الفهرس 
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Abstract
This thesis is mainly concerned with a vital issue in navigation systems.
Generally, navigation systems comprise gyroscopes. Hence, the treatment of the
gyroscope signals is very important for navigation applications. The gyroscope
itself is a sensor that is used to measure the rotation rate of a moving equipment.
This rotation rate is important for direction estimation of the moving equipment.
There are different types of gyroscopes including mechanical, micro-electromechanical,
and optical gyroscopes.
In the optical gyroscope, an optical coil is used as a sensor for the light
emitted from the source and passed through a directional coupler. The returned
optical signal from the coil is passed again through the optical directional coupler
to the receiving optical detector. Generally, the light entering the coil is split into
two beams that go through two paths of equal length with the rotation of the
equipment, the two path lengths differ inducing phase shift. The path difference
is estimated from the signal received by the detector. This effect is called Sagnac
effect. The received optical signal is converted to an electrical signal that may
be noisy.
The work in this thesis is limited to the noise reduction problem in optical
gyroscope signals. Different approaches are presented and compared for efficient
noise reduction of gyroscope signals. Both Kalman filtering and wavelet
denoising are studied in this thesis for gyroscope noise reduction. In addition,
hybrid structures based on both approaches are presented for the task of noise
reduction. Simulation results prove that the hybrid structure based on cascaded
Kalman filtering and wavelet denoising achieves good performance in signal to
noise ratio (SNR) improvement of gyroscope signals.