Ultra-Wide Band Radio Links Boost Indirect Fire Simulation.

Live fire exercises currently are the best option that Army soldiers have for conducting realistic training drills with indirect fire weapons, such as artillery and grenade launchers. But the high cost of munitions and environmental restrictions on live fires have sparked interest in developing technologies that can simulate non-line-of-sight firings in field exercises.

One of the most promising technologies--currently in the early stages of development--is part of the so-called tactical engagement simulations (ATES) program. The project's success is tied to an emerging form of radio communications called ultra-wide band.

Current force-on-force training systems rely on lasers to pair and determine the result of shooter-target engagements. The most widely used today is MILES, which stands for multiple integrated laser engagement system. The MILES 2000 is a laser-based training system in which soldiers fire infrared "bullets" from the same weapons and vehicles that they would use in actual combat. The exercise events and casualties are recorded, replayed and analyzed.

When MILES-equipped soldiers train in a simulated close-combat engagement, laser pulses are sent from a rifle-mounted transmitter to a detection device worn by a soldier from the opposing force. That pulse follows a straight line. MILES, however, has limited use in non-line-of-sight firings--and its capability is degraded by dust and smoke, Army and industry experts said.

The planned development of an advanced dual-mode infantry rifle for the Army, called the objective individual combat weapon (OICW), means that new training capabilities will be needed, beyond what MILES provides, these experts said. The OICW--which could be fielded as early as 2008--has a ranged air-burst capability for 20 mm high energy rounds, in addition to being a conventional rifle. The long-range air-bursting capability is not represented in the MILES system and shooting live OICW rounds will he expensive, at $30 or so apiece. The Army's Simulation, Training and Instrumentation Command (STRI-COM) is looking at the ATES technology as a possible training solution.

The ATES science and technology effort will continue until 2002, said Troy Dere, principal investigator for the ATES project. "The goal is to complete the research and development necessary to prove a new way of training," he said in an interview.

"In the current way of training, we have no adequate means of training soldiers to use weapons when you can't see the opponent, meaning indirect fire weapons," said Dere. "The MILES program can only do direct-fire weapons. They have some methods by which they can artificially simulate but, in my opinion, simulate poorly, indirect fire weapons.

A laser beam is a direct-energy weapon. "If you can't see your opponent, it doesn't work very well," Dere said. With indirect fire, explosive rounds or over-the-horizon shooting, he added, "we need to he able to train soldiers how to use those weapons other than through live firings.

"So far, our modeling has been limited to laboratory exercises, simulations on computers," he said. "But we are getting very close to starring some hardware demonstrations."

The OICW weapon can be programmed to explode at a distance, "so you could program it to shoot into the window of a building, for instance, where you couldn't see your opponent but you could program the round to explode after it goes through the window," explained Dere. In an urban environment, "you have all sorts of problems," he added, such as reflection of radio signals. "Sometimes you can see your opponents, sometimes you can't. It's the toughest environment."

STRICOM is working with the developers of OICW on how the training equipment would be integrated with the weapon. "But we are a long way away from that," Dere noted. "The Marine Corps will be fielding OICW too, so they are interested in the trainer."

The ultra-wide band (UWB) technology is the foundation of ATES. "Something like the UWB approach holds the most promise to give us that type of training," said Dere.

The provider of the UWB communications and position-location links for ATES is Time Domain, based in Huntsville, Ala.

"Our technology is a completely different approach to doing radio and position location tracking," said Kevin Davis, head of Time Domain's government and defense group. "It is fundamentally different in that we use very short pulses of energy instead of a continuous wave," he said in an interview.

Frequency domain radios--typically used by military operators and in AM/FM broadcasts--are continuous wave. "We are not using a frequency or continuous wave system, but an ultra-wide band impulse communication," Davis said. That approach involves firing extremely short-duration pulses at a very high rate. Those pulses are spread over large amounts of bandwidth. The UWB underlies the spectrum currently used by frequency domain systems that are found in today's military and commercial radios.

The only way to simulate indirect fire accurately is to have precise location information so that a ballistic path of the round can be created in a computer simulation, explained Daniel E. Mullally, a research scientist at the University of Central Florida's Institute for Simulation and Training, in Orlando, Fla. The institute is working with STRICOM on the ATES program. Another partner in the program is Sparta Inc., based in Huntsville.

With ATES, Mullally said, "We pair up the location between the fire and the target and determine incapacitation, hit or kill." The UWB enables data transmissions between the target and the weapon that fired, and also helps to locate the players on the battlefield. "Since we are using time-modulated ultra-wide band, we have the capability to determine exactly where things are in space, by measuring the time of travel between the antennas erected around the training area and the individual or the weapon, or the sensor placed on the body of the soldier.

"We'll be able to data log the soldiers' exact positions and firings. In the after-action review, we will be able to provide a derailed critique."

Mullally acknowledged that this technology has yet to mature. "This is cutting-edge emerging technology. ... Accurate location is what we are trying to achieve."

Training Requirements

ATES is not only being designed for OICW training, but also to train future users of the objective crew-served weapon, a 25 mm system to replace the 50-caliber machine gun and the Mk 19 40 mm machine gun. The crew-served weapon will have a range of 2,000 meters, while the OICW range is about 1,000 meters. ATES also will support training requirements for the M203 grenade launcher and the 60 mm M224 lightweight mortar.

Time Domain's Davis explained that UWB offers much promise for communications and position-location systems used in complex battle zones such as urban areas. That is where "the traditional systems begin to fall short," he said.

He does not believe UWB signals would conflict with conventional radio signals because UWB operates at extremely low power, in what is known as the "noise level." The noise is the background, the signal is what is heard.

"When it comes to signal-to-noise ratio, we operate in the noise," Davis said. "The level of energy we transmit is as low as an appliance. ... We run low power in order to have high data rate, to share spectrum, and to operate in high multi-path environments."

UWB technology is "very high bandwidth, both in spectrum and in terms of data capacity," said Davis. "But we are not breaking the laws of physics." The extremely short pulses in the IJWB (each pulse is one 500 trillionth of a second long) have similar behavior characteristics as the systems in the 2 gigahertz frequency range, which are line-of-sight systems, he added. The pulses, because they are not continuous waveform, have more penetration capability through building materials. "We go straight through walls and floors, in a line-of-sight way," he said. "Those walls are transparent to our signal."

For civilian applications of IJWB, the focus is on wireless local area networks, Davis said. "We are nor trying to replace the cell phone." UWB could be used inside buildings, and then it would switch over to conventional cell phone architecture outdoors. Cells phones, he noted, often have difficulties in buildings and garages.

"Our technology is very robust in those areas where traditional technologies are challenged--where regular radios or any frequency domain radio have most difficulty being functional and reliable, our radio technology is particularly valuable because that is where it works the best."

Time Domain's brand of UWB is called "time modulation," or TM-UWB, which is sold as silicon-germanium chip sets called PulseOn. "We have it down to systems that are the size of a desk phone or slightly bigger," said Davis.

The systems for the ATES program use PulseON chip sets, which are small and can be made in large quantities at low prices, he said.

The TM-UWB component on the OIGW rifle will be antennas on the weapon so users can determine the azimuth, or the aim of the weapon. The company also is developing a calibration instrument. "The calibration and the simulation of the weapon would dovetail nicely with the position-location tracking communications capability that they will be examining for other applications, such as soldier communications and soldier tracking inside buildings."

One of the reasons STRICOM became interested in this technology two years ago, Davis said, was because scientists were having difficulties finding reliable means to track and communicate with soldiers inside buildings.

The Global Positioning Satellite (GPS) system generally is not available unless there is line-of-sight on three or more satellites, Davis explained. "You don't get line-of-sight when you have ceilings over you. GPS is a continuous wave, weak signal that has difficulty penetrating buildings. We are looking to complement or augment GPS."

Time Domain officials recently briefed the Joint Tactical Radio System program office, managed by the U.S. Army. That program aims to develop a common software-based radio that can support dozens of radio waveforms from all military services. "If that program is successful, it must be able to support new and emerging waveforms," Davis said. "There ought to be a way for us and for other emerging technologies to plug into that architecture using our chips, our antenna, to get access. Our architecture is a pure digital system, has all those things the JTRS program is targeted to accomplish."

Time modulation UWB is only one of possibly many other techniques for implementing this technology, Davis said. "In the future, there may be many different ways to do UWB as there are ways to do frequency domain radios."

The company is awaiting approval from the Federal Communications Commission (FCC) before it can commercialize UWB technology. For military experiments, however, no such approval is required, said Eileen A. Heaton, Time Domain spokeswoman. "We do not need an FCC rule-making to use UWB in the military."

UWB can operate in rain, smoke and fog, as well as with battlefield obscurants, Davis said.

One of the main challenges for this technology is interference mitigation, to prevent other radio users from blocking UWB signals. "Our architecture has to have an elegant way of withstanding interference from high-powered users in band," said Davis. "That is part of the trick--withstanding interference from other users."

Detection Device

Time Domain also is working on another STRICOM technology demonstration program called the lightweight personnel detection device (LPDD). The prime contractor in this project is the Boeing Company's military technology division, in Sr. Louis.

LPDD is an advanced instrumentation package for infantry troops that, if successful, will replace older versions of the MILES training system, said Gory Youmans, project director for instrumentation management at STRICOM.

LPDD is conceived as a replacement for the old MILES (called SAWE II), nor the new MILES 2000, which is non-instrumented, meaning it is nor equipped with GPS receivers or radio transmitters.

"Up until now, MILES 2000 was only used for home station training. In the future, it will go to the combat training centers," Youmans said in an interview. Because there is no plan to instrument the MILES 2000, the LPDD program will attempt to provide miniaturized GPS and radio systems for tactical training. "So if you wanted to adapt a MILES 2000 device in the future, or build systems like the LPDD, the technology will be there to support it."

There is a requirement for 24,000 instrumented MILES systems for the Army's three combat training centers at Fort Polk, La., at Fort Irwin, Calif. and the Combat Maneuver Training Center, in Germany, Youmans said. "The original intent was nor to have MILES 2000 at the training centers. But we found that it needs to go there. So I would expect that in the future, you will see that requirement modified to include instrumentation, position location radio and GPS.

The Army would like to replace all 6,080 SAWE II MILES systems fielded in the 1990s, Youmans said. They are heavy, at 14-16 pounds, and expensive to operate. They use bulky lithium batteries that weigh 2.2 pounds each and cost about $60 per soldier per day. "The systems are rarely used because they are not 'soldier friendly,"' said Youmans. The LPDD uses inexpensive AA alkaline batteries which operate the system For 2-3 days, depending on how and where it is used.

"At the training centers now, there is a lot of old MILES gear. MILES 2000 will replace that," he said. But the LPDD could supplement MILES 2000, which is not instrumented. "Depending on the program, you could incorporate the LPDD technology into a follow-on buy for MILES 2000, if you wanted to instrument and add a GPS receiver or a radio transceiver, so you could track soldiers on the battlefield.

"If you want to know what is happening in real time, track your soldiers all the time, you have to have a SAWE II MILES-equipped soldier or an LPDD-equipped soldier with a radio or GPS receiver," Youmans said. "With the MILES 2000, you would not know where your soldiers are at any given time, because there is no radio o GPS." The goal of the LPDD program, he added, is to demonstrate that the technology exists to produce a lightweight, low power device to replace the older, heavier systems now used to train soldiers at the Combat Training Centers.

Because of its weight, SAWE II MILES mostly is now used to track vehicles, where bulkiness is not as big an issue. But the Army wants to be able to track individual soldiers, which is the primary reason for pursuing the LPDD. The non-instrumented MILES 2000 gear weighs 4 pounds.

During the recent "joint contingency force advanced war-fighting exercise" at Fort Polk, the opposing force was given 30 LPDD prototypes, Youmans said. The goal was to test how well the systems could engage the blue force from the Army's 10th Mountain Division.

LPDD gear weighs 3 pounds. It consists of a vest with laser detectors, a helmet assembly that can be adapted as a hat, a laser transmitter at the end of the rifle and a box with a computer, a radio and a GPS receiver. Soldiers mount a MILES-compatible laser transmitter on their M16A2 or M4 rifle and "shoot" other similarly equipped soldiers. Each soldier wears laser detector arrays on his hat/helmet and torso that record where the soldier was "hit."

The system, unlike the MILES 2000, has a GPS receiver which records each soldier's position on the battlefield throughout the training exercise. It also has a radio, which sends information about each force-on-force engagement back to a central station for real-time display and after-action review.

STRICOM awarded a contract to the Boeing Company in September 1999, to build 30 prototype devices to demonstrate the LPDD technology. Boeing's team includes Inter-Coastal Electronics (Mesa, Ariz.), Oerlikon Contraves AG (Zurich, Switzerland), Time Domain and DRS Optronics (Melbourne, Fla.). The 30 systems were delivered in June, said Joe Russek, LPDD program manager at Boeing.

The current systems only use GPS and radio frequency technologies, said Russek in an interview. "But UWB is being looked at." That technology is not integrated into the program yet, because it has not fully matured, said Russek. "UWB is in the forefront and has a lot of potential, but it is not yet mature enough to be used in LPDD."

The LPDD program, said Youmans, is working with the ATES project in evaluating UWB, "to see if the technology can replace the GPS and radios we now use." The current GPS technology provides accuracy to a couple of meters. "If UWB proves out, it will give us centimeters' accuracy. That gives us a big edge when we try to train indirect fire weapons, because you need to know precisely where the target is, so you can predict where the round will land."

STRICOM also plans to adapt the LPDD system to meet Marine Corps requirements. "We are going to provide them with 12 prototypes by January 2001," said Youmans. "They will assess how well this system works in the urban warfare training requirements.

"The low weight, low power nature of this technology means that we can provide the infantry soldier with a highly realistic, highly functional training device that doesn't interfere with his tactical equipment.

"Our only challenge is coming up with the money to build the new systems for our three Combat Training Centers," Youmans said. "We have a requirement to buy 24,000 systems, but current fiscal constraints have pushed the fielding date out at least four to five years."

STRICOM ultimately wants to integrate tactical engagement simulation into all new tactical weapon platforms. "We've made huge technology advances in miniaturization and power conservation. ... Now the challenge is to get the technologies to the troops."

The MILES prime contractor, Cubic Defense Systems, meanwhile, has developed a ground instrumentation system, where each of the players has a GPS and a radio link connected to a central site. "We are able to use that radio link in the instrumentation system to model the non-line-of-sight weapons," said Seth Bokmeyer, director of business development at Cubic, in San Diego. "We are looking at different concepts and haven't decided which we would propose," he said in an interview. "MILES would be part of it. There will be a need for instrumentation to augment MILES."

The company has delivered 9,000 soldier-wearable systems and 300 vehicle-mounted systems. Last February, Cubic was awarded a $24 million contract to provide MILES 2000 equipment. STRICOM so far has placed $134 million worth of orders.

'Embedded' Trainers Planned for Army's Next-Gen Combat Vehicle

In future military deployments, combat vehicle crews will have access to sophisticated training aids, regardless of their location, U.S. Army officials predict. Those training tools would be built into the combat vehicles, making it possible for soldiers to hone various war-fighting skills in their spare time.

The U.S. Army plans to install these so-called "embedded" trainers in its next-generation combat vehicle, known as the future combat system (FCS). The FCS is in the early stages of design, under a program managed by the Army and the Defense Advanced Research Projects Agency (DARPA). Four industry teams are competing for a contract award in 2003.

FCS operators will be able to fight virtual battles in computer-generated scenarios, or will have the capability to conduct live-fire drills against three-dimensional virtual targets, said Michael Macedonia, program director at the U.S. Army Simulation, Training and Instrumentation Command (STRICOM), in Orlando, Fla.

"We are an Army that is losing training space," Macedonia told an industry conference, sponsored by the Association of the U.S. Army. Less access to ranges means more simulator-based training, he noted. In the context of the FCS program, particularly, preparing soldiers for that vehicle will be more demanding than the training that Ml Abrams tank and Bradley infantry vehicle crews typically undergo, he said. The FCS will have "exotic gear" and much more complicated command and control systems, Macedonia added. "Imagine the kinds of soldiers you'll have in FCS. ... The weapons are complex, the ammo is very expensive. Missions will be complex."

To field successful training tools, the Army will have to "figure out how to simulate the city, for example, in a contingency operation," he said. That means having digital models that represent actual cities where soldiers would be expected to fight. "We have to start thinking how we'll employ [the simulations] in a joint task force and how we train for the mission."

The complexity of the FCS platform will be compounded by the use of unmanned vehicles as part of the standard formations, and the sophisticated digital networks that will link every vehicle and weapon system in the battle zone.

The training devices developed for FCS crews will have to address a number of issues, said Macedonia. "How do soldiers interact with robotic systems? ... How do sensors interact with shooters?" Additionally, he said, "We have to recognize that our enemies will have similar equipment."

The Army has attempted to develop embedded trainers for about 20 years and has not been successful. "There has been a requirement for all Army systems [to have embedded trainers] since the late 1980s," Macedonia said. "We haven't done it very well for a variety of technological and cost issues."

FCS mandates the use of embedded training, but at a more advanced level than previously envisioned for other weapon systems, he explained. "It doesn't just mean you pop up a manual on the screen to explain the assembly or disassembly of a gun." It means being able to perform "virtual gunnery," for example, or learning how to integrate FCS platforms into the instrumentation at the National Training Center ranges.

STRICOM developed a prototype Ml tank turret trainer with embedded gunnery, Macedonia said. "But we still haven't resolved the technical issues." Soldiers in the field, meanwhile, are waiting for advanced training equipment to become available. "Every time they go to a mission, they call STRICOM and ask for training equipment to polish skills and prepare people before they go into battle," he said. "The solution is embedded training, so when they deploy, they can prepare virtually [and] get their heads into the problem of that fight."

One problem that has emerged in Army training is the lack of ranges or simulators that support specific weapons. The upshot is that, when the Army conducts a major exercise at the National Training Center (NTC), the commanders will choose to not use those weapons because the shots cannot be registered by the NTC range instruments. "There are weapons that commanders don't take to the NTC because they don't count," said Macedonia. "They can't be represented, can't use it with MILES." MILES is a laser-based direct-fire training system. One example is the Mk 19 grenade launcher, Macedonia said. "We don't have ranges or simulators to support it. Can't take it to the NTC and get credit for kills. So nobody trains with it. I hope FCS won't be that kind of system."