If you have watched the History Channel or the Military Channel and seen footage of naval anti-aircraft fire during World War II, you realize just how difficult the problem of tracking an outgoing bullet just might be.

Once upon a time, my friends and I got to work on something pretty cool. I never thought at the time I would be writing about it years later. If you look up my resume, you will find I spent more than a couple of years at Cal Poly Pomona. When I would drive down the freeway, I would look off to the side and see what was the General Dynamics Pomona facility, and I thought that it would be a fun place to work someday. I did eventually get to work there.

On its back lot, there used to be this droid-looking thing. Inside was a radar, whose sole job was to track outgoing bullets fired from a .22 caliber rifle. Now one might have asked at the time: What good is it to track an outgoing bullet? But the minds behind that had a plan. If you have watched the History Channel or the Military Channel and seen footage of naval anti-aircraft fire during World War II, you realize just how difficult that problem might be. It is amazing those people shot down as much as they did.

If radar could track an incoming hostile threat and an outgoing bullet and a computer could make the two intersect at a point in space, that would be a good way to shoot down stuff much more reliably. Of course, naysayers said that outgoing bullets could not be tracked: They were too small, too fast. These people just kept playing with that .22 caliber rifle until they could reliably track the bullet on the radar.

Enhanced computing systems

Then the real work started. Go get a 20 mm Vulcan Cannon from General Electric and add either depleted uranium or tungsten ammo. Add a much more powerful radar system, split into a search subsystem and a tracking subsystem. Combine those with an electromechanical marvel big enough to slew the entire 6-ton beast really fast. Add what at the time constituted a few 8-bit MCUs and a lot of discrete logic in a bit-slice machine for radar signal processing and motion control. What you have is the beginnings of the MK 15 Phalanx Close-In Weapons System. It has been through a myriad of upgrades such as a Forward-Looking Infrared (FLIR) sensor and much better computing systems since I last worked on one, but the principles are the same.

The talk was that the future of Phalanx was limited: Phalanx was too good of a weapon. Once the U.S. Navy outfitted every ship and maybe sold a few to foreign navies that would be it. The creative minds have stretched the thing to take on not only fast-moving air targets, but also slow-moving ones, small surface targets, and more. But the number to be built was pretty limited. Well, at least that was the case until one day in May 2004 when someone I do not know was sitting somewhere near Baghdad, listening to mortar rounds fall near them, probably followed by a phone call or two. If the military could spot stuff coming toward a ship in a seascape, couldn't they spot stuff falling from high in the sky down into an urban environment? Might take some software changes, but falling mortars are pretty easy to track.

U.S. Army’s Centurion

After a quick change, the U.S. Navy’s Phalanx became the U.S. Army’s Centurion Counter, Rocket, Artillery, and Mortar (C-RAM) as shown in Figure 1. Mounted to a flatbed truck with a generator and outfitted with self-destruct rounds that explode on contact with a target or tracer burnout, whichever comes first, the concepts are the same.

Figure 1: The U.S. Army’s Centurion C-RAM

According to the folks at Raytheon, so far at least 105 attacks on the Green Zone near Baghdad have been thwarted by C-RAMs. Rumor has it some are enroute to Afghanistan.

The lessons:

1. Never give up on a concept because it looks hard. What takes "unobtainium" now has a way of becoming reality 20 years later. Unless you are violating a law of physics or a commandment, keep trying.

2. The same law applied to the embedded electronics life cycle can add new capabilities to what was thought of as an excellent platform just a few years earlier. Keep trying.

3. A solution that works simply, elegantly, is a solution, and it might solve more than just the problem that inspired it. Keep trying.

4. For every measure, there is a countermeasure. There is only one way to assure safety, and that is to stay ahead. Keep trying.

For another proof-point on lesson #3, go look at the Lightweight Counter-Mortar Radar (LCMR) at www.srctecinc.com and see what I mean.

To all the folks out there risking their lives for our safety, and the folks back home coming up with ways to keep them and us safe, thanks for your living the “keep trying” part.

P.S.: This is my last commentary installment for the Military Embedded Systems team for a while, but I am still around working on all kinds of stuff. Tweet me at @dondingee.

To learn more, e-mail Don at [email protected].