In 1982 Charlie Trimble, a Silicon Valley entrepreneur, paid Hewlett-Packard $80,000 for the remains of a canceled engineering project-shelves full of research notes, and the result of that research: a circuit board the size of a coffee table. The circuit board could pick up a signal from the first satellite in what would eventually become the Navstar Global Positioning System (GPS), a ring of 24 military satellites orbiting 18,000 kilometers above the earth.

Trimble’s company, Trimble Navigation Ltd., has since shipped GPS receivers for applications as varied as tracking wild goats in Galapagos and measuring tectonic movements atop Mount Everest. In 1991, Trimble sent $7 million worth of receivers to Gulf War GIs. Trimble’s principal competitors began their careers working for him before founding their own companies. And after nearly two decades of evangelizing, Trimble still hasn’t lost his enthusiasm for the technology-there’s not a trace of doubt in his voice when he lauds GPS for doing everything from ending world hunger to winning the Cold War. “Knowledge of position has tremendous benefits-to feed the world, to provide more efficient commerce and therefore better quality of life, to provide better safety and security,” he says.

On the other side of the country from Charlie Trimble’s office, in Lowell, Mass., Charley Richardson, director of the Labor Extension Program at the University of Massachusetts, has spent just about as many years studying the effects of technology on the workplace as Trimble has developing and selling GPS receivers. Richardson recently completed a study on the effects of GPS-enabled monitoring in the transportation industry. He believes GPS can lead to gross violations of an individual’s right to privacy, a problem that he believes far overshadows the technology’s potential for good.

Between these two extremes lie the rest of us, most of whom haven’t really thought all that much about GPS. This is, after all, a technology that has been touted for the past 20 years as being on the verge of changing the world, but which somehow never quite meets the expectations of shareholders, pundits or the press.

The idea is simple: when a GPS receiver picks up satellite signals, it calculates its position based on its distance from each satellite. A receiver needs three satellites to get a fix on its latitude and longitude; to give an extra measure of reliability, and to determine altitude as well, the unit needs to fold in a reading from a fourth satellite. A constellation of 24 satellites gives round-the-clock, global coverage.

Creating this system was an elegant feat of engineering, but the public has managed to restrain itself from buying in. In 1991, after the Gulf War victory, commercial applications like in-car navigation were expected to rocket to an $8 billion annual U.S. market; instead, people bought road maps. The domestic GPS market finally inched over $1 billion in 1997, according to Mountain View, Calif.-based market research firm Frost & Sullivan. Last August, Trimble was removed as CEO of the company he founded by his board of directors, after several quarters of disappointing sales. When it comes to the effect GPS will have on our lives, both Trimble and Richardson are speaking in the future tense.

The history of GPS is a classic case of technology in search of a market; the future of GPS will have less to do with technology than it does with politics, with economics and with simple human nature.