Vetronics for Fighting Vehicles.
The exact meaning of the word `vetronics' depends on your profession, so if invited to attend a conference or exhibition on the subject, check what is being discussed or shown. Get it wrong, and you run the risk of meeting the person who gives your dog or cat its annual vaccination! To the military, however, vetronics is a subject far removed from the world of the veterinarian. Just as the words `aviation electronics' led to the coining of a new word `avionics', the growing number of electronic units to be found inside the latest generation of AFVs has caused the coining of the word `vetronics'. Whether the military or the veterinarians were the first to coin the word is a matter of debate, but this article will be devoted to military electronics.
Vetronics is becoming a feature of both many new military vehicles and upgrades to existing vehicles. It needs to be defined carefully. Are the fire-control, navigation and communication systems of a vehicle examples of vetronics? Your nearest friendly marketing representative would probably insist that they are, but there is a more critical school of thought which says that a vetronics system consists of several sensors and subsystems integrated together to provide a whole which is very much greater than the sum of its individual parts.
In this broader sense, the architecture of the vetronics system provides the following facilities:
* data control and distribution
* computer resources
* crew controls and displays
* power generation and management.
The crew controls and displays subsystem is the most visible part of a vetronics system; they provide the critical soldier-machine interface on which the fighting efficiency of the vehicle depends, can involve reconfigurable crew stations and multifunction controls to interface with many vehicle sensors and subsystems and allow tasks to be reassigned among the crew members in the event of hardware failures.
Behind the scenes, the data control and distribution subsystem distributes digital data, video, audio and electrical control signals throughout the vehicle. The computer resources subsystem provides distributed data processing and control capabilities for the various subsystems, while the power generation and management subsystem generates and distributes electrical power to all subsystems of the vehicle.
First the Radio
The first item of electronics to be used in an armoured fighting vehicle was, of course, the radio; until well after the Second World War, the Soviet Union regarded even a radio as a luxury for all but commanders' tanks. Electrical gun stabilisation, then fire-control systems of ever-growing complexity gradually increased the amount of electronics within the tank, but not until the last decade or so have laser-warning receivers and infrared/electro-optical jammers added a significantly extra increased demand for internal space, electrical power, control and display space and crew attention.
Night sights, stabilised sights, complex fire control systems allowing `hunter/killer' operation, and land navigation systems consumed yet more space and power, and required yet more attention from the crew.
The traditional method of housing extra displays and controls into an armoured fighting vehicle was to fit them wherever space was available. The price paid for such an approach was reduced efficiency. A classic example was the turret of the British Chieftain main battle tank. Retained with little change in the follow-on Challenger 1, this may have been high-technology when the Chieftain was first fielded, but by the 1980s was hopelessly outclassed when Challenger 1 crews faced Leopard 2 and M1 Abrams tanks in Nato gunnery competitions.
In the past, tanks have relied on their armour for survival. Experience during Desert Storm showed that Western tanks could survive projectile hits, but the larger numbers of knocked-out Iraqi T-72s which littered the battlefield showed that to rely on armour protection alone would not be a wise course for the future. Improved situational awareness would be necessary for survival on the battlefields of tomorrow -- and that requires new sensors and displays. The arrival of new hardware such as digital battle-management systems added yet more functionality to the AFV, but threatened to make yet greater demands for space, amps and attention.
Digesting the Information
While the number of electronic systems on the modern vehicle is increasing, so also is the amount of information that must flow within and between the individual systems. Concurrently, features such as imaging, target recognition and target tracking are altering the nature of that information. It is no longer enough to be able to pass video information from one system to another; video data may need to be converted from analogue to digital form to be fully exploited my modern digital signal processing techniques. Throughout the vehicle, the output from sensors is being converted from analogue to digital at an early stage, a trend which can only increase in the future, as well as the amount of data being transferred and the rate at which it must be sampled. Future system architectures must be able to handle these demands, and provide ever-growing levels of processing power.
The growing digitisation of weapon systems has encouraged the use of embedded simulation for training purposes, a trend which the vetronics designer must accommodate. An AFV with an embedded simulation system would present its crew with a simulated `virtual world' which can be used not only for training and mission-rehearsal but also for planning tasks such as the evaluation of proposed tactics (see Embedded Simulation, Armada 6/2000, page 10).
Virtual training can be done in any weather, consumes no fuel, makes no damage to the environment, and does not leave litter, expended ammunition, or `dud' rounds to be cleared up. Being computer-generated, the `enemy' can easily be reprogrammed to create new tactics or even new equipment.
The US Army's Tank-Automotive Research, Development and Engineering Center Vetronics Simulation Facility team has been exploring the usefulness of embedded simulation and is developing a system for armoured fighting vehicles. Efforts have been focussed on a low cost "B-Kit" consisting of off-the-shelf personal computer-compatible hardware packaged into a ruggedised box and designed to be integrated with several vehicle architectures.
Incorporating embedded training into legacy and future combat systems will not be cheap. Despite the potential savings mentioned above, embedded simulation may not be cost-effective if used only for training, but if it is also used for mission rehearsal and battlefield visualisation as well as a tool for simulation-based acquisition the cost savings become worthwhile.
To be combat-effective, an `electronics-heavy' AFV needs a high level of integration which will reduce the number of `black boxes' and the density of the `rat's nest' of electrical cabling within the turret and hull, and allow the crew to manage the new electronics using a smaller number of display and control units.
This concept of integrating the vehicle's electronic systems was embraced by the US Army, which was keen to take advantage of the latest developments in sensors and command and control technology and by the French Army which was developing its next-generation Leclerc tank. Both nations realised that blending these new technologies into an effective combat platform would require a much-improved human/machine interface (HMI) exploiting the latest developments in display and control technology.
Hot, Tight Squeeze
Fitting electronic systems into an armoured fighting vehicle is not easy. For a start, the hardware must cope with high levels of shock and vibration. Then there is the problem of temperature. It's often hot inside an armoured fighting vehicle, with the engine, electronics and crew all adding their individual contributions to a vehicle which may be operating with all hatches closed.
The crew compartment of any tank can become excessively hot when the vehicle is operating in desert conditions. For example, on the basic M1A2, when the outside temperature is 51 [degrees] C (125 [degrees] F), the temperature at the commander's station rises to around 57 [degrees] C (134 [degrees] F), limiting the commander's endurance to an estimated 91 minutes. This was to prove a potential problem in the 1990s when the US Army planned its M1A2 System Enhancement Package (Sep). The Sep would add new electronic systems to the vehicle, and engineers realised that as a result of the extra heat generated by new systems, the internal temperature could rise to 62.8 [degrees] C (145 [degrees] F), reducing the commander's endurance to less than 80 minutes. This high temperature would not only reduce crew performance, but would have forced the use of costly mil-spec components, thus driving up hardware costs.
To prevent its overheating, General Dynamics Land Systems included a Thermal Management System (TMS) in the upgraded M1A2. This cools the crew compartment to around 30 [degrees] C (85 [degrees] F) when the outside air temperature is 51 [degrees] C (125 [degrees] F), and is expected to almost double the crew endurance from that of a standard M1A2.
Humidity can also prove a problem, most notably if vehicles must deploy in tropical regions. It is a traditional enemy of both optics and electronics, and must be taken into account, particularly if vehicles are in storage. Visiting one of the early Leclerc units, Armada International was surprised to see that each tank was housed in an individual environmentally-controlled flexible cocoon. If France's new tank required so much pampering, we asked, what use would it be in combat? Tanks in daily use did not require such precautions, we were told.
The quality of the DC electrical supply within the vehicle may also leave much to be desired. Potential problems include severe voltage surges, spikes and dips.
If this mechanical or electrical environment was not enough to induce grey hairs on electronics designers, there are also the severe mechanical restraints caused by the limited space within the hull. This is particularly a problem when upgrading an existing vehicle and is exacerbated in the case of tanks of Russian or Ukrainian origin, the interiors of which are notoriously cramped even by Western standards. The turret of a British Army Chieftain -- an ergonomic slum by modern standards -- is positively spacious compared with that of the T-62, its Soviet-era counterpart. Several years ago, Armada International was shown Western hardware designed for retrofitting to Russian-designed tanks. One particular sub-unit had a most odd shape, the result of having to be designed to fit within the only space available in the area within the vehicle were its function required it to be mounted.
Even in cases where new electronics are being installed in place of obsolete hardware, the customer may insist that the replacement fit within the space taken up by its predecessor.
High-Speed Databus Needed
Life is not much easier for vetronics engineers if their system is for a vehicle that is still being designed. The inevitable demand for space from the designers of all sub-systems and from the crews who will have to operate the vehicle is made even more severe by the need to reduce the silhouette, and thus the vulnerability to detection and attack, of the final vehicle.
Creation of an integrated vetronics suite requires the use of a system architecture which will define the overall structure of the system, define its internal protocols and specify its internal and external interfaces. An efficient architecture will also allow changes such as new or improved sensors or revised software offering new functionality to be made at relatively low cost.
In most cases, this architecture is based on an open system. Designers of digital systems define an open system as being one which uses:
* well-defined, widely used, non-proprietary interfaces and protocols
* industrially recognised standards
* interfaces which will allow the addition of new or improved system enhancements.
Systems based on open standards can be easily upgraded to provide higher performance or additional capabilities by the use of improved or newly-developed hardware. In the civilian world, the best example of this approach is the personal computer. In its most ubiquitous form as found in many offices, this is based on an architecture drawn up some two decades ago by IBM, and subsequently modified by the evolving small computer industry to take account of technological process. Adding more memory, a faster processor, or even new functions such as speech recognition is a matter of installing easily available hardware of software offered by a wide range of companies.
A key element in handling the flow of electronic data within a future AFV will be the use of an efficient databus. This will handle the peak data flows, distributing the data around the vehicle in real-time, and allow the use of a distributed computer architecture whose built-in redundancy will distribute (and if the event of damage or failures, reassign) key system functions, reducing overall vulnerability.
Like avionics suites, vetronics suites are often based on some form of standard databus. Given its widespread use of aircraft and ships, the MIL-STD-1553 was an obvious choice. The US Army's M1A2 Abrams Sep uses what is termed a Utility Bus. This is a control bus similar to the proven MIL-STD 1553 standard, but using the EIA-485 electrical specification.
MIL-STD-1553 is an established and reliable data bus, and has been in service for more than two decades, with hardware available to cope with the harshest environments that a manned platform is likely to experience. However it can only handle data rates of up to 1 Mbit/sec, which may be too slow to manage the data, audio and video information rates of the future.
In 1982, France adopted the Digibus standard for land, sea and air use, so it was logical that this should form the digital `backbone' of the Leclerc MBT. But this may also be too slow to meet future requirements.
The International High-Speed Data Bus User Group is conducting experimental work to identify a potential long-term replacement databus able to meet future data rates. The chosen solution will probably be based on commercial off-the-shelf technology.
There are several potential candidates, such as Fibre Channel, FDDI [Fibre-Distributed Data Interface], Ethernet, Firewire/IEEE 1394, ATM, and Universal Serial Bus (USB). Some of these come from the commercial computer world, but although being adopted on a growing scale lack some of the features needed in a military databus. For example, the Firewire/IEEE 1394 bus can handle from 100 to 400 Mbit/sec and has valuable features such as the ability to hot-swap hardware, but it is intended for use in office environments and over ranges of only a few tens of metres. Universal Serial Bus (USB) is another protocol well suited to the office environment but its maximum data rate of 12Mbit/sec is too slow for future military use.
Local area systems such as Ethernet are also widely used by the business community, but the cry of "the network is down" heard in many offices shows that these may lack the robustness needed for mission-critical applications.
Fibre Distributed Data Interface (FDDI) is capable of data rates of up to 100 Mbit/sec. It is a mature technology and has already been selected for applications such as the US Navy's Trident submarines, the Lan on the Royal Swedish Navy's new Visby class stealth corvettes and the SSCI platform management-system on the French Navy's aircraft carrier Charles de Gaulle.
However, that 100 Mbit/sec maximum rate could one day prove a bottleneck. Once again the world of the personal computer provides an obvious analogy. When IBM designed the original Personal Computer in the early 1980s, the basic architecture supported up to 640 kilobytes of memory, ten times that of its contemporaries. IBM engineers thought they were being bold in planning for such a large amount of memory, but today's PC is likely to have at least 64 megabytes of memory.
Asynchronous Transfer Mode (ATM) is widely used in civil telecommunications and is being adopted on a growing scale for military communications. Implemented in copper wire, ATM can handle date rates of 155 Mbit/sec, but on optical fibre the rate leaps to 622 Mbit/sec.
ATM was primarily designed for voice transmission, a field in which the loss of a packet may be undetectable to the human ear. Dropping a packet from a data block is more serious, but the ATM protocols are being enhanced to support more reliable data transmission. Another problem is that is has high latency. Telecommunications systems can cope with 100 microsecond latencies, but mission-critical military systems may need a faster response time.
ATM has been adopted for some shipboard applications, including the Sewaco XI combat direction system of the Royal Netherlands Navy's new De Zeven Provincien class frigates, and the dual-redundant combat system data bus of Germany's planned new F124 frigates. It is also used by the US Navy's Information Technology for the 21st century programme, the German Luftwaffe's AutoFuFmNLw) military data-communications network and the communications network to be installed for Denmark's modernised MIM-23 Hawk (Homing All the Way Killer) surface-to-air missile system.
Fibre Channel Arbitrated Loop (FC-AL) offers rates of 100 Mbit/sec scaleable to 1 Gbit/sec, plus low latency, and in the commercial world is supported by all major vendors of workstations and servers. In the military world it has already been chosen for the E-3 Sentry, B-1 Lancer, F/A-18 Hornet and the next-generation Joint Strike Fighter (JSF).
Writing last year in Cots Journal, senior editor Chris Ciufo reported that "It is expected that FC-AE [the Fibre Channel Avionics Environment standard for military applications] will be used in next-generation and some avionics upgrades to replace the ageing and slow MIL-STD-1553B data bus. And Fibre Channel's new low-cost long-haul fibre standards are sure to be considered as an alternative to Spawar's Safenet [The US Navy Space & Naval Warfare Systems Command's local area network] to replace the miles of heavy copper cables weighing down modern war ships."
Another new technology attracting the attention of vetronics designers is that of flat-panel displays (FPDs) able to replace bulky and power-hungry cathode-ray tube (CRT) monitors. As with databuses, there is a strong move towards the use of Cots technology. The US Congress has asked the Department of Defense to study the tradeoffs made in acquiring `consumer-grade' displays rather than units custom-designed to meet military requirements. The resulting study showed that ruggedised consumer-grade FPDs could meet the environmental requirements for a broad range of military applications, including army ground vehicles.
Such modified off-the-shelf (Mots) hardware is being adopted on a growing scale, and may become easier as high volume manufacturers of commercial displays move into non-computer areas such as the industrial, medical and transportation markets to increase their sales. These non-military users may have requirements closer to those of the military than to those of the laptop computer industry. Mots displays may be inexpensive by military standards, but there is concern in the USA that the main suppliers of commercial FPDs are in foreign countries, which raises questions over the wisdom of becoming dependant on overseas suppliers in the long term.
In Europe, the major suppliers of ruggedised displays are Barco Display Systems in Belgium, Lynwood in Britain and Thomson-CSF in France (which may well have been incorporated under Thales -- the new name of the French company -- since these lines were written). In June of last year, Barco was chosen to supply its Vector display for use on the wheeled Multi Role Armoured Vehicle (Mrav). The Vector system consists of rugged flat-panel displays, a control module and human-machine interface software. It uses a split design which allows the display module to be located up to five metres from the video-control module. This allows easier integration into vehicles or consoles.
The configuration chosen for the Mrav consists of two DM118 seven-inch displays which will provide video and thermal images to the crew. Data retrieved from the vehicle's ring-redundant Can-Bus will be displayed on screen. This will consist of images plus a graphics overlay and other information as well as data from the Vehicle Management System.
In the first quarter of 2001, Barco will deliver an initial series of 24 display systems to MaK, one of the companies that make up the Artec consortium responsible for developing and manufacturing the Mrav.
In the past, designers of vetronics often used custom-designed military hardware. This may have met every environmental specification that the end-user could desire, but in performance terms custom-designed military hardware could be several years behind the equivalent civil hardware, and less easy to integrate.
Today, major computer component manufacturers such as Intel are less interested in developing military-specification hardware, and are repackaging commercial components to operate over the extended temperature ranges typical of military applications.
Cots hardware and software are being exploited to hold down the cost of vetronics. The VMEbus standard is being used in many vetronics systems, and Cots VMEbus products are being used in vehicle applications such as the US Army's M1A2 Abrams Sep, and in other military applications such as the US Navy's Co-operative Engagement Capability (CEC) system.
The M1A2 Abrams Sep is a classic example of how Cots can be used in a vetronics system. When the M1A2 was developed, its designers provided a good reserve of computer processing throughput, only to see this almost completely absorbed by design changes prior to the tank entering service. For the Sep programme, General Dynamics opted to use Cots, and the company DY4 devised a configuration based on a second-generation PowerPC general-purpose processor (GPP) derived from an off-the-shelf product.
Two GPPs in varying mezzanine configurations are used in the M1A2 Sep Mission Processor Unit, Turret Mission Unit and Commander's Electronic Unit. These three units are the primary processing nodes in the overall system.
The resulting system will administer a new level of complexity to the M1A2, yet is intended to offer improved availability. This is expected to come from:
* an improved energy distribution system to handle higher-power electronics
* the thermal management system, which keeps the internal operating temperature of the tank within respectable levels
* improved reliability of low-level components (such as integrated circuits) and high-level components (such as displays)
* improved component operation environment; including temperature, shock, vibration, dust and EMF
* embedded simulators for training purposes
* embedded documentation in the form of online help
* a diagnostic expert system.
Under programmes such as the Crewman's Associate ATD and Intravehicle Electronics Suite STOs, the US Army has studied much of the vetronics technology needed for the Future Combat System (FCS) family of AFVs. The resulting vetronics system will undoubtedly set new levels in integration and combat effectiveness.
By fiscal year 2004, the Advanced Electronics for Future Combat System programme is intended to develop an integrated ultra-high-power electronics package and crew station technologies for the Future Combat Systems (FCS) Integrated Technology Demonstrator. Specific technologies to be integrated include helmet-mounted displays, head trackers, panoramic displays, cognitive decision aids, load-management algorithms, automated route planning and a power-management system able to meet the demands of an electromagnetic gun, electromagnetic armour and electric drive.
Other nations who are major manufacturers of AFVs are more tight-lipped than the US Army on the subject of vetronics, but all are actively researching the electronic systems planned for future vehicles. France is already using an open-architecture vetronics system for the 120 mm-armed T-21 turret which it is studying in conjunction with the Slovakian company DMD as a possible upgrade for the T-72 main battle tank, while Vickers Defence Systems adopted an open architecture for the VME-based vetronics system it is offering for armoured fighting vehicles.
Research facilities such as the British Defence Evaluation and Research Agency's crew-station demonstration facility (CSDF2) are being used to assess advanced crew-station technologies for future vehicles. Crew-station hardware and software modules are fully reconfigurable and vehicle simulation can be modified to represent any armoured fighting vehicle, complete with simulated episcope, mast sensor and turret sensor views, and both daylight television and thermal images.
Such advanced technologies will not become a monopoly of the United States and Western Europe. The recent merger between Elbit Systems and El-Op creates a company whose product line and expertise includes sensors, fire-control systems, battle-management systems and gun-turret drives. Nations such as Russia, the Ukraine and China are also likely to turn to Cots solutions for the problems of keeping their AFVs combat-effective. The marriage between tanks and 'black boxes' is not likely to end in divorce.
* "The growing complexity of the electronic systems in the modern AFV creates new integration challenges"
* "Vetronics offers the chance to combine these systems into a combat-effective system of systems"
* "Open architecture design approaches allow the use of commercial solutions, and make it easier to upgrade the vehicle"
* "The high data rates of future AFVs will require a faster databus than the long-established MIL-STD 1553."
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|Date:||Feb 1, 2001|
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