Research On Key Techniques Of Adaptive Interference Suppression For GPS Receiver

Global positioning system is a navigation system of timing and distance measuring space intersection,and commonly deployed to measure the speed of a moving object and estimate its three-dimension position and time.The navigation information is transmitted by radio.During the transmission,it will be subject to various types and intensity of interference.Once there is interference in the signal,the navigation receiver can not resolve the correct navigation information.Meanwhile,since satellite navigation systems have already been used widely,it is imminent to research on the anti-interference technology of this system.In this paper,I focus on the problem of adaptive interference suppression of GPS navigation receiver.It mainly uses interference signal with a certain bandwidth and a single narrowband interference as the signal model.This kind of interference is strong in intensity and influence,and often received by GPS receiver.Firstly,the paper describes the vulnerability of GPS system and the extensive application of the system,pointing out the importance of GPS receiver anti-interference.This paper analyzes the research on the estimation of interference signal parameters in the field of anti-interference at home and abroad,and on the other hand,the methods of anti-interference in time domain and frequency domain are expounded.Secondly,the GPS navigation signal model and signal characteristics are discussed,and the common interference models are analyzed.The study on frequency adaptive domain interference suppression algorithm.First of all,the paper proposes the necessity to have an accurate and determined adaptive threshold,solves the signal distortion leakage problem in the transform domain spectrum by using the GPS navigation signal windowing method,analyzes five common window functions and selects the suitable window function according to the main lobe,side lobe and side lobe attenuation speed,and in order to optimize the performance of the window function,considers the overlapping window.The algorithm has obvious optimization effect on the GPS signal interception.Secondly,the best threshold value is selected,the overall characteristics of the signal analysis system is adopted,interference detection threshold value is obtained accordingto the random signal practical distribution law,interference parameters are accurately estimated through the analysis of the interference spectrum.In this paper,the frequency domain method is used to compare the suppression effect of different interference signals,and the algorithm is simulated and validated.The study on adaptive time domain interference suppression algorithm.In this paper,I propose an adaptive time domain notch model.At first,the notch characteristics of first order complex IIR notch filter and two order direct IIR notch filter are analyzed,and the characteristics of high order IIR direct type notch filter and low order IIR direct type notch are compared.Then,two kinds of notch filters are proposed based on the design of the cascade characteristics of notch filter,respectively notch filter serial concatenation and notch filter high class association.The interference suppression simulation and the Signal to Interference plus Noise Ratio(SINR)simulation are carried out for the two cascade modes respectively,and a better algorithm of two cascade methods are obtained.In addition,the relationship between interference bandwidth,notch bandwidth and trap number of cascade from the perspective of SINR,and the appropriate number of notch filters is selected from the perspective of hardware design and resource saving.In order to form an adaptive interference suppression algorithm,the time domain IIR notch algorithm is used to suppress the interference signal,and the effectiveness of the algorithm is verified by simulation.Finally,the paper theoretically analyses that the suppression algorithm of combination of time domain and frequency domain,by detecting the interference type,it can restrain the interference and achieve better effect.With the development of space technology in recent years,many country are building or improving their own global satellite navigation system which are all based on satellite navigation and positioning system principle.Therefore,the study on the issue on interference and anti-interference on the basis of relatively mature GPS system is necessary to build and improve “Compass” navigation system of our country.