Title of dissertation TIME-BASED LOCATION TECHNIQUES USING INEXPENSIVE, UNSYNCHRONIZED CLOCKS IN WIRELESS NETWORKS Matthew Yew Mun Mah, Doctor of Philosophy, 2011 Dissertation directed by Professor Ashok Agrawala Department of Computer Science The ability to measure location using time of flight in IEEE 802.11 networks is impeded by the standard clock resolution, imprecise synchronization of th...

The conventional global positioning system (GPS) can often fail to provide position determination for a mobile user in indoor and urban environments. To cope with GPS failure in such environments, a new navigation system which utilizes a terrestrial digital multimedia broadcasting (T-DMB) signal to obtain the mobile user's position is presented. Since the T-DMB transmitters in Korea construct a...

Microseismic signals are generally considered to follow the Gauss distribution. A comparison of the dynamic characteristics of sample variance and the symmetry of microseismic signals with the signals which follows α-stable 10 distribution, reveals that the pulse characteristics of the microseismic signal is outstanding and that the probability density curve of the microseismic signal is approx...

We present an approach for the localization of passive nodes in a communication network using ambient radio or sound signals. In our settings, the communication nodes have unknown positions. They do not emit signals for localization and exchange only the time points when environmental signals are received: the time differences of arrival (TDOA). The signals occur at distant but unknown position...

We present an approach for the localization of passive receiver nodes in a communication network. The only source of information is the time when environmental sound or ultrasound signals are received. The discrete signals occur at unknown positions and times, but they can be distinguished. The clocks of the receivers are synchronized, so the time differences of arrival (TDOA) of the signals ca...

Direction of arrival (DOA) and time difference (TDOA) hybrid localisation is an effective technique. Station position errors affect performance. Owing to the highly non-linear nature problem, there are few methods DOA/TDOA in presence station errors. Hence, iterative constrained weighted least squares (ICWLS) algorithm proposed estimate locations multiple targets stations for with To ensure con...

We present two approaches for the localization of passive nodes in a communication network using ambient radio or sound signals. In our settings the communication nodes have unknown positions. They are synchronized but do not emit signals for localization and exchange only the time points when environmental signals are received. The signals occur at unknown positions and times, but can be disti...

Microphone arrays are widely employed for applications like teleconferencing, high quality sound capture, speaker recognition/identification, acoustic surveillance, head aid devices, speech acquisition in automobile environments etc. For all these applications the benefits that a microphone array provides over a single microphone are two fold. First using a microphone array we can localize a so...

For the problem of estimating time difference of arrival (TDOA) of radio waves impinging on a pair of antennas for the purpose of passively locating the source of a communications or telemetry signal in the presence of interfering signals and noise, a new class of signal-selective algorithms that are highly tolerant to interference and noise is introduced. In part I of this two-part paper, the ...

A hybrid TDOA/AOA positioning technique for indoor ultra wideband (UWB) systems is presented in this paper. The UWB system is a potential candidate for improving the location accuracy of indoor positioning due to the fine-resolution characteristic of the UWB signals. The hybrid technique consists of extended Kalman filters (EKF’s), which process time difference of arrival (TDOA) and angle of ar...