Research And Implementation Of Adaptive Anti-jamming Algorithm For Navigation Receiver

With its high-precision,real-time,and all-weather positioning features,satellite navigation systems are not only widely used in civil fields such as atmospheric observation,traffic navigation,and engineering surveys,but also play a pivotal role in military struggles.The satellite navigation system strategy is of great significance.Various countries are vigorously carrying out research on satellite navigation technology.Whoever occupies the commanding heights of satellite navigation technology will take the lead.However,when the satellite signal reaches the surface,its power is extremely low,and there are all kinds of interference in the environment,so it is very important to conduct anti-jamming research on satellite navigation to ensure that the navigation signal is correctly received by the receiver.Under the above background,the research of adaptive anti-interference algorithm is carried out,and the design of anti-interference system is completed on the hardware platform.The main work of the thesis is as follows:1.In this thesis,the GPS system is taken as an example,the composition of the GPS system is introduced,the composition of the GPS signal and its vulnerability are analyzed,the types of navigation interference and various navigation anti-jamming technologies are briefly described.2.The composition of the navigation anti-jamming system is briefly summarized,several common antenna array models are introduced,and a concentric circular array model is proposed.Several classic adaptive algorithms are compared,the LMS algorithm is analyzed in detail,and the selection of the step size factor of the LMS algorithm is theoretically analyzed.3.The power inversion algorithm is proposed,and two common power inversion algorithm analysis models including the minimum mean square error model based on the reference signal and the linearly constrained minimum power model are derived and analyzed in order to verify the unity of the two models.The anti-interference performance of several adaptive algorithms based on power inversion is compared,and the influence of antenna arrays,the number of array elements,the distance between array elements,and the power of the interference signal on the anti-interference performance of the algorithm are explored.Aiming at the problem of the limited freedom of spatial filtering,the space-time adaptive filtering is studied.The influence of the number of delay taps on the space-time adaptive anti-jamming algorithm is explored,and it is verified that the space-time adaptive anti-jamming algorithm has a higher degree of freedom than spatial anti-interference algorithm under the same number of array elements and has the ability to distinguish interference signals of different frequencies.4.The four-element Y-shaped array is selected as the antenna array.Based on the power inversion algorithm,the design of the adaptive anti-interference system is completed on the FPGA hardware platform.The design ideas of each module of the system are introduced,and the adaptive algorithm module is emphatically analyzed.The simulation results of the system are analyzed in conjunction with MATLAB.The simulation results show that the system designed in this thesis can effectively suppressed not only narrowband interference but also wideband interference.