GPS researchers aim for pinpoint accuracy (Stanford, USA)


The task of finding land mines could become much easier because a metal detector could not only find a metal object accurately, but determine its shape underneath the ground so it can be safely tracked and removed. Per Enge believes the military could create a small robot helicopter with a one-yard rotor span that could fly over unexploded mines and map them for soldiers to see.


(07.11.2005)

Stanford professors want to make navigation an exact science, tracking objects by centimeter

Ancient navigators once looked to the stars to find out where they were. Today, people still look to the sky for the same purpose, but they're getting the information from satellites, not the stars.

A group of Stanford University academics wants to make such navigation so accurate that it could tell whether you are in your car or standing next to it.

Since the U.S. government first launched a satellite navigation system known as the global positioning system in 1978, the system's ability to pinpoint the location of an object has steadily improved.

GPS receivers were bigger than a brick a decade ago and were accurate to within about 100 meters. Today a hand-held $100 GPS receiver can fix a point on the ground within 10 meters, while more expensive military systems can zero in on the receiver within 5 meters.

But the GPS system doesn't get much better than that, and it doesn't work indoors or in deep urban canyons where a target object isn't in the line of sight of two or more satellite. And jamming GPS signals isn't that hard.

Such a system isn't good enough for James Spilker and Per Enge, who are among the founders of the Stanford Center for Position, Navigation and Time. Spilker, a founder of navigation chip startup Rosum and one of the creators of GPS, believes satellite navigation is just in its infancy.

``Technologies are coming to the forefront that will impact billions of people and millions of businesses,'' Spilker said. ``Our humble goal is to create the top-ranked university center in the world for this realm of technology.''

Within a centimeter

The interdisciplinary research center wants to create a navigation system capable of locating objects within 1 centimeter -- less than half an inch. The center hopes to achieve that goal within 20 years.

It already has a lot of ideas on how to make navigation systems much more accurate, said Enge, the center's research director and professor of aeronautics and astronautics.

Already, GPS navigation is being built into cars and cell phones to enable people to find the nearest restaurants or locate someone in need of 911 assistance. Tens of millions of people track their locations today. The business consulting firm Frost & Sullivan estimates that the market for GPS equipment sales could hit $10 billion by 2010, with consumers accounting for much of those sales.

The Stanford center has federal funding and is raising more money from commercial industry partners who could participate in the research effort.

``It's important to look ahead to the future while you're solving the problems of today,'' said Kanwar Chadha, founder of Sirf Technology, a GPS chip-design company that will probably join the effort. ``If they can get to centimeter accuracy in the open, then it means that in a difficult environment, they could maybe have a meter or so accuracy. And for a lot of consumer applications, that's going to be enough. If they can work to make it instantaneously, then that is also going to be very important.''

Better technology

Better satellite-based navigation technology is just one element of a system that could deliver pinpoint accuracy. Other elements come from a variety of disciplines and include inertial navigation, which is based on work by Stanford physicist Mark Kasevich. These sensors could be embedded in GPS receivers and detect tiny movements, broadcasting information about the object's location even when out of satellite detection.

Tom Kenny, a professor of mechanical engineering, also is working on silicon oscillators that could improve the reliability of a GPS device. And electrical engineering professors Umran Inan and Arogyaswami Paulraj are trying to create much smarter antennas to improve GPS reception in a variety of hard-to-locate places, even in the presence of jamming devices.

Spilker hopes that the system could be extended so it works both underwater and underground.

The technology could bring about astounding advances with commercial and military applications. With centimeter accuracy, bombs and missiles would almost never miss. Aircraft could land on carriers without the need for a pilot's steady hand.

The task of finding land mines could become much easier because a metal detector could not only find a metal object accurately, but determine its shape underneath the ground so it can be safely tracked and removed. Enge believes the military could create a small robot helicopter with a one-yard rotor span that could fly over unexploded mines and map them for soldiers to see.

Future of security

On the commercial front, Enge believes that something called ``geoencryption'' could become a reality. That's where someone logging into a computer would have to prove his or her location to access a computer. If someone logs in from the wrong location, a security alert could be sent.

Indoors, a better navigational system could sense and locate Alzheimer's patients in their homes and track their movements. If the patients do something out of character, such as failing to answer the telephone or move from one spot for hours, the system could send an alert to caregivers.

Katherine Albrecht, a privacy activist and founder of the anti-tracking group Caspian, said the center should also study the social implications of tracking technology. ``I would hate the idea of this being built into every Timex watch, and then they consider the implications for privacy,'' Albrecht said. ``These applications have benign uses, but the same technologies can be used for sinister purposes. It would be fabulous if you could turn it off.''

Enge acknowledged that with better location technology comes the responsibility of balancing privacy rights. Such systems could be abused in a variety of ways, but the founders believe the benefits outweigh the risks.

Von: 07 November 2005, http://www.ohio.com by Dean Takahashi, Knight Ridder Newspapers

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