The top of the line. (computer simulation at Link Simulations)

The most sophisticated computer simulations today are done by commercial corporations like Link Simulations Systems Division of the Singer Company (yes, the same people who make the sewing machines). At their Silver Spring, MD, location they develop simulators for private corporations and for the U.S. government as well.

The U.S. Army hired Link to create a battlefield simulator called ARTBASS which would leave most computer game enthusiasts astonished with its capabilities. ARTBASS is a battalion level simulator for use in training battalion commanders in maneuver, fire support, and logistics. It offers a computer controlled scenario providing real time and interactive simulation of tactical operations. ARTBASS is definitely not a microcomputer simulation--it requires a multi-tasking processor of about the power of three Vax 11/780 minicomputers.

While the simulator is capable of running without graphics, it is the graphics that make ARTBASS so useful. The actual system is set up as five training stations (two maneuver control stations, one fire support station, one administration and logistics station, and one threat station) each of which includes CRT color displays. The screens depict in either two-dimensional or three-dimensional format the view of a potential battlefield from any map location. People training on the simulator, however, do not sit in front of the screens but are battalion commanders actually in the field in their command posts.

The company commanders see the screens and are in radio contact with the battalion commanders (just as in a real battle situation). The "combat math model" which drives the simulation can plot and move up to 200 separate units of 19 different types on 5000 square meters of terrain. Movement is in real time with updates every minute for land units and every 15 seconds for aircraft. The company commander may change his viewing position, and all will appear as if he were actually on location.

The "combat math model" calculates line-of-sight between all units, monitors visual detection adjusting for day/night and terrain features, and simulates fire as units detect one another. Air missions, degraded movement due to "hits" and casualties are all calculated in real time. The software is written in Fortran with only a few graphics routines in microcode for display speed. The scenario we viewed on a visit to Link was a Central Europe mock-up, and it was like looking through a picture window. While the units themselves were represented by "counters" and looked unreal, the terrain was very realistic, showing contours and lighting effects for different times of the day and night.

Link uses all off-the-shelf equipment to build the training stations. The entire training system (the army has purchased ten) is loaded onto two semi-trailer trucks--one truck for the generators and processors and the other for storage of the actual workstations. The workstations are unloaded at the training site and connected by cable to the processor, which remains on its carrier.

Power Generation Systems

An older line of business for Link is power plant simulation; Link has been building simulators for the power industry since 1968. Both nuclear and fossil fuel plants have been replicated. The power plant simulators are typically mock-ups of the control rooms of these plants, complete with exact reproductions of the equipment used in the real control room--even the walls are painted with identical color schemes; plant noises and lighting effects are also reproduced in the simulators. As one Link engineer put it: "We are in the business of fooling people into believing they are where they are not."

The heart of these power plant simulators is again a minicomputer which remains behind the scenes running a mathematical model of everything in the plant from the reactor core (the most difficult part of any plant to simulate) to the large generators most plants contain. Since these replicas operate in real time, the realism is almost perfect (even boredom in watching for certain occurrences is present).

An instructor station, which looks like another computer terminal, allows the instructor to simulate virtually any plant condition: power demand, malfunctions, routine changes, and so on. A complete "history" of the happenings during any training session can be kept for review after the fact. Trainees can also retry circumstances with which they have had difficulty in previous sessions.

While the power plant simulators are built exclusively for training, there have been instances where the design of a plant has been changed because the simulator pointed out circumstances that the actual plant did not handle well. Innovative information displays used in some simulators are now being incorporated into actual control room panels.

Link Simulations Systems Division, 11800 Tech Rd., Silver Spring, MD 20904, (301) 622-4400.