Cyberjet Prepares For Smart Soaring

September 2007
By Henry S. Kenyon

The Taranis unmanned combat aerial vehicle (UCAV) is the largest unmanned aircraft developed by the United Kingdom. Designed for a high degree of autonomy, it will demonstrate capabilities for stealthy, long-duration, deep-penetration missions.
British unmanned combat aircraft demonstrator is designed for long-range missions with limited operator control.

In the near future, robot warplanes could autonomously take off, navigate to their targets and identify them—all before contacting human operators for clearance to attack. This operational independence is the promise of a new program underway in the United Kingdom. Building on experience gained from several other recent technology demonstrations, the project emphasizes systems development and integration. The aircraft’s situational awareness will rely on its ability to process and translate flight and sensor data without human interaction.

Named after the Celtic god of thunder, Taranis is the largest unmanned aerial vehicle (UAV) developed by the United Kingdom. When complete, the aircraft will be roughly the size of a Hawk combat jet trainer, explains Christopher Allam, project director for BAE Systems’ Taranis Technology Development Program, Warton, England. Taranis is a technology demonstrator and prototype for a possible future class of British unmanned combat air vehicles (UCAVs).

The development of Taranis was driven by Ministry of Defence (MOD) requirements for “deep capability”—the ability to operate in hostile environments for long periods of time. It was the need for long-duration operation far behind enemy lines that prompted the government to consider UCAV platforms, says Allam.

The program itself was triggered by several UCAV and UAV platforms being developed by BAE Systems. In particular, the MOD was interested in the Raven program. Allam explains that Raven is a rapid-technology demonstration program designed to combine a variety of technologies into a UCAV platform. It was the merging of the industrial capability to quickly develop and test a UCAV platform in Raven and the government’s needs that initiated the Taranis program.

Another UCAV development platform that contributed to Taranis was the Corax program. Allam notes that Raven and Corax are cousins because both aircraft are designed for a high degree of modularity, sharing many of the same systems and structural features. However, Corax was designed to operate at longer ranges than Raven. “Corax effectively extended the range and endurance of an existing design [Raven],” he states.

Taranis has a high degree of autonomy. Allam notes that autonomy was also an important aspect of the Raven, Corax and High Endurance Rapid Technology Insertion (HERTI) programs, which laid much of the foundation for developing Taranis. “We are trying to test out some of the higher levels of autonomy and look to do things in a different way in terms of going about the systems design,” he says.

The autonomy goal for Taranis is to create a robot aircraft that can taxi, take off, plot a course to a target and locate a target without human interaction. Only when it has reached its target will the aircraft notify ground personnel to obtain target verification and approval before autonomously attacking the target and returning to base. It also will be able to react to sudden changes in its flight environment, such as avoiding other aircraft crossing its path. “What we’re doing is designing a system that’s got variable autonomy to change the way that we interact with the system,” Allam shares. “There are certain times in its mission where you can have closer control, but at other times you may not want to. You’re merely supervising the system.”

Taranis’ autonomous software allows the human operator’s role to vary in terms of direct control to suit the mission. Allam maintains that testing and proving variable autonomy are key parts of the program. “Taranis is all about experimenting and proving new technologies, seeing which ones are useful and which ones aren’t and finding how to move forward,” he says.

Much of the system design for the UCAV’s autonomous capabilities is complete. BAE Systems programmers are now coding the aircraft’s software. Allam shares that in the late spring, the firm released the first design for the autonomous control system. The design team is currently testing and coding that design for the “first drop” of the software system.

The HERTI platform shares the same autonomous software architecture as Taranis. Although it is a reconnaissance UAV, HERTI was designed for high autonomy and has many similar operational functions embedded into its software. Where Taranis differs is that its software architecture features autonomous combat and targeting capabilities. “HERTI is further along in terms of a development program, and we’ve got systems that are close to where you’d want them for an operational system. Built into Taranis is a similar style of autonomous system. It’s subtly different in terms of some of the functions, but it’s got the same basic principles embedded within it,” Allam says.

Developments in several other types of unmanned aerial vehicles (UAVs) contributed to the Taranis program. The Taranis UCAV shares many of the design and system components of the Raven (t) and Corax (center) UCAV demonstrators. The new aircraft’s autonomous flight control software is similar to those of the High Endurance Rapid Technology Insertion, or HERTI, reconnaissance UAV program, but it is configured for combat operations.
As part of the Taranis program, BAE Systems is developing a command-and-control ground infrastructure. An important feature of the effort is that engineers are developing and testing new technologies only where they are absolutely necessary. Some of the systems for the aircraft and its ground control reuse existing technology, whereas other systems feature new software and hardware. “That’s the overall style of the program. We willingly develop where we need to,” Allam states. “We’ll reuse where we can and where it’s most cost effective for the demonstration.”

Allam adds that the integration of various new and existing software and hardware systems is an important feature of the Taranis program. “The vehicle gets the press, but it’s really about the system design. It’s even more important than the vehicle design,” he maintains.

Because it is envisioned as a deep-penetration, high-endurance aircraft, Taranis has several unique capabilities built into its communications and datalink systems. Allam could not comment about the specifics of the UCAV’s communications capabilities, but he shares that bandwidth control is an important feature of the system design. Designers are currently working on the management and integration systems for the communications package. BAE Systems engineers also are neutral in terms of selecting a specific type of datalink, a decision that allows for more flexibility in choosing new equipment. “We don’t really care what the datalink type is. We’ll use ones that are available now, and we’ll upgrade as we go forward. For us, it’s more about the architecture and management of communications and for the clever integration of technologies that go with them,” says Allam.

Allam notes that the integration of payload systems is an important part of the program. He emphasizes that the large, jet-powered UCAV is an experimental aircraft. The goal of the program is to develop and test a variety of technologies in one platform to allow the MOD to make a decision about moving toward an operational capability.

The MOD requires a platform with low observability in terms of radar signature and heat emissions. Taranis’ stealthy design is a necessity for deep-penetration missions. Another capability that may be included in future versions of Taranis or a new UCAV design is aerial refueling. Allam says that a mid-air refueling capability would provide the platform with additional operational flexibility, but he is unsure if such a feature will be included in the current systems design.

A key challenge for the program is integrating sensors and autonomy systems to create a situational awareness picture for the aircraft that is flexible, safe and qualified for military missions. “The technology looks doable. Integrating it properly and being able to clear it are the things that we’re focused on,” he says.

The program’s engineers also are designing autonomous navigation systems that meet the United Kingdom’s UAV requirements for operating in controlled airspace and with other aircraft when necessary. Allam explains that from a systems design perspective, integrating this capability into a platform that operates autonomously and with other manned systems is a challenge.

Another important function being developed for both Taranis and HERTI is the ability for the entire system to operate autonomously for a specific mission. Allam says that part of the UCAV’s autonomy and situational awareness functions is performed by onboard processors and software algorithms managing sensor data. Another systems design focus includes converting sensor data into a usable form and developing an autonomous capability to identify potential targets based on this information.

After a target is located and identified, the system must interface with an operator at the specific level designated by that operator. The exact level of human-machine communication can vary from the aircraft-only transmitting data when necessary to preserve bandwidth or maintain secrecy to streaming real-time sensor information to the operator and asking for a decision. “That whole chain of command and loop is something that is an important part of the program, and that’s taking our intellectual effort in terms of autonomous system design as we go forward,” Allam says.

Allam notes that the first drop of Taranis’ fundamental system design already has occurred, and coding and testing are underway and are scheduled for completion by the end of the year. Metal cutting for the UCAV will begin in late fall with assembly taking place in 2008. The second phase of the autonomous architecture, with bench testing and refining, also will take place in 2008. Flight tests are scheduled for 2009. The flight and assessment phase of the Taranis program is scheduled for 2010. Based on the aircraft’s performance, the MOD will decide in 2011 whether to continue the program.

Web Resources
United Kingdom Ministry of Defence:
BAE Systems:


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