| Summary ： |
Positioning a mobile station (MS) with a wireless communication system in a non-line-of-sight (NLOS) environment, which is sometimes called ”NLOS geolocation” for short, has become an important issue with the rapid development of mobile communications in recent years. Here we present a unified analysis for NLOS geolocation, where major techniques, i.e., the time of arrival (TOA), time difference of arrival (TDOA), angle of arrival (AOA) and signal strength (SS) based schemes are investigated in a coherent manner. From the viewpoint of estimation theory, we intend to answer two basic questions of this subject: what is the best achievable positioning accuracy; and how to achieve it? We shall focus on the analysis of the simplest case, TOA positioning in a (LOS or NLOS) single-path environment, to outline a typical framework of the analysis. The elements of parameter estimation of estimation theory and matrix manipulation are two main tools in our discussion. However, we shall emphasize on the physical and intuitive interpretation of the development. No prior knowledge on those subjects or complicated details will be involved. |
Dr. Yihong Qi had visited our laboratory on July 2, 2004. She is a post-doctoral student of Princeton University and currently staying in NTT DoCoMo Wireless Laboratories. She had presented of the positioning technique for mobile communication systems. The meeting had 15 participants including students from Kagawa University, and had Q&A actively. Details are as follows.
