Global Positioning System
Soldiers looking at a GPS unit

A Cambodian military commander (L) shows his men how to use a GPS before fighting broke out with Thai soldiers on Oct. 15, 2008.

Tang Chin Sothy/AFP/­Getty Images

­GPS turned the world into a giant, instantly accessible map.

The U.S. Department of Defense built the U.S. version of GPS, Navstar GPS, between 1989 and 1994 [source: Britannica]. It launched 24 main satellites that constantly emit radio waves. Anyone with a receiver that can pick up a few satellites' waves can triangulate his or her position.

GPS became an excellent tool for navigation. A soldier with a receiver could now navigate in the pitch dark or in any foreign place without a map.

The navigation tool also proved helpful for planning strikes. If a soldier who is carrying a GPS receiver meets enemy troops, he or she can record the enemy's position -- down to the longitude, latitude and altitude. By sending those GPS coordinates to fellow soldiers, the individual can alert the commander, the attack plane and 500 other soldiers as to the enemy's location. Being able to immediately blow the enemy's cover changed war.

The Gulf War illustrated the change, says Roland. "Americans feared the Iraqis would have an advantage because they'd be fighting in the desert in their own country. But it turns out the Americans had the advantage because they had GPS receivers. They could navigate at night and in dust storms. They always knew exactly where they were and where the Iraqis were."

GPS has also made air strikes more accurate. Satellites are used to map the targets and guide the bombs and missiles. These strikes minimize collateral damage and civilian casualties [source: Roland]. As time goes on, we are discovering more applications and depending more on GPS.

Ultimately, though, the outcome of war depends on more than just advanced technology, but it certainly doesn't hurt your chances on the battlefield.

That ends our tour of military technologies that changed the game, for better or worse.