We can get there. There are no showstoppers," he says.
It helps, says Raytheon, that the CEC's composite tracking process makes efficient use of the available bandwidth. Combining range and bearing measurements from two or more radars provides more accurate and stable target tracking than is possible with a single radar. As more sensors in the network see the target, tracking accuracy improves and the need for each platform to transmit measurements reduces, freeing up bandwidth.
"It is not the case that every node transmits all the data," says Gecan. "When it gets enough information to track accurately, the system picks the best measurements and transmits only those needed to keep a tight track." Bandwidth use actually decreases as the number of nodes on the network increases. "The number of measurement reports per track decreases as more nodes and sensors are added. This allows us to maintain precise tracks with fewer sensors."
Disadvantaged users
A critically important part of Raytheon's evolutionary strategy is to extend the sensor network and disseminate its air picture to low-bandwidth or "disadvantaged" users, such as commanders in the field. "We will extract tracks of interest and fire them off to other nets," says Gecan. This will be achieved by developing gateways between the wideband CEC and narrowband networks such as Link 16.
Expanding the network beyond the line- of-sight limits of the current datalink will require satellite communications. "Theatre-wide operations need beyond line-of-sight links, and satellites are ideal because they are line-of sight to everybody," says Gecan. "They allow us to operate a network throughout the theatre and export tracks to other users."
Satellites have an important role in the network's ability to track theatre ballistic missiles. "It's critical the network synthesises and sends a complete picture of the TBM battle to all interested parties," says Gecan. "Then everybody sees the incoming tracks and gets multiple opportunities to shoot."
Raytheon believes the US Navy's CEC is an ideal basis for the DoD's SIAP because it meets the stringent requirements for data integrity and synchronisation, by providing extremely stable kinematic tracking. A fusion engine would then correlate identification-related data from other networks with the CEC's composite tracks to update the real-time database from which the SIAP is synthesised.
While it sees the CEC as the likely basis of the SIAP, the company admits it will be a challenge to persuade other US services to adopt a navy-developed system. The first step will come later this year, when the USAir Force conducts simulations to quantify the benefit of integrating its Airborne Warning and Control System into the CEC network.
Source: Flight International