Waveguide Electric Field Sensor Array Signal Processing Techniques

With the rapid development of electronics and commumication technology, the requirement for sensors is more complicated. Integrated optical waveguide electric field sensor array using advanced integrated optics technology can be adopted which makes the whole measurement system small,steady and reliable, is characteristic of broad bandwidth, immunity to electromagnetics and tiny perturbation.The electric field sensor using integrated optics technology based on LiNbO3 substrate is becoming a research focus.The optical waveguide electric field sensor can be applied in these fileds:electric field measurement, far field and near field direction pattern measurement of antenna and new receiving antenna.Direction of arrival estimation and localization of signal sources using sensors array have wide applications in radar,passive sonar and communication system.Signal processing technology based on optical waveguide electric field sensor array has intensive research in theory and important application in engineering.This dissertation involves estimation of signal parameters based on optical waveguide electric field sensor array.Introduce the principle and system model of optical waveguide electric field sensor.The classical DOA estimation algorithms based on sensor array are analyzed.The DOA estimation algorithm and detection of source number algorithm under colored noise fields are studied.The algorithms of source number estimation in colored noise are presented: The eigenvalues modified difference method and signal number estimation based on higher order cumulate The eigenvalues modified difference method reduces the dispersibility of the eigenvalues caused by colored noise.There is no limits for the noise model.It works effectively via computer simulation.Anthoer solution based on four order cumulate suppresses the gaussian noises by higher order cumulate.It determinates the signal numbers by main eigenvalue number through four order cumulants matrix.Its disadvantage is the large calculation. Two DOA estimation algorithms in the presence of colored noise are proposed: The spatial smoothing difference method and The maxeigenvalue differencing method.The spatial smoothing difference method eliminates the impact of colored noise by differernce matrix,detects the correlated sources by spatial smoothing. The maxeigenvalue differencing method eliminates colored noise because the difference matrix has no information of noise, removes the interference of correlated signals by largest eigenvalue.Computer simulation verifies the correctness of this method.