Stanford University Launches New Center Dedicated To GPS Research
"Research at the Stanford Center for Position, Navigation, and Time (SCPNT) is aimed at vastly extending and expanding the already revolutionary benefits of GPS in society," said Per Enge, the center's research director and a professor of aeronautics and astronautics in the School of Engineering. "Supplementing the system's reach, accuracy, and resistance to radio frequency interference would make possible diverse new applications such as automated aircraft landing, location-based encryption and eradicating unexploded ordnance."
Stanford has both a long track record in GPS research and innovative new ideas for the future of spatial information technology. Two of the center's founding faculty, Bradford Parkinson and James Spilker, were prominent architects of the original GPS. Parkinson, Spilker and Enge join faculty from five academic departments with vital expertise in the new technologies that will be required to build on GPS: aeronautics and astronautics, applied physics, electrical engineering, mechanical engineering and physics.
Faculty members include: Umran Inan (electrical engineering), Mark Kasevich (applied physics and physics), Arogyaswami Paulraj (electrical engineering), Abdul Bahai (electrical engineering) and Tom Kenny (mechanical engineering). Tom Langenstein, currently the deputy program manager of the soon to be completed Gravity Probe B program, is the executive director of the new center. In addition, the center expects to add at least one new faculty position within the next year.
New technologies and applications
Since Stanford led the development and deployment of the widely used error correction system called the Wide Area Augmentation System (WAAS) in 2003, the main limitation to GPS has become loss of signal for either of two reasons: an obstructed line of sight or radio interference (malevolent interference is known as "jamming"). Research at the SCPNT will address both problems.
SCPNT researchers are already looking at techniques to get the maximum benefit from the new signals to be available from GPS satellites. To date, civilians have only had total access to signals at one frequency. In the next decade, GPS will begin to broadcast signals at three frequencies for civilians. In addition, SCPNT will leverage the signals from the Russian satellite navigation system, called GLONASS; the upcoming system from Japan, called QZSS; and the signals from Galileo under development by Europe.
Particular concentration will be on the signal structure and the design of methods to simultaneously use both Galileo and GPS. The result should be increased system accuracy, availability and integrity for users worldwide.
In addition, researchers are working to develop "smart" antennas that can weaken a jamming signal relative to the legitimate signal from any of these satellites. The SCPNT is also already working with the United States Navy on a precision automated airplane landing technology called JPALS that takes advantage of advanced antennas as well as the two frequencies already available to military users of GPS.
SCPNT researchers are also developing several technologies to compensate for temporary signal losses. Among the solutions are new micro electromechanical systems (MEMS) and atom-based sensors, including accelerometers and gyroscopes (to measure movement) and oscillators (to measure time) that can be embedded in GPS receivers. When a GPS signal is lost the sensors can continue providing position and time information by recording the receiver's movement since the last signal was received.
To ensure that these robust receivers are also inexpensive, the SCPNT is working to develop lower power GPS integrated circuits. These receivers will also leverage signals from other radio sources like television stations and existing radio navigation systems such as Loran.
In addition to developing the WAAS for the Federal Aviation Administration and JPALS for the Navy, Stanford is also working to deploy a complementary Local Area Augmentation System (LAAS) that will be used at major airports. By providing decimeter accuracy, the LAAS will allow jetliners to land fully automatically when needed.
High-resolution position technology could also aid in the humanitarian task of finding and safely clearing buried landmines and ordnance. A metal detector that can sense position down to a few centimeters could determine whether a buried piece of metal has the shape of an unexploded shell or is merely the small, irregular fragment of one that has already exploded.
Industrial Affiliates Program
Enge said many future projects at the new center will have direct applications for private industry, including defense, transportation and even entertainment companies. For example, location-based encryption, a method of securing data based on its geographic position, has applications for digital rights management of sensitive media content such as movies.
SCPNT welcomes private industry's participation in the Center's research, Enge says. "Membership in the Center's Industrial Affiliates Program will provide many benefits, including: advising on research, sponsoring graduate students, on-site Visiting Fellow privileges, and early exposure to the Center's Intellectual Property," he adds. Interested companies should contact Enge, Spilker or Langenstein.
"Society has still only begun to tap the potential of GPS, much less the enhancements we are working on at the center," says Spilker. "Stanford has both the track record and the expertise to help develop this potential for a wide variety of applications including ones no one has imagined yet."
SOURCE: Stanford School of Engineering