Time-Difference-of-Arrival (TDOA) location estimation is central to an OFDM based Precision Personnel Locator system being developed at WPI. Here we describe a component of the effort towards characterizing the performance of such a system and verifying the functionality of hardware and software implementations. The performance degradations due to noise in the received signal and misalignments between transmitter and receiver clock and heterodyne frequencies are investigated. This investigation involves development of a MATLAB simulator for the entire system, experimental measures using a prototype implementation and linearized analytic analysis of specific subsystems. The three types of characterizations are compared, confirming agreement, and analytic results are used to demonstrate construction of a system engineering design tool.

Accurate indoor geolocation is an important and novel emerging technology for commercial, public safety, and military applications. Since most wireless communication systems used for indoor position location may suffer from dense multipath situation, which leads to a severe degradation of position accuracy. The improved TDOA/AOA(Time Difference of Arrival/ Angle of Arrival) position location for indoor ultra-wide band (UWB) systems in the thesis improves the position accuracy of indoor location by using fine resolution of UWB signals. In the line of sight situation, by means of increasing angle of arrival (AOA) information to time difference of arrival (TDOA) based location to achieve the goal of accurate indoor geolocation and provides non-line of sight (NLOS) error mitigation for time measurement and AOA selection to suppress the impact to position accuracy in NLOS environment. Finally, the extended Kalman filter is used to perform position tracking of the target. In the simulations, the NLOS error in time measurement is produced according to the characteristics of indoor UWB channel. Several assumptions of NLOS errors are made in angular measurement. It is observed that proposed method efficiently mitigates the position error in NLOS environment, and detect if the NLOS exists between base station and mobile station immediately.

Thesis (Pd. D.)--Worcester Polytechnic Institute. / Keywords: channel measurement; location finding; indoor geolocation; TOA; super-resolution. Includes bibliographical references (p. 165-171).

Dissertation (Ph.D.)--Worcester Polytechnic Institute. / Keywords: Ray Tracing; Wideband Measurement; Dynamic Modeling of Ranging Error; ToA-Based Indoor Localization; NLoS Identification. Includes bibliographical references (leaves 147-159).

Dissertation (Ph.D.)--Worcester Polytechnic Institute. / Keywords: RF system design; indoor positioning. Includes bibliographical references (leaves 270).

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: TDOA; indoor geolocation; TOA. Includes bibliographical references (p.55).

Dissertation (Ph.D.) -- Worcester Polytechnic Institute. / Keywords: OFDM; signal structure; CDMA; FDMA; indoor geolocation. Includes bibliographical references (p 390-408).

Dissertation (Ph.D.) -- Worcester Polytechnic Institute. / Keywords: localization; indoor geolocation; indoor radio channel. Includes bibliographical references (p. 120-125).

No description available.

Recently, there are great interests in the location-based applications and the location-awareness of mobile wireless systems in indoor areas, which require accurate location estimation in indoor environments. The traditional geolocation systems such as the GPS are not designed for indoor applications, and cannot provide accurate location estimation in indoor environments. Therefore, there is a need for new location finding techniques and systems for indoor geolocation applications. In this thesis, a wide variety of technical aspects and challenging issues involved in the design and performance evaluation of indoor geolocation systems are presented first. Then the TOA estimation techniques are studied in details for use in indoor multipath channels, including the maximum-likelihood technique, the MUSIC super-resolution technique, and diversity techniques as well as various issues involved in the practical implementation. It is shown that due to the complexity of indoor radio propagation channels, dramatically large estimation errors may occur with the traditional techniques, and the super-resolution techniques can significantly improve the performance of the TOA estimation in indoor environments. Also, diversity techniques, especially the frequency-diversity with the CMDCS, can further improve the performance of the super-resolution techniques.