Combining Digital with Physical
DYNAMIC SAND TABLES DISPLAY PHYSICAL TERRAIN FROM DIGITAL DATA.
Advances in three-dimensional graphics and related technology provide warfighters with vivid terrain maps on their computer screens, but it isn’t always easy for war planners to gather around a computer screen and talk about what they are seeing. It may sound old-fashioned, but sometimes the best way to plan a battle is to stand around a battlefield map and talk about it.
And so typically when Army brass would like to do this, they order the creation of a physical model, or a sand table, that accurately depicts the terrain in question, explained Douglas Caldwell, a physical scientist at the Topographic Engineering Center (TEC) of the U.S. Army Engineer Research and Development Center.
“Armies have been involved with sand tables since ancient Greece,” Caldwell told Military Geospatial Technology. “Basically, the development of a physical model, one you can see and touch, has been used in briefings here for a very long time. It’s something that people can readily identify with. Some people have difficulty reading maps, so a physical model is something that they can identify with immediately and understand.”
The surface of a traditional physical model mirrors the hills and valleys and rivers and roads of the battlespace in question. Such a model provides a quick and easy visualization of the lay of the land, enabling many soldiers at once to see clearly the topography of the area.
But building such a physical model can take several weeks, and then once built, it must be transported and stored. Such a model, carved from plastic or some other substance, may depict a location where a battle might never occur. All of these factors cost the Department of Defense time and money.
“Once a physical model is built, it takes up space, it weighs something and you can’t easily change the area that is shown. So when you build a traditional static physical model, it’s a onetime operation. You construct something and you have a static physical device. Then you have to store them and transport them. There are other kinds of issues associated with them,” Caldwell said.
Meanwhile, warfighters could use digital maps on their computers quickly and easily and e-mail files to one another, but they couldn’t gather and discuss them quite as easily as they could physical models. Army scientists began to examine the concept of combining the best features of both technologies to create a dynamic sand table—one that could change on-demand. Caldwell noted that the first X-Men movie really excited the imaginations of Army engineers, as the band of mutant superheroes used a reconfigurable table to study a schematic of New York City in a way similar to what a dynamic sand table might do.
So more than three years ago, the Army TEC released a solicitation through its Small Business Innovative Research (SBIR) program to invite companies to attempt the creation of a dynamic sand table.
“We thought it would be a great idea to combine the advantages of the physical model, which is that people readily understand them and can easily get terrain concepts from them, but with digital data,” Caldwell said. “The advantage of digital data is that you can move anywhere at anytime and reconfigure and redisplay your information. So this concept is a cross between a physical model and a digital system.”
The dynamic sand table that came out of the SBIR initiative uses digital geospatial data to drive 7,000 pins across a table. The digital data determines the height of each pin, forming peaks and depressions as required to accurately capture the terrain being studied.
“It’s like the bed of nails toy where you put your hand underneath and press up and it shows an image of your hand,” Caldwell noted. “This is essentially a digital version of that, but instead the nails are controlled by your elevation data.”
The dynamic sand table also has a latex surface spread over top of the pins. A vacuum pump holds the latex fast to the pins, but it is flexible enough to rise and fall with the height to which each pin adjusts. The latex also serves as a projection screen, enabling warfighters to show maps or imagery or anything else associated with the terrain on top through an overhead projector.
Warfighters can then quickly configure the table to depict a different area.
“When you want to move to a different area or a different scale, you drop the pins and you can put in a new set of data and a new set of images and then you can move to a different area,” Caldwell said. “So what we really have here is a physical model where you can actually see the terrain and feel the bumps and valleys and mountaintops and things like that. But it is reconfigurable. As soon as we are done looking at one set of images, we can reset the system and pick up a new area and new maps and new images and move to that.”
U.S. military forces can save a significant amount of time and money through the use of dynamic sand tables because they don’t have to be stored and maintained like traditional physical models. Instead, the sand tables remain in use, being reconfigured as required to depict different terrains.
To date, the company that manufactured the table—Xenotran Corp., based in Glen Burnie, Md.—has sold only one of the tables, and that to the U.S. Navy.
“They’ve done a wonderful job on it,” Caldwell remarked.
SBIR RESULTS
Dr. Derrick Page, founder of Xenotran, told MGT that his company sold the first table to the Navy last year and installed it in Mississippi right before Hurricane Katrina hit the area. Page reports that the table survived the hurricane unscathed and has been working well for the Navy.
“In addition to selling it to them, we do have a maintenance contract,” Page said. “We have sent engineers down there about once every month. This being the first one out of the box, we wanted to make sure that we could catch any problems. It has been pretty good down there on the whole. A few little problems, but that was to be expected.”
With the Navy purchase, the dynamic sand table still technically falls under the auspices of the SBIR program. Xenotran successfully completed the first phase of the program after three or four initial months of work by developing a prototype table. The company then went through Phase II of the program to develop the fully operational table. Now, Xenotran is in a Phase II Plus portion of the SBIR program.
“The first phase, depending on which department or military branch you are working with, involves an award on the order of $100,000,” Page explained. “Then once you have shown good progress under Phase I and you have a chance to design a program for Phase II, you can submit an application to move into Phase II. That is frequently about a million dollars, plus or minus.
“Interestingly, Congress realized that a lot of companies out there were making a living off of these SBIR programs and wanted to do something about it to make them commercial,” Page added. “So there is an incentive program now called the Phase II Plus.”
The incentive program permits the SBIR sponsor to match each dollar of sales during the Phase II Plus phase up to $500,000 overall. The idea is to encourage companies to commercialize their products instead of waiting for the military to buy them or invest more money in the concept.
Page is optimistic about future sales of the dynamic sand table, although he predicts the military will become its first big customers.
“The problem that we run into is the long procurement cycles of military equipment. It’s a stretched out procurement process. It has to be budgeted for the next year and then approved. So it’s a fairly long time, two years or more, before you can actually sell to a particular customer,” Page noted.
So while the U.S. Army sponsored the SBIR program, it has not yet purchased dynamic sand tables for its own use. But meanwhile the commercial marketplace is driving Xenotran to bring the costs of an individual dynamic sand table down, another factor that would benefit the U.S. military. Sales of the dynamic sand table would really pick up if the price could come down to the point of a high-end plasma television, Page estimated, although getting there will take some work.
HOW IT WORKS
Page once worked as an engineer on X-Y addressing for laptop computer screens for Japanese manufacturer Lexi Corp. Essentially, his work dealt with the identification of a single pixel on a screen through its position along an X-axis and a Y-axis.
“This was using an electrical method,” Page said. “We realized that if you wanted to have mechanical pixels then you would want to have something different. It would be too expensive to drive each bearing with some kind of an electric motor, up and down. There are 7,000 of these pins as it were on the sand table itself.”
And so Xenotran combined the X-Y addressing concept with pneumatic controls instead of electric controls and patented its method of doing so.
Each of the 7,000 pins has a corresponding hole in the table, and each hole has a small bladder along both X- and Y-axes, Page said.
“If we were to blow up the X and the Y bladder, then that pin would be locked into place. If we want to release the pin and let it drop, then we would have to release the pressure both in the X and the Y,” he explained. ‘If we want to lock it, we could lock it with either the X or the Y. You have to have two brakes on each one, one controlled by the X and one controlled by the Y array. Then each pin can be locked or unlocked at will.”
All of the pins start at the lowest elevation, and then the system locks and lifts them about a quarter of an inch. Depending on the digital instructions fed to the table, it will release some of the pins, which will fall under the force of gravity. Some pins remain locked. The process is repeated about 20 times, Page said.
“So when you are finished with raising the whole array and dropping selective ones, the mountaintop pins would have never been dropped,” he added. “The ones forming the valley at the lowest level would be dropped every time. The ones that are halfway up the hills and valleys would be dropped some of the time.”
After several minutes, the dynamic sand table has replicated the target terrain from a digital map.
Once the model is complete, the pins and their latex screen can be used for lectures, demonstrations and other purposes. The process also allows more than one sand table to use the same data at the same time.
“So if you wanted, for instance, to have somebody in the Pentagon and somebody in Afghanistan, you could have two sand tables and they could be both observing the same terrain,” Page said. “We are not limited to one site as we would be with the old-fashioned way of doing it with a hand-carved model. You can have multiple displays in different geographic locations all depicting the same thing.”
COMPLEMENTARY TECHNOLOGIES
Joseph Tesar, director of research and development at Cybernet Systems Corp., believes the dynamic sand table is an excellent example of the incremental application of technology.
“Currently, the military makes a physical topographic model and uses it to gain a better understanding of the topology. Multiple personnel will stand around the table discussing items on the model and their relationship to each other,” he said. “Using interpersonal communications is still a very viable way to communicate effectively, especially when you are trying to develop a common strategy. A dynamic sand table builds on this successful communications concept by making the physical model more readily reconfigurable.”
Cybernet Systems of Ann Arbor, Mich., competed in the first phase of the dynamic sand table SBIR. Although the Army TEC selected Xenotran to move into the next phases, Cybernet Systems is currently in Phase II Plus with a method of viewing digital terrain maps on handheld computers.
“TEC has provided significant development support for advanced methods for visualization of terrain maps. We received Phase I, a Phase II, and we are now into a Phase II Plus to develop pseudo-3-D methods for viewing topographic maps on a mobile PC,” Tesar said.
TEC’s Caldwell cautioned that neither digital terrain maps nor dynamic sand tables are intended to be an independent solution.
“We would always say that we find the two technologies complementary. We don’t think the sand table would replace computer graphics,” he said. “Typically, once the sand table is configured, anyone can stand around and work with it. You don’t have to know anything about 3-D graphics to actually operate it. It’s a little bit simpler, but there are things that you can get out of 3-D visualizations that you can’t get out of a sand table, so they will always be complementary technologies.” ♦
