Performance Evaluation of the RF Receiver for Precision Positioning System Hemish K. Parikh, Student Member ION, William R. Michalson, Member ION, R. James Duckworth Electrical and Computer Engineering Department, Worcester Polytechnic Institute BIOGRAPHY Hemish K. Parikh is a research assistant at Center for Advanced Integrated Radio Navigation (CAIRN) at Worcester Polytechnic Institute. He received his Bachelors degree in Electronic and Telecommunication Engineering form Bombay University, India in 2000 and M.S degree form University of Missouri - Columbia in 2002. He is currently pursuing his PhD in the ECE department at WPI. His research interest includes indoor precision position location systems and is currently involved in developing RF transmitter and receiver systems. Dr. William R. Michalson is an Associate Professor in the ECE Department at the Worcester Polytechnic Institute where he performs research and teaches in the areas of navigation, communications and computer system design. He supervises the WPI Center for Advanced Integrated Radio Navigation (CAIRN) and is the Director of the WPI Bioengineering Institute's Center for Untethered Healthcare. His research focuses on the development, test, and evaluation of systems, which combine communications and navigation. He has been involved with navigation projects for both civilian and military applications with a special emphasis on navigation and communication techniques in indoor, underground or otherwise GPS-deprived situations. Prior to joining the faculty at WPI, Dr. Michalson spent approximately 12 years at the Raytheon Company where he was involved with the development of embedded computers for guidance, communications and data processing systems for both space borne and terrestrial applications. Dr. R. James Duckworth is an Associate Professor in the Electrical and Computer Engineering department at WPI. He obtained his PhD in parallel processing from the University of Nottingham in England. He joined WPI in 1987. Duckworth teaches undergraduate and graduate course in computer engineering focusing on microprocessor and digital system design including using VHDL and Verilog for synthesis and modeling. His main research area is embedded system design. He has worked as a consultant for many companies on a wide variety of embedded system related projects. He is a member of the IEE, IEEE, and BCS and is a Chartered Engineer of the Engineering Council of the UK. ABSTRACT One of the major drivers for developing integrated navigation systems is the vision to provide first responders and healthcare providers, critical information where and when they need it. These integrated wireless devices of the future will assist the user with communications and incident management operations in the field in real time. The most important piece of such a system is clearly a ability to track and locate these wireless devices with high precision in a high-multipath environment. A previous paper presented a novel method for precise geolocation in indoor environments using an orthogonal frequency domain multiplexed (OFDM) signal consisting of many sinusoidal sub-carriers [1]. Unlike the ultra wideband signals that are often proposed for performing precision location in high multipath environments, the proposed signal structure is easily adapted to conform to existing spectral allocations. Further, the signal structure is capable of being used in coded orthogonal frequency domain multiplexing (COFDM) systems for supporting communications and navigation concurrently on the same radio channel. This technique is also well suited for use on ad hoc wireless networks, allowing the precision location of wireless nodes with respect to one another. This OFDM-based technique was first demonstrated using audio frequency signals rather than RF signals and is currently being implemented at RF. The focus of this paper is the design and performance evaluation of the RF front end receiver structure being developed for precision location system using this multi- carrier technique. The effect on the precision of the location estimate due to RF receiver design imperfections will be assessed and design issues for future receiver design improvements will be reviewed. INTRODUCTION An advanced personnel location and navigation system can be used in various applications; however the system 1908 ION GNSS 17th International Technical Meeting of the Satellite Division, 21-24 Sept. 2004, Long Beach, CA