YOU ARE HERE
May 21, 1998
First used by the military to locate troops and tanks, the Global Positioning System is now being used in a wide range of civilian uses. Spencer Michels looks at this how this network of satellites is changing how we get from point A to point B.
SPENCER MICHELS: This new BMW, sticker price $72,000, comes equipped with a $2500 built-in navigation system right out of the electronic battlefield. David Hall of Trimble Navigation is piloting the car.
A RealAudio version of this segment is available.
May 20, 1998:
Pagers, radio and television relays are disrupted due to a satellite mishap.
April 4, 1997:
The debate over the F-22 air superiority fighter .
September 11, 1996:
Privatizing the Presidio, San Francisco's historic military post.
Browse the NewsHour's coverage of science and technology issues and military affairs.
Trimble Corporation - makers of civilian and military GPS units.
DAVID HALL, Trimble Navigation: Let's take a look for a restaurant. So we've got a restaurant that's nearby, and so it tells us we're 1.6 miles from that location. And that tells us by the arrow where we are. It just told us to turn left ahead.
SPENCER MICHELS: What's guiding us through the suburban streets of Silicon Valley is an array of satellites called GPS, or Global Positioning System. The satellites send signals to receivers in our car which are used to calculate our precise position.
SPENCER MICHELS: What if there's like a one-way street? How's this thing going to know that?
DAVID HALL: There's a digitized map that's CD-ROM-based that has all that information in the system. It's quite accurate.
SPENCER MICHELS: The GPS system is widely used on a variety of cars in Japan and on many rental cars in the U.S.. Portable units are now being sold for use on any make car and can be linked to laptop computers.
COMPUTER VOICE: Six hundred feet, turn left.
DAVID HALL: We turn left, and we have arrived.
COMPUTER VOICE: You have arrived.
DAVID HALL: And, by golly, there's the Tao Tao Restaurant.
SPENCER MICHELS: Looks closed. How come it didn't tell us that?
A military system is now changing civilian life.
SPENCER MICHELS: Having GPS on vehicles is useful for more than just finding a restaurant. Fire trucks, police cars, and ambulances are starting to use them in a number of U.S. cities. The San Jose based non-profit "Outreach" program depends on GPS linked to computers to keep track of its fleet of 160 vans carrying disabled people to 2.000 appointments a day. Kathryn Heatley is the CEO.
KATHRYN HEATLEY: In order to make real time changes, you have to know who's on board, and to accommodate their various disabilities. And you can't have drivers with a map and a pencil and a vehicle, and you don't have a great deal of radio time. So what we have is a very efficient system built on electronics where my main office and my dispatchers are linked to the vehicle and to remote sites, and we can do all of those rides around the clock very efficiently.
SPENCER MICHELS: The same sophisticated GPS techniques used on California streets are also being promoted for use by boaters and fishermen navigating unfamiliar waters, and by hikers on remote trails. The technology was originally intended for the military. In fact it's vital for U.S. forces planning for potential military action against Iraq. GPS is used to guide the new generation of Cruise missiles to targets gets on the ground, as well as to tell airplanes and ships exactly where they are.
A 24-satellite constellation.
Here's how it works: 24 satellites--launched and maintained by the military--are in continuous orbit 12,000 miles above the earth. They send down signals, and --because of atomic clocks on board. They keep extremely accurate time. Using geometry, the satellite signals can pinpoint exactly where the individual or missile or aircraft is, and how to get the weapon to the target. Stanford Professor Bradford Parkinson, a retired Air Force officer, is considered the "father" of GPS.
BRADFORD PARKINSON: It's particularly useful in cases of limited war where you don't want to damage things that you're not really shooting at. And so GPS is actually a surgical strike weapon, which minimizes collateral damage.
SPENCER MICHELS: GPS has been increasingly used on aircraft, like the F-16 fighter, although not all military planes are equipped with the system yet. In addition, individual soldiers issued hand held, battery operated GPS units called pluggers.
BRADFORD PARKINSON: The principal application was in ensuring that everyone in a battlefield area was dealing from the same map. And it turns out that in Vietnam and other places, we had experiences where people did not know where they were relative to other organizations and it turned out that was disastrous.
A double-edged sword for the military?
SPENCER MICHELS: U.S. Air Force pilot Scott O'Grady, honored here by President Clinton, provided the most dramatic use of GPS. He was rescued by American forces, after he was shot down by a Bosnian Serb missile over Bosnia in 1995. He used a hand held unit to find his exact position and radio it to rescuers before he could be captured by hostile forces. The device O'Grady had with him was made in California's Silicon Valley by Trimble, the firm founded and headed by Charlie Trimble. The company makes a whole line of military and civilian GPS units.
CHARLES TRIMBLE: GPS is becoming much smaller; it's being integrated with communications, and so basically you're going to find GPS receivers in all of the mobile platforms in the military.
SPENCER MICHELS: What the military doesn't want is for an enemy to use the American-made GPS system against this country.
CHARLES TRIMBLE: Any time you have this sort of dual use, the military does have the challenge of how to deny civilian access to it in a theater of operations. You know, try as you may, the enemy is always going to be able to use some of what you have against you.
SPENCER MICHELS: To protect its highly accurate system from being used by an enemy, the military for years has sent a slightly distorted GPS signal from its satellites, a signal that was judged precise enough for civilians. But civilian users, wanting more and more accuracy, figured out how to correct for the distortion.
Recently, the government decided it would change policy and send out an accurate signal for everyone. Though military uses are seen as essential, it is in the civilian market where GPS probably will gets its most use. In fact, 95 percent of sales are in the commercial area. Three million devices have been sold, and 250,000 more get bought each month. Prices have dropped to as little as $100 and $375 for devices linked to digital maps. While GPS units can help hikers, they can also aid civilian aircraft.
Using GPS to make the airways safer.
KGO-TV ANCHOR, 1983: The best information we have this evening is that Russian pilots blasted that airliner out of the sky, killing all of the passengers, including several Americans.
SPENCER MICHELS: In 1983, Korean Airline Flight 007 went off course over Russia, and was shot out of the sky by the Russians. An investigation revealed pilots had set their starting point wrong, and the error was magnified as they flew. GPS could have kept the plane on course. To avoid such disasters, and to provide safer landings, the Federal Aviation Administration asked Stanford to test an airborne GPS system. Researchers equipped a United Airlines 737 with GPS receivers, fed the navigation information into the plane's auto pilot, and added a new sensor. Clark Cohen headed up the team.
CLARK COHEN: We pulled out a row of seats, installed a rack with our equipment on it, plugged into their autopilot, and within a few days we were performing complete automatic landings, hands off, up to a total of 110 times.
SPENCER MICHELS: During one landing, the satellite signals were interrupted momentarily, and the pilot--alerted to the condition--took over.
CLARK COHEN: I don't think there will ever be a time when the pilot is not needed in an aircraft.
GPS in the field.
SPENCER MICHELS: Some airlines are already using GPS routinely for navigation on over-water flights, and, United Airlines officials say, GPS will be the key in redesigning the nation's air traffic control system to permit greater flexibility and efficiency. Besides airborne experiments, Stanford researchers are developing GPS for use by farmers bent on increasing accuracy of their plowing and in decreasing labor costs. Prof. Parkinson and his students have outfitted this tractor with an array of GPS receivers, linked to a computer. They took their experimental vehicle to a farm south of Fresno to see what it could do. They ran the tractor in the fog, when visibility was bad. They ran it at night; they ran it with a driver, and then without one. Michael O'Conner oversaw the program.
MICHAEL O'CONNER: I was very excited. The first time it worked, I couldn't believe it. And just watching this thing drive where I was asking it to go, and it was amazing. It was very accurate. It could repeat the same tire tracks time and time again. It was just wonderful.
SPENCER MICHELS: To show how accurately GPS could guide the tractor, they plowed a block S, for Stanford, in the field, something a farmer probably could never do. Mark Borba, who lent his field to the students, was impressed.
MARK BORBA: We're blessed with a university and a research-based system here that delivers technology to us, and the more quickly we can employ it, the better advantage we will have over our competitors.
SPENCER MICHELS: The experiment continues with the prospects high for commercial use within a few years.
BRADFORD PARKINSON: I would say it's going to be in every automobile. It's going to be in probably half the farm tractors. All the mining equipment is going to be, open pit mines will be operated robotically. I see it in ships. I see it controlling all the timing in the whole nation. I suspect that within the United States alone there'll be over 20 million users.
SPENCER MICHELS: As Global Positioning System devices become more widespread, and factories crank out newer and less costly models, users want to ensure that the signals they now get for free won't cost them. And the makers and designers of GPS equipment want the military to continue the expensive business of maintaining the satellites and adding to their number to ensure robust and accurate signals.