Adaptive Interference Nulling Antenna

Satellite navigation system can provide a sophisticated three-dimensional coordinates, speed and time. But signals in the satellite navigation annihilate in noises, and it's easy to be interfered. Therefore, anti-jamming play a key role in satellite navigation system. Among so many anti-jamming technologies, adaptive anti-jamming nulling antenna is the best anti-jamming performance. This dissertation makes a research in the adaptive anti-jamming nulling antenna.The main contents are as follow:Chapter 1 introduces the relevant technologies and the developments of the adaptive Anti-jamming nulling antenna. A brief introduction is made based on some recent references and documents, as well as the researches, discussions and comparisons on the domestic and foreign adaptive Anti-jamming nulling antenna technology development.Basic theories and composing of the adaptive antenna are discussed in Chapter 2, mainly on the principles of the adaptive antennas, the demonstrations of the antenna beam-forming way and the comparisons on the analogue and digital receiving system. We decided to use a digital receiving system in the adaptive receiving system, and analyzed its composing and how it works.The researches of the adaptive algorithms are presented in Chapter 3. The research of adaptive algorithms is uppermost in Adaptive antenna .We decided to use the power inversion array algorithm. this algorithm can restrain the interference, the stronger interference is, the better algorithm works. By comparing several convergent algorithms, RLS algorithm which has faster convergence and is less impact by the beam synthesis system has been chosen and simulated, the result of simulation comes up to the standards. Also, we analyze antenna array mutual coupling algorithm effects, and use the mutual coupling coefficient's inverse matrix to calibrate mutual coupling. Analyze its effect on the algorithm, which comes from the inconsistencies of the amplitude and phase of the receiving system , quantify its average value, estimate the size of the inconstancy that the system allows, which has no effect on the algorithm. Chapter 4 discusses the element of array and antenna array in system. Array element choice, in order to achieve the small circular polarization request, selects the microstrip antennas. Using high relative permittivity substrate and four slots of equal arm lengths are embedded in the patch to low antenna resonance frequency, compared to conventional antenna of the same size. Circularly polarized (CP) radiation of microstrip antenna can be achieved by using a single probe feed at the diagonal line of the patch and truncating corners. We carried out antenna element's simulation and test, and the results achieved indicator. Analyses of processing tolerance and processing debugging have also been made. Circular array whose array element is 4 has been chosen and simulated according to the analysis of the antenna array.In this study, we researched on some recent domestic and foreign references and documents, we selected and designed the corresponding receiver system, adaptive algorithms, and the element of the adaptive antenna array and antenna array, the various parts of antenna system is simulated and tested, the results of this study show that the indicators of the adaptive antenna system fully meet the requirements.