Microwave Journal
www.microwavejournal.com/articles/1337-military-microwaves-2006-current-viewpoints-on-air-defense-systems

Military Microwaves 2006 — Current Viewpoints on Air Defense Systems

June 1, 2006

The editors of Microwave Journal® and Journal of Electronic Defense interviewed some key executive and military leaders in the markets that we serve, both in the US as well as in Europe. Selected questions and answers from those interviews are presented below. We would like to thank the participants who took the time and effort to present their views. As expected there are significant differences in the US and European approaches to system development. We hope you find the responses to be informative.


Mark Hebeisen

Mark Hebeisen
Vice President
Marketing & Business Development
Endwave Corp.

MWJ: Looking at the air defense programs in Europe and the United States, what are the key areas of development?

MH: Endwave Defense Systems is actively involved as an RF subsystem supplier on a number of current and future Air Defense Systems (ADS). These opportunities span a wide range of capabilities and platforms, from fighter jet aircraft, attack helicopters, unmanned aerial vehicles (UAV), and other airborne warning and surveillance applications. At a time when governments are struggling to dedicate the necessary funding required to secure the homeland and fight a long global war on terror, the Pentagon is pushing for “military transformation” — one that signals a shift away from large stove-piped defense platforms towards creating more agile, mobile forces that work in concert and are linked with advanced wireless communications networks. The fight today is, first and foremost, for communication superiority.

In the near-term, it is apparent from the QDR and US defense budget released earlier this year that major defense programs like F/A-22 Raptor, F-35 Joint Strike Fighter and Future Combat Systems are all continuing. Contracts favoring upgrades to extend the range or increase the payload of existing air defense platforms are more likely than replacing them with completely new systems — so adaptability is a common theme. Programs dedicated to only one military branch will be a distant memory as the resounding theme of interoperability within a joint “future force” is being voiced by the Pentagon. Key areas of development will shift the Department of Defense’s (DoD) attention from conventional fighting techniques to unconventional irregular warfare. Endwave sees tremendous opportunities for missiles and anti-missile systems, smart munitions, and UAVs for both surveillance and strike capability. Both manned and unmanned programs in Intelligence, Surveillance and Reconnaissance (ISR) applications abound. An excerpt from the QDR cited, “the ability of the future force to establish an ‘unblinking eye’ over the battlespace through persistent surveillance will be instrumental to conducting effective joint operations.”

MWJ: Describe how the development of wireless networking technology, such as data links, is making integrated ADS more effective and survivable.

MH: Taking critical battlefield information from multiple sensors amongst a host of different platforms — and making that information available to all members of the joint future force, will create a “network-centric” military operation. As an example of the power of connectivity, many of the UAV missions conducted in the Middle East were flown remotely by pilots in Nevada, with real-time communications from forces on the battlefield to direct the mission. The enabler for such information connectivity lies in high capacity directional data links in order to put the right information real-time directly in the hands of combatant commanders. As such, these data links are deemed necessary in order for the United States’ UAV strategy to pay off, which calls for a near doubling of the UAV coverage. Recently, tactical data links were used to demonstrate airborne interoperability between US Apache attack helicopters and Hunter UAVs, as further evidence that the network-centric military force is not so far away.

MWJ: What changes in radar systems are needed to support the new generation of ADS?

MH: Synthetic aperture radars (SAR) at millimeter-wave frequencies are being incorporated onto many UAV platforms in conjunction with optical imaging sensors to provide high resolution imaging around the clock or during harsh weather environments. Furthermore, phased-array radars are becoming an increasingly popular choice in ADS, due to their ability to steer the antenna beam in a near-instantaneous fashion — improving accuracy and precision, as well as the ability to track more targets simultaneously. These radars often use thousands of radiating antenna elements, each driven by a T/R module with precise control of gain and phase amongst elements.

There is certainly a trend towards the increased use of microwave and millimeter-wave frequencies — due in large part to their unique ability to carry large amounts of data, to provide higher resolution for radar systems, to penetrate certain structures and to provide solutions that are small, light-weight and high performance. In addition, we’ve seen numerous instances where millimeter-wave radars are necessary to see through sand storms in the Middle East for automatic landing guidance (ALG) systems on attack helicopters and other fighter aircraft in ADS.

MWJ: Are there any applications for conventional antenna systems or will all new radars be phased array?

MH: We see opportunities for both conventional and phased-array radars in future ADS. Given the DoD emphasis on budget trimming, each radar platform has a risk vs. reward analysis to be done. As a hardware supplier for a major development program in 2005, we witnessed a shift away from a phased-array approach used in the engineering development models to a more conventional radar-trading performance for a lower overall cost. But over time, as innovative technologies are introduced to lower the costs of these advanced radar systems, we believe phased arrays will be the predominant choice in the industry.

MWJ: What advances in sensor fusion are required?

MH: Sensor fusion refers to the ability to collect, distribute, process and quickly respond to intelligence data coming in from multiple sensors — all in an effort to aid decision-makers in battlefield coordination and to anticipate the actions of our adversaries. In future Air Defense Systems, the assimilation of sensor inputs will require access to intelligence data originating from both inside and outside of the battlespace — so a seamless integration of inputs from tactical, terrestrial and satellite communications sources will be necessary. Imagine being able to simultaneously strike thousands of enemy targets at remote locations around the globe, or the ability to instantaneously re-target cruise missiles and bomber payloads mid-flight while moving allied troops out of harms way. That’s what the future air defense capability looks like. Given the large amount of data to be shared amongst many mobile combatant commanders, and the speed in which that information needs to be pushed down to this large group of users, products and platforms that enable secure wireless broadband data distribution will be in high demand.

MWJ: What technologies will fuel the growth of ADS over the next five to 10 years and to what extent?

MH: New threats require new battlefield tactics, and new battlefield tactics will require “disruptive” technologies to break through previous cost vs. performance barriers and allow system designers to pack more complex hardware into tighter form-factors than ever before. In high frequency subsystems, consistency and cost are two of the most common challenges encountered. Advances in both MMIC and MMIC-alternative technologies are paving the way for tuneless low cost T/R modules that form the heart of future radars and communication links. Multilithic Microsystems® (MLMS) is an advanced circuit technology using flip-chip and electromagnetic coupling methods to minimize expensive semiconductor real estate while eliminating lengthy interconnects and their related variability. MLMS moves passive circuitry onto an inexpensive proprietary substrate that processes with the ease of silicon, yet works past 100 GHz. Only the discrete active devices remain, which are then flip-mounted on top of the MLMS substrate. Mixed device technologies like SiGe, GaAs and InP can be utilized to increase functionality and optimize performance. The result is a true “system on a chip” with no bondwires in the RF path — and at 30% less cost than a MMIC-based solution.

With phased-array radars often employing thousands of T/R modules, the mechanical packaging associated with high frequency electronics is often a major contributor to the overall cost of ADS platforms. Conventional millimeter-wave thinking is rooted in the belief that module housings have to be fabricated utilizing costly machining and plating techniques. In contrast, Epsilon® Packaging is a multi-layer substrate and module package, all in one. It replaces costly and heavy weight metal mechanicals with metallized FR-4 and injection molded metallized plastics. The Epsilon Packaging approach includes revolutionary mixed technology integration, allowing chip-on-board and surface-mount technology components to co-exist, thus easing assembly and reducing cost. The end result is a package with no machined metal parts, making it light and mass producible, with efficient heat extraction.

In summary, the opportunities in fighter and surveillance aircraft, missiles, smart munitions and UAVs all demand technologies that aid the “lighter, cheaper, faster” requirements of these future Air Defense Systems. To learn more about Endwave’s response to these challenges, please visit www.endwave.com.


Bradley W. Pietras
Missile Defense Business Development Mgr.
Lockheed Martin MS2-Radar Systems
Syracuse, NY

David Ponticello
Radar Systems Chief
Lockheed Martin MS2-Radar Systems
Syracuse, NY

JED: Looking at the air defense programs in Europe and the United States, what are the key areas of development?

LOCK: Lockheed Martin’s primary air defense programs impacting both the US and European markets include the Theater High-Altitude Area Defense (THAAD) system; the Medium Extended Air Defense System (MEADS); the Patriot PAC-3 and PAC-3 Missile Segment Enhancement (MSE); and the High-Altitude Airship (HAA) program, which will provide greater situational awareness against low-flying threats such as cruise missiles. Another important program is the US Army’s Counter-Rocket, Artillery and Mortar (C-RAM) program [prime: Northrop Grumman], which ties a Firefinder counter-battery radar with a modified Phalanx gun system. This system has already been deployed to Iraq.

It is clear that defense against a wide range of missile and projectile threats, from ballistic missiles to mortars covering all altitudes and ranges are required to ensure coverage. Armed forces are working on protecting high-value assets and individual personnel from high-tech and low-tech threats.

JED: Describe how the development of wireless networking technology, such as data links, is making integrated ADS more effective and survivable.

LOCK: Air and missile defense (AMD) systems are moving to “plug-and-fight” architectures that integrate multiple sensors and shooters into distributed, survivable networks. Such an architecture is more survivable because individual components can be unplugged, moved and plugged back in without taking the whole network offline. The network is also more resistant to damage.

Technological advances have enabled a significant reduction in the size of equipment while at the same time providing increased capability, higher reliability and a reduced logistics burden. Technology has also taken us from the analog world to predominantly a digital world. This enables software-only upgrades and multiple modes of radar operation. The different modes could be looking for air-breathing targets or tactical ballistic missiles. The radar may be operating in a rotating 360-degree surveillance mode in one situation and in a sectorized, longer-range mode in another if the goal is to get high-range resolution data on a target. Phased-array radar technology seems to provide the versatility required for today’s and tomorrow’s AMD architectures.

Technology also enables the integration of a multitude of acquisition and fire control sensors. The ultimate goal is the creation of a single integrated air picture (SIAP).

JED: What changes in radar systems are needed to support the new generation of ADS?

LOCK: The capabilities of next generation air defense systems are driven by expanding missions, advanced threats and operation in hostile manmade environments. Radar system improvements required to support new Air Defense Systems include:

  • Increased sensitivity to detect smaller targets at longer ranges

  • High stability digitally-controlled receivers and exciters provide waveform flexibility with improved clutter suppression

  • Digital beam forming provides additional radar resources and improved jamming and EMI suppression.

  • High mobility and transportability

  • Remote operation

  • Target classification, discrimination and identification

  • Interoperability across services for joint operations and international coalitions

These radar system improvements provide increased capability to support next generation Air Defense Systems.

JED: Are there any applications for conventional antenna systems or will all new radars be phased array?

LOCK: As new radars operate in increasingly complex stressing environments, the advantages of phased-array radars will be required. Phased arrays provide an agile beam and enable multi-function radars. Phased arrays enable the dynamic control of radar time, allowing radar beams to be priority scheduled. This flexibility allows the application of radar resources and track update rates to vary based on target priority. In addition, phased arrays enable increased radar track capacities. The use of conventional antenna systems is limited to applications where an agile beam is not required or weight and cost are primary system constraints.

JED: What advances in sensor fusion are required?

LOCK: The ability to fuse sensor data from multiple sensors can increase the fidelity of the air defense picture. The advances required to improve sensor fusion performance are higher bandwidth sensor networks, improved sensor registration and track correlation capabilities. This is especially true with mobile sensors operating in target-rich high-clutter environments. Additionally, networks allow sharing of data from one sensor or weapon system with another system enabling engage on remote capabilities. Target registration and de-confliction along with robust target classification, discrimination, and identification are critical elements of any network-centric air defense system.

European Perspective

Political, social, demographic and economic factors are key influences on the development and direction of European defence and security, with the challenge being to adapt and prosper within this changing environment. To meet these challenges both governments and commercial enterprise are tending towards a collective European approach. Particular European Union initiatives include the development of a European Security Research Programme (ESRP), as part of the 7th EU Research Framework Programme, a key element of which is the Preparatory Action for Security Research (PASR). This overview article specifically addresses the development of Air Defence Systems and here the Medium Extended Air Defence System (MEADS) is being designed to be effective against enemy aircraft, which will incorporate its own three-radar set, along with networked communications. Its broader goal being an open architecture system that can plug into larger defensive systems along with shorter-range systems. Commercially, the AeroSpace and Defence Industries Association of Europe (ASD), formed in 2004, represents industry in Europe in all matters of common interest with the objective of promoting and supporting competitive development both on a European level and transnationally. The following interviews testify to the ongoing development work being carried out in Europe particularly concerning the changing operational needs of society and the increasing capabilities offered by technology. Asymmetric warfare, network-enabled capabilities and global security are all addressed with particular attention being paid to wireless networking technology, sensor fusion and phased-array radar.


Gilles Martin

Gilles Martin
Marketing Director
Chelton Telecom & Microwave — a Cobham Avionics & Surveillance Division company

MWJ: Looking at the air defence programmes in Europe and the United States, what are the key areas of development?

GM: From a European perspective I see the areas of development of air defence programmes as being active phased arrays, satellite data communications, UAVs, identification systems, missiles and antimissiles. There is unquestionably continuing progress towards phased arrays in general in the air defence market and as far as phased-array antennas are concerned several major European countries are becoming equipped. Their motivation being low power consumption and increased radar power.

Satellite data communications also play a key role in Air Defence Systems. Via integrated radio links, they are used for both localisation and observation, with information relayed from ground bases and aircraft creating a clear understanding of what is happening on the battlefield. Battlefield knowledge is also driven by the development of UAVs, drones and identification (IFF and BIF). We should also mention missiles and antimissiles — the Future Surface-to-Air Family (FSAF) programme for instance.

MWJ: Describe how the development of wireless networking technology, such as data links, is making integrated ADS more effective and survivable?

GM: ADS will certainly benefit from all of the major achievements made in the telecommunication sector, such as the processing and treatment of information, which can help secure military systems. Telecommunications are synonymous with efficiency and speed, which leads to a reduction in costs. The radio mobile (IF band) has also made important strides, such as the improvement in the security of data transmission based on low phase noise PLLs. As a major player in the telecommunications market we share our knowledge with other customers.

MWJ: What changes in radar systems are needed to support the new generation of ADS?

GM: Several areas of amelioration should be considered: mobility (smaller, lighter, reduced consumption), prices and delivery (COTS), the integration of components with regards to specific functions, for instance Circulator + Isolators + Limiter (CIL) assemblies in the RF head with passive and active components, and the optimisation of features. We can envisage an open architecture with standard components that is easy to install.

We should also consider mechanical ruggedness and higher RF EMP handling capability, lower intermodulation products (IM3) like in radio mobile applications, increased power and wider operating bands (higher than 20 percent). And in order to facilitate users in different countries and provide modularity for maintenance why not add a compatible protocol for all systems, which will consequently increase component reproducibility.

MWJ: Are there any applications for conventional antenna systems or will all new radars be phased array?

GM: Phased-array antennas are heading the market but specific applications will use conventional radars like mono-function types such as target radars for territory, area surveillance and control. This is because conventional radars offer invaluable advantages: low cost, easy installation and maintenance, countermeasure capability and network capacity as multiple sensors. Furthermore, if we consider the necessary time to get to market and the long heritage of conventional radars, we can bet they have a long life ahead.

MWJ: What advances in sensor fusion are required?

GM: Sensor fusion is a multi-domain awareness system that uses live information from various sources and as such creates a need for multiple database analysis. Depending of what is requested, various sensors will be designed according to the three modes: cooperative, competitive and complementary modes. Thus, the advances in sensor fusion are complex. Modern weapons platforms on land, at sea and in the air are heavily reliant upon massive computer capability, which continues to improve enormously. This may lead to a combining of sensor functions, which, in turn, may well drive multi-function components and subsystem needs throughout the market, in terms of both software and hardware.

The trend for European system manufacturers to buy black boxes for multifunction applications continues at pace, and it is clear that companies with a poor range of technologies will not be able to stand the natural evolution of the microwave component market into raw subsystem-based entities.

MWJ: What technologies will fuel the growth of ADS over the next five to 10 years and to what extent?

GM: From our point of view, elements or technologies that need to be developed are: integration of discreet elements under functions or modules, higher power capability, miniaturization, weight reduction, MMIC and MEMS in five to 10 years and the integration of new materials (that is, with better power and thermal handling capabilities).


Bernhard Gerwert

Bernhard Gerwert
CEO
EADS Defence Electronics

MWJ: Looking at the air defence programmes in Europe and the United States, what are the key areas of development?

BG: As usual, the key drivers of development are two pronged — firstly, the changing operational needs of the customer and secondly the increasing capabilities offered by technology that are vital in order to meet these needs. On the customer side, we are addressing the changing security needs related to asymmetric warfare, network-enabled capabilities and global security, which together extend the traditional scope of air defence.

This fits perfectly into our activities on the technology side. We are driving forward component technologies and thereby increasing the performance of sensors to meet the future operational threat, for example, MMIC technologies which also reduce the size, weight and power consumption of the HF radar elements. Also, digitization contributes greatly to increasing processing throughput and miniaturization of core components. Not forgetting the development of GaAs materials, enabling the employment of high density T/R modules. This, together with the refinement of algorithms and systems technology, leads to a new generation of radars offering unprecedented capabilities in detecting very small, fast moving objects, tracking individual targets while scanning vast volumes, not to mention automated IFF for avoiding friendly fire and operation modes such as data link.

To give just one example, we have encapsulated all these achievements in the production of thousands of T/R modules for the MEADS Active Electronically Scanning Array (AESA) fire control radar, which is a move towards a new dimension of air defence.

MWJ: Describe how the development of wireless networking technology, such as data links, is making integrated ADS more effective and survivable?

BG: This is basically the overall network-centric story — if you have the situational picture, target data, etc. available to all relevant players in real time then you are able to optimise the positioning of your resources as well as their deployment, thus protecting your forces and improving their overall mission effectiveness.

Apart from sensors gathering the necessary information with the right quality and sensor fusion systems processing it, data links are the cornerstone of this net-centricity. Good examples might be the Multifunctional Information Distribution (MIDS) system introduced in NATO or the increasing use of UAVs, which depend on data links for distribution of reconnaissance data as well as telecommand data uplinks. Also, you need high performance data links for missile mid-course guidance. To achieve sufficient transmission rates and jamming resistance, development is concentrating on high bandwidth microwave technologies, high speed digital signal processors, pencil-beam directional antennas with high precision stabilisation and the overall miniaturization of digital and microwave components.

MWJ: What changes in radar systems are needed to support the new generation of ADS?

BG: As mentioned earlier, radar technology is in a phase of breathtaking dynamism. Therefore, the idea is not to change individual features here and there, but to create a system architecture, which enables the exploitation of all the new opportunities created by progress in component technologies as well as in system technology.

MWJ: Are there any applications for conventional antenna systems or will all new radars be phased array?

BG: Conventional antennas will always find their place alongside active E-scan arrays. This is a question of cost-efficiency relative to the requirements, as well as technical limitations such as size, weight, power consumption and power output. For example, naval radars with conventional antennas for ships below frigate size can very efficiently use existing and solid-state technology to fulfil complex operational requirements while remaining within the limits set by the ships’ sizes and budgets.

MWJ: What advances in sensor fusion are required?

BG: Intelligent multi-source sensor fusion is the fundamental prerequisite for countering new complex threat scenarios with dwindling air defence resources. If you have less air defence units, the capability of the single unit must be higher and, ideally, the coordination between all existing assets must improve. That means sensor fusion systems have to be opened up to a multitude of intelligence sources, which affords increasing transmission and processing capabilities and, above all, highly refined algorithms.

MWJ: What technologies will fuel the growth of ADS over the next five to 10 years and to what extent?

BG: From the electronics point of view, Air Defence Systems will see tremendous progress in terms of component performance due to a combination of digital technologies, further miniaturization based on MMICs and micro-packaging, as well as new materials like GaAs and GaN and related automated production capabilities. To put it simply: Together with innovative systems design this will lead to a reduction of size and weight of radars while increasing tremendously the detection performance and multi-functional capabilities. Even if everybody is talking about ‘new’ threats, radar will remain the only truly all-weather and day/night capable source of intelligence for the foreseeable future with 3D or even 4D capability.


Paul Holbourn

Paul Holbourn
Deputy Capability Director
SELEX Sensors and Airborne Systems

MWJ: Looking at the air defence programmes in Europe and the United States, what are the key areas of development?

PH: The key areas of development are not new but probably have received increased emphasis as a result of recent operational experience. As Air Deployable Systems become more complex, achieving interoperability with friendly forces has become a greater challenge. The need for modern ADS to be deployable, resilient and to integrate with other land and airborne assets has been reinforced by recent experience.

Effective and robust target identification is also a priority. Looking to the future, target threats will change — not only will an ADS have to contend with conventional fixed wing and rotary wing threats, but also handle increasingly ‘difficult’ targets such as low observable Unmanned Aerial Vehicles/Unmanned Combat Aerial Vehicles and long-range cruise missiles.

MWJ: Describe how the development of wireless networking technology, such as data links, is making integrated ADS more effective and survivable?

PH: Networking lies at the heart of an effective ADS. Such a system comprises a combination of weapons, sensors and computing resources. An optimal architecture will deliver battle-winning capability, through the effective integration of the various components and will endow the system with capabilities that would otherwise be unachievable. Networked sensor systems are more resilient and have better performance than the individual components. Radio frequency data links have a particular importance for integrating the elements of a mobile ADS interacting with airborne assets, for example, Airborne Early Warning (AEW), and obviously for communication with missile systems. Increasingly important considerations for the data links are bandwidth, encryption and covertness.

MWJ: What changes in radar systems are needed to support the new generation of ADS?

PH: The introduction of active phased-array radar technology is the disrupter. This technology is now mature and should be regarded as product ready. It offers many interesting new degrees of freedom for the system designer. These encompass enhanced detection and tracking performance, including adaptive beam and energy management, increased Electronic Counter Counter-Measures (ECCM) resistance, covertness and high availability. The challenge for the system architect is to optimally exploit these new features within an integrated multiple sensor system.

MWJ: Are there any applications for conventional antenna systems or will all new radar be phased arrays?

PH: For the customer with demanding operational requirements phased-array-based systems should be considered. Phased-array technology is now mature, and for most applications is affordable and offers considerable performance and Life Cycle Cost advantages. For less demanding applications there is still a market niche for conventional antenna systems. However, over the next 10 years or so, conventional antenna systems will become increasingly marginalized and potentially obsolete in the market place, as phased-array technology becomes more available. Ultimately the cost of a conventional antenna will overtake that of the phased-array equivalent.

MWJ: What advances in sensor fusion are required?

PH: Sensor fusion is a pretty mature technology. However, for it to see the light of day in the field will require ADS architectures to recognise the many benefits that sensor fusion can bring, that is, system resilience, system reconfigurability, graceful degradation, covertness and improved tactical data gathering. By planning for multi-sensor data fusion as an integral feature of the ADS system architecture, the appropriate provision of a flexible data network with distributed processing can be planned.

One active area of research that is of interest to the ADS community is the fusion of data from multiple sources to support high confidence target identification. Such a system would accept data from diverse sources including co-operative Identification Friend or Foe systems, and non-co-operative radar, Electronic Support Measures (ESM) and Electro Optic (EO) sensors to support robust and accurate target identification.

MWJ: What technologies will fuel the growth of ADS over the next five to 10 years and to what extent?

PH: The growth of ADS is not likely to be technology driven, rather it is likely to focus more on consolidating and implementing current technologies within open system architectures, using common standards, which recognise the value of sensor data fusion and the need for networking. Technologies, such as Gallium Arsenide (GaAs), which underpin active phased arrays, are already sufficiently mature to incorporate into product. Emerging III-V semiconductor materials such as Gallium Nitride (GaN) will offer some performance benefits. However, the focus is likely to be on incremental improvement, such as affordability, rather then breakthrough technology.

Thus the key technology is likely to be systems engineering to realise a step change in capability by integrating multiple sensors with distributed processing to deliver operationally effective complex systems. A particularly interesting technology that may come of age is bi-static radar operation using emitters of opportunity.