Enhanced narrowband signal detection and estimation with a synthetic antenna array for location applications

The main focus of this thesis is to develop a practical signal processing method based on the synthetic array concept applied to handheld location systems to enhance signal detection and parameter estimation in multipath environments. The antenna array is synthesized by moving one or two antennas along an arbitrary spatial trajectory while snapshot data is being collected. The synthetic array concept is introduced to reduce cost and complexity, and to improve receiver portability. The synthetic array is implemented for two applications of the antenna array, namely as a diversity system to enhance signal detection performance in dense multipath environments, and in the form of an Angle Of Arrival (AOA) estimation application.;In specular multipath environments, in which case the multipath channel is correlated, an approach for AOA estimation based on the use of a synthetic array utilizing the Estimation of Signal Parameters via Rotational Invariance Techniques (ESPRIT) algorithm is proposed. Taking advantage of the rotational invariance property of the ESPRIT algorithm, the antenna array is synthesized by moving a two-channel receiver. With this scheme, the synthetic array trajectory estimation, which is normally performed by using controllable moving motors or external aiding sensors, is removed. Simulation and experimental results verify the applicability of the proposed method.;Signal reception in indoor environments is susceptible to deep fading and signal attenuation. An antenna array utilizing spatial diversity can be implemented to reduce fading margins and to improve the signal detection performance. The indoor detection performance of narrowband signals based on a single moving antenna operating as a synthetic array, as compared to that of a static antenna, is investigated. The synthetic array provides a diversity gain through a combination of received signals at each synthetic antenna element. The processing gain achievable through spatial combining of a synthetic antenna is considered from a general theoretical perspective. The performance of the proposed method is theoretically analyzed in terms of the probability of false alarm and the probability of detection. Extensive sets of measurements based on CDMA-IS 95 pilot signals and GPS L1 C/A signals using a static antenna and a synthetic array are used to experimentally verify these theoretical findings.