American troops love their GPS. So much so that many troops (in all the services) buy their own. GPS receivers issued by the military tend to be older technology, which means they are larger, heavier and have fewer features. For example, soldiers or marines, who spend a lot of time carrying their equipment on their backs, prefer to spend a few hundred dollars on a full-featured, half pound commercial GPS, rather than lugging around the two pound military issue GPS receiver. The military is trying to keep up with the rapid improvements from the commercial GPS receiver industry, but it is difficult because the military contracting system (with a few exceptions, like the Special Operations Command), is not built for speed. So the brass look the other way as the troops go to battle with GPS gear they have bought themselves.