Location, Time and Context in Systems: Rover – An Example

November 15, 2006
Ashok K. Agrawala | University of Maryland

In order to make computing devices more useful to most of us the next challenge we face is that of deriving and integrating location, accurate time and other context information in an easy to use framework. In this talk we present several technologies that have been developed at the University of Maryland to address these issues.

For indoor and outdoor location determination we have developed three technologies, PinPoint, Horus, and Nuzzer. PinPoint uses the measurement of the time of flight to estimate the distance, without requiring synchronization of the clocks or using pair wise pinging, leading to a scalable, O(1) algorithm per node to localize N nodes. We have implemented and tested this approach using standard WiFi NICs and have obtained accuracies of the order of 5 feet while using 40 MHz clocks for timing. Horus uses the signal strength measurements and takes into account detailed characteristics of the signal resulting in accuracies of less than three feet indoors. Nuzzer technology also relies on the measurement of the signal strength but does not expect the person to be carrying any communication device, detecting the presence and location of a person as he/she enters a region in which WiFi is deployed.

Accurate timing requires accurate clock synchronization. We have developed techniques which permit the clocks in large networks (of Internet scale) to be synchronized to the accuracies of sub-microsecond.

We are integrating all these technologies in the framework of the Rover system which we will demonstrate during the presentation.

Speaker Details

Dr. Agrawala is a Professor of Computer Science and Electrical and Computer Engineering at the University of Maryland. In 2001, he started the Maryland Information and Network Dynamics (MIND) Lab which carries out research and development activities in partnership with the industry. He received a BE degree in 1963 and a ME in 1965 from the I.I.Sc, Bangalore; and a Master of Arts and a Ph.D. degree in Applied Mathematics from Harvard University in 1970. He joined the faculty of the University of Maryland in 1971. Prof. Agrawala is the author of seven books, 6 patents (awarded or pending), and over 240 papers and is a well recognized for his contributions to the research in distributed systems, real-time systems, computer networks, system performance, and wireless systems. His has developed unique ways of managing time, synchronizing and developing applications which use local clocks in distributed environments but still carry out global synchronous actions. He has developed location determination techniques which give highly accurate location in usual Wifi environments. Recently he formulated Information Dynamics as a framework for addressing the structure of large, complex systems. He is the Director of the MIND Lab which started in 2001 and works closely with the industry. The technologies developed in this lab have resulted in 4 startup companies in Maryland.Prof. Agrawala has participated in many government programs. Recently he worked with the NSF in planning of its GENI program, addressing the technology needs in the area of embedded applications of today and tomorrow and their implications to the communications infrastructure.Prof. Agrawala is a Fellow of the IEEE and AAAS, and Senior Member of the ACM