Research On The Adaptive Anti-jamming Processing Of Navigation Antenna Array

The global satellite navigation system can provide users with 24-hour three-dimensional coordinates,speed and time information at any location in terrestrial space.It is widely used in many fields such as scientific research and agriculture.However,due to the weak satellite signals and the increasingly complex environment where the navigation receiver is located,navigation receiver is highly susceptible to electromagnetic interferences.So the anti-jamming technique is becoming more and more important.Aiming at adaptive anti-jamming technology under different interference signals,this thesis combines the methods of theory,simulation and experiment.Firstly,for the reception of navigation signals,this thesis studies the design of the navigation terminal antenna.A circularly polarized microstrip antenna that can be applied to the navigation terminal is designed based on antenna design technology.On the basis of circularly polarized microstrip antenna studies,a 7-element antenna array is created.Then,it analyzes the isolation performance of antenna and optimizes the structure.The results show that the return loss and pattern performance of the seven-element circular array are good,which could verify the effectiveness of the design.Then,the accurate estimation of the interference DOA is required before the adaptive anti-jamming algorithm.The thesis also studies the two-dimension DOA estimation algorithm for narrowband signals under uniform circular array and its performance.Furthermore,after analyzing planar array signal models.the adaptive algorithm with a 7-element antenna array is chosen.After the comparison between the power inversion adaptive algorithm based on LCMV and the iterative algorithm based on improved power inversion,the former one is selected to do further analysis of simulation and anti-interference performance.To improve the performance of the algorithm,this thesis analyses the effect of the space-time adaptive processing through the numbers of antenna elements,delay cell numbers and the spacing of array.Finally,in order to verify the simulation results,the experiments are carried out to test the synchronous signals received.What's more,the navigation satellite signal recording player is used to collect useful signals and interference signals.The experimental result coincide well with the simulation results.