Design of smart antenna array for interference suppression in GPS

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2016
Dabak, Ömer Can
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GPS jammers add excessive noise to received low power GPS signals and have capability to weaken or completely destroy the positioning performance of GPS receivers. The most popular technique to overcome GPS jamming problem is suppression of jammers by using array signal processing techniques. In this thesis, a GPS anti-jamming system is constructed by designing an active antenna array and implementing adaptive beamforming techniques. This thesis mainly include the design of four element active circularly polarized microstrip antenna array, implementation of beamforming techniques and presentation of experimental results obtained from the constructed GPS anti-jamming system. In active antenna array design, circularly polarized operation of the array element is achieved through nearly square microstrip patch antenna structure. After verification of the design by comparing simulation and measurement results, four element planar array is designed and manufactured. Then, four channel LNA card design and production is performed in order to obtain a compact active antenna array. All electromagnetic simulation and parametric analysis of the antennas are performed in electromagnetic simulation tool CST Microwave Studio. In beamforming section, two main beamforming methods that are Capon beamforming and null steering are studied with theory and simulation results obtained from the code developed in MATLAB environment. The jammer suppression success of the constructed system is demonstrated by scenarios that include real satellites and a continuous wave jammer source.
Radio frequency microelectromechanical systems., Microelectromechanical systems., Antennas (Electronics).
http://etd.lib.metu.edu.tr/upload/12620150/index.pdf
https://hdl.handle.net/11511/25756
Graduate School of Natural and Applied Sciences, Thesis
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