Satellite Network Goes From Cold War to Cold Cash Ventures : The $10-billion military system spawns money-saving plans for airliners and street-finding gear for car makers. But security needs are bumping up against commercial desires.
Last summer, participants in an around-the-world air race flew across the former Soviet Union, providing a dramatic illustration of the newfound freedom of the skies in a region where foreign planes were once shot down.
But the pioneering course they charted reflected more than the collapse of communism: It heralded the advent of a satellite navigation technology initially developed by the United States for Cold War military missions.
Known as the Global Positioning System, the $10-billion network of satellites allows its users to determine their location anywhere on Earth with pinpoint precision. Within a few years, and certainly by the turn of the century, it should enable commercial air travelers to enjoy faster, safer and cheaper flights, government and industry officials say.
GPS is the first major Cold War military system to be made available for potentially lucrative civilian applications. The private sector has responded with a flurry of projects to exploit its commercial potential. Japanese luxury-car makers, for example, reportedly are installing dashboard-mounted GPS systems at a rate of 10,000 a month to enable affluent motorists to determine their precise location in Tokyo’s labyrinthine street system. The units combine GPS data with street map information contained on a hard disk and display the results on a video screen.
But the explosion of interest in GPS has created new friction between military and civilian users. The Pentagon appears determined to reserve the right to scramble the signals so they cannot be used by hostile forces, while civilians want access to clear signals at all times.
With GPS, pilots can determine their exact location, give or take a few yards, as well as their speed and direction at any time. That degree of precision will make it possible to substantially improve the capacity, efficiency and safety of the current air traffic control system.
The revolutionary impact of satellite navigation on air traffic control will be “as significant or more significant as personal computers to business,” said Thomas C. Richards, head of the Federal Aviation Administration.
Instead of flying within specified “highways in the sky,” which tend to reflect the location of ground radar stations rather than the most efficient flight paths, airliners using GPS will be able to take the most direct route to their destinations.
They will also be able to fly much closer to each other--without compromising safety considerations--across expanses of ocean and sparsely populated regions such as Siberia and China, where the absence of radar and radio guidance beacons now requires wide spacing.
Marc Mosier, a member of Arc en Ciel (Rainbow in the Sky), the French club that sponsored the air race, noted that for eastbound aircraft, the first ground-based radio navigation station after Moscow is in Nome, Alaska, some 6,000 miles away. “There is virtually nothing in between,” Mosier said. “This race just would not have been possible without GPS.”
The system’s capabilities astonished the Russians. In Yakutsk, deep in Siberia, race organizers traded two book-sized GPS receivers, each of which cost about $2,500, for the landing fees, fuel and services for the 28 private planes participating in the event. Although the Soviet Union developed a comparable satellite navigation system for its military, none of the equipment is in civilian hands there.
“We demonstrated GPS receivers for them by just walking along,” recalled Tom Haines, a race observer and member of the Aircraft Owners and Pilots Assn. “It told them they were moving on a runway in Siberia at 3 kilometers an hour, and they were just astounded.”
Over time, GPS will relocate air traffic control functions from the ground to space. It will significantly increase the capacity of air corridors, particularly those used for transoceanic flights. Today, planes crossing oceans are spaced 60 to 120 miles apart for safety’s sake because they are not within “controlled” airspace. Satellite navigation will allow them to fly as close as five miles apart.
Aircraft using GPS equipment will be continuously and automatically monitored. So the possibility of an airliner straying off course will be reduced considerably.
GPS will enable planes to land in moderately adverse weather at smaller airports in Third World nations, as well as the United States and Europe. In smaller fields without instrument landing systems, navigation satellites can steer planes close enough to land when clouds are as low as 200 feet, said FAA Associate Administrator Martin T. Pozesky.
In poorer weather conditions, more elaborate equipment at airports and on planes will probably still be needed. The FAA and its counterparts abroad are planning to modernize existing instrument landing systems with more sophisticated microwave landing systems. But U.S. airlines want to assess the potential of GPS navigation before committing to buy expensive MLS equipment for their aircraft.
Besides obviating the need for some instrument landing systems, GPS has the potential to render obsolete many of the 39 new radar systems now being installed in the United States at a cost of $400 million under the FAA’s air traffic control modernization program. Pozesky insists that these systems will remain useful for 20 years, but other experts believe that they will succumb quickly to satellite navigation.
Although GPS will replace many radar sets, it operates differently. When the system is fully operational, 24 satellites will beam signals from fixed locations 10,900 miles above the Earth’s surface. No matter where he or she is, a user will be able to receive simultaneous signals from at least four satellites.
Based on the travel time of the signals, a GPS receiver can calculate with extreme precision its distance from each of the four satellites. It then determines its precise location and altitude, employing a high-tech version of the “triangulation” system used for centuries by surveyors.
Because more direct routes and shorter flight times translate into lower fuel bills for airlines, GPS should lead to lower fares for many of the nation’s 1.2 million daily airline passengers. One airline estimated that GPS equipment would generate savings of $283,000 per month for each of its transoceanic aircraft.
Much of the new momentum for GPS reflects its great success in directing American military forces during Operation Desert Storm, even though the system is not yet fully in place.
GPS guided virtually all mobile American forces to their targets, from personnel carriers to F-117 Stealth fighters. The system will become fully operational late next year when the final six satellites are launched, completing the full constellation of 24 satellites. The FAA expects airliners to begin using them routinely by mid-1995.
Guidance From a War Hero
The satellite system that guided U.S. forces in Desert Storm will soon direct commercial airliners, which currently rely on ground-based systems.
1. Plane receives signals from four satellites locked in 10,900-mile orbits.
2. Using the space equivalent of triangulation, the plane’s on-board receiver establishes the aircraft’s position based on how long it takes the signal to arrive.
3. Plane’s position is then relayed by a separate communication satellite to ground control.
No More Zigzags: Under the current navigation system, planes must veer from ground radar station to ground radar station. The new system will allow direct flight paths.
The Benefits
* Shorter flight times because of more direct routes.
* Lower fuel costs.
* Less chance of airliners straying off course.
Source: FAA
