Research On Interference Suppression Algorithm For Beidou Navigation Receiver Based On Space-time Adaptive Processing

Beidou satellite navigation system is a global satellite navigation system,which has been developed and operated independently.With the increasing application of Beidou navigation satellite system,people have higher requirements on the accuracy and reliability of the navigation system,especially in the battlefield environment where Beidou navigation system is most widely used and exists a variety of interference.In order to make the Beidou navigation receivers work in the complex interference environment normally and efficiently,it is necessary to improve the disturbance rejection performance of the navigation system.Due to the limitation of the number of array elements in the space anti-jamming scheme,it can not suppress a large number of broadband interference effectively.In this thesis,we do some research on the space-time interference suppression algorithm.Based on the spatial filtering,the algorithm increase the same number of time taps on each element,so as to increase the number of interference and improve the anti-jamming performance.Firstly,the thesis studies the common interference signal of the satellite navigation receivers and do some researches on the typical anti-jamming methods involving time domain,frequency domain and spatial domain.For the limitations of these algorithms,we mainly study the space-time joint interference suppression algorithm.Several kinds of typical algorithms of space-time adaptive processing methods are discussed in this thesis and then the LMS algorithm are mainly studied.Due to the fixed step factor of traditional LMS algorithm,the convergence speed and steady-state error of the algorithm are affected.Then the normalized LMS algorithm is used to process step factor.Simulation results show that the normalized LMS algorithm has better performance and it can be applied to the space-time adaptive interference suppression algorithm.The space-time adaptive interference model are made with Matlab simulation platform.The satellite signal and the interference that produced by jammeer are the system inputs and the outputs can be obtained after the process of each module.Through comparing the input and output signals and calculating cancellation ratio,we conclude that the space-time adaptive algorithm can suppress the wideband interference more effectively.Finally,the influence factors of the anti-jamming are discussed with the Matlab.