Volpe Journal Summer 2000
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Karen Van Dyke: the Volpe Center's GPS expert brings satellite outage reporting to the world
When Karen Van Dyke received her bachelor's degree in electrical engineering from the University of Lowell in 1988, she, like many of her classmates, considered pursuing a position at one of the local high-tech computer firms. Instead, she decided to spend the summer working with one of her professors, who was conducting research for the Volpe Center on the Global Positioning System (GPS), a navigation system based on an array of satellites that provides signals which allow users to accurately determine their positions. That summer project opened the door to a distinguished career. Twelve years later, Karen is a Senior Project Leader in the Center for Navigation, and one of the most respected GPS experts in the country.
Karen's career has spanned a period when GPS applications matured into critical components of the national transportation system. When she started, says Karen, "GPS was an evolving system and its applications for all modes of transportation were fairly new. I understood that it was going to be an expanding technology with wide-ranging impacts. That was exciting!" Little did she know how far it would take her. Today, she is helping to develop GPS systems for air safety, and sharing these new technologies with organizations around the globe.
Karen also is quick to describe how her preconceived ideas about working for the government were radically changed. As a recent graduate, she wondered whether work at the Volpe Center would give her the professional experience she was seeking. "You always think about government bureaucracy and paperwork, but what really sold me was when I came to visit Volpe and I met top-notch engineers and saw the work they were performing. It was so intriguing."
"GPS was an evolving system and its applications for all modes of transportation were fairly new. I understood that it was going to be an expanding technology with wide-ranging impacts. That was exciting!" |
One challenging aspect of GPS technology is the determination of where and when reliable navigation signals will be unavailable due to the configuration of satellites. Because it has serious implications for air safety, this issue is a major concern of the Federal Aviation Administration (FAA). Hence, in 1990, the FAA asked the Volpe Center to develop algorithms that would predict the availability of GPS integrity for oceanic through non-precision approach phases of flight.1
In response to the Federal Aviation Administration request, Karen and the Volpe Center project team, in conjunction with RTCA, Inc., developed Receiver Autonomous Integrity Monitoring and Fault Detection and Exclusion algorithms. The Volpe Center then applied those algorithms in order to predict when GPS signals would not be available for the different phases of flight.
Once the availability algorithms were developed, the Federal Aviation Administration and the US Air Force charged the Volpe Center with developing a method for disseminating satellite non-availability information to pilots during the pre-flight planning process.
"You always think about government bureaucracy and paperwork, but what really sold me was when I came to visit Volpe and I met top-notch engineers and saw the work they were performing. It was so intriguing." |
Karen led this project, and her team designed and implemented a GPS satellite outage reporting system that was integrated into the Federal Aviation Administration aeronautical information system and the Notice to Airmen system of the Department of Defense.
As an extension of this work, Karen is conducting availability and integrity studies for aviation applications of GPS and accompanying Wide Area and Local Area Augmentation Systems for all phases of flight, including precision approaches. The Federal Aviation Administration also has requested a methodology for incorporating these predictions into the Notice to Airmen system.
True to its name, GPS is a global system, and countries around the world have begun to address the issues of satellite availability for aviation. Many countries have approached the Volpe Center for assistance with developing similar satellite outage reporting systems for air navigation. As a national leader in this technology, Karen has had a wonderful opportunity to represent the Center and the United States as a "technology ambassador," sharing her technical expertise and advice with peers on three continents. Her project group has assisted Australia, Germany, and Chile with the development of systems similar to those designed for the Federal Aviation Administration. Other countries also have expressed an interest in using the services of the Volpe Center.
These international efforts have provided the Center for Navigation with valuable business experience and a fresh perspective on GPS technology. "The thing that struck me the most was that they have a completely different way of addressing the benefits that this technology can provide to them," says Karen about her Australian colleagues. "They spend a lot of time researching cost-effective methods and looking for innovative, low-cost solutions. From a technology standpoint, it is refreshing to see that ingenuity." Karen is confident that there is a great deal to learn from researchers around the world, and she views each international assignment as an opportunity to both share information and gain new ideas.
In addition to her role at the Volpe Center, Karen is dedicated to the advancement of GPS technology nationwide. She currently serves as the President of the Institute of Navigation, a nonprofit professional society dedicated to the advancement of the art and science of navigation.
She has been on their council since 1992 as the Air Navigation Technical Representative and also has served as the Eastern Region Representative. The Institute of Navigation serves a diverse international community of technical experts and others interested in navigation and position determination for air, space, marine, and land applications.
Karen has published more than a dozen papers on GPS and is a co-author of the book, Understanding GPS: Principles and Applications, a 1996 reference text on GPS that includes information on markets and applications of products and services based on satellite navigation. She now holds a master's degree in electrical engineering from the University of Massachusetts at Lowell. For more information on the work that Karen has been doing, and her accomplishments, see the GPS story in this issue of the Volpe Journal.
1 For more information on the phases of flight, see the accompanying article on GPS. Back to Story