Summary

The objective of this project was to implement an urban geolocation demonstrator. In the course of the project, it was discovered that due to severe multipath conditions in urban and indoor areas traditional GPS receivers are unable to provide an accurate measurement of the location of objects within the buildings.

Preliminary results of ray tracing simulation and initial measurements showed that in many situations the signal arriving from the direct path (DP) is not the strongest signal arriving at the receiver. Traditional receivers, however, lock to the path associated with the strongest received signal. Therefore, the estimated distance found with traditional receivers may correspond to an arbitrary distance that includes a number of reflections of the signal before it arrives at the receiver. This observation revealed a need for research in modeling of the indoor radio channel and design of new signal structures and algorithms for indoor geolocation that led to other indoor geolocation projects pursued at WPI.

The preliminary results of this project were presented in several DARPA open review workshops, two DARPA reports, and several pioneering papers and presentations.

Principle Investigators:

• Kaveh Pahlavan (CWINS)
• James Matthews (CWINS)
• Paul Creamer (TASC/Litton)
• Joseph Pizano (TASC/Litton)

Research Staff (CWINS):

• Jacques Beneat
• Prashant Krishnamurthy
• Ahmad Hatami
• Yan Xu
• Mirela Marku

Sponsor: DARPA (Suo/SAS) Project

Duration: June 1997 - January 1999

Publications:

• Prashant Krishnamurthy, PhD, 1999, Analysis and Modeling of the Wideband Radio Channel for Indoor Geolocation Applications.
• K. Pahlavan, P. Krishnamurthy and J. Beneat, “Wideband Radio Propagation Modeling for Indoor Geolocation Applications”, IEEE Communications Magazine, April 1998.
• J. Beneat, K. Pahlavan, and P. Krishnamurthy, "Radio Channel Characterization for Geolocation at 1 GHZ, 500MHZ, 90 MHZ, and 60 MHZ In SUO/SAS", Military Communications Conference Proceedings, MILCOM99, Atlantic City, NJ, November 1999.
• P. Krishnamurthy, and K. Pahlavan, "Distribution of Range Error and Radio Channel Distribution of Range and Radio Channel Modeling for Indoor Geolocation Applications", 10th Annual IEEE International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC'99), Osaka, Japan, September 12-15, 1999.
• P. Krishnamurthy, J. Beneat, M. Marku, and K. Pahlavan, "Modeling of the Wideband Indoor Radio Channel Geolocation Applications in Residential Areas", IEEE VTC'99, July 1999.
• P. Krishnamurthy, and K. Pahlavan, "Analysis of the Probability of Detecting the DLOS Path for Geolocation Applications in Indoor Areas", IEEE VTC'99, July 1999.
• P. Krishnamurthy, K. Pahlavan and J. Beneat, “Radio Propagation Modeling for Indoor Geolocation Applications”, IEEE PIMRC'98 Boston, MA, September 8-11, 1998.