Satellite Navigation Antenna And Adaptive Anti-jamming Technology

With the improvement of the BeiDou Navigation Satellite System developed independently by China,the timing and positioning function of BeiDou System has been widely applied in many aspects of civil and military domain.Nevertheless the satellite signal is so weak when it reaches the earth that it is extremely vulnerable to the interference of the complex electromagnetic environment.Therefore,the study of adaptive anti-jamming satellite navigation antenna applied to BeiDou Navigation System is of great theoretical significance and practical value.This paper focuses on the adaptive anti-jamming navigation antenna.Some progress has been obtained on the following aspects:1.By combining the polyphase filter with the space-time adaptive filter,an adaptive filter based on sub-band processing is introduced.The sub-band space-time filter divides the signal into several sub-bands,and each sub-band is filtered independently.Due to its high computational complexity,the space-time filter is not up to the real-time requirement.The sub-band adaptive filter solves this problem by converting the high dimension operation of matrix inversion to several low dimension operations.2.A single-aperture navigation antenna is designed to meet the anti-jamming requirements of high-precision navigation and positioning.The antenna has three stacked layers of microstrips and a structure to excite orthogonal circular polarization.It covers six operating frequencies of GPS,GLONASS and BDS,realizes frequency diversity and has adaptive anti-jamming capability in polarization domain.3.A high temperature resistant array with non-welding connection which works stably for a long time under high temperature environment of 400 ? is proposed in this paper.The antenna is composed of microcrystalline ceramics and stainless steel;the patches and substrate are fixed through threaded connection of the central short pin and feeder needle;the output part is a reverse polarity joint filled with silicon dioxide.Broadband technology,the center shorting pillar and pre-attunement of the antenna are adopted to offset the influence of the temperature increment on the antenna performance.4.This paper proposes an algorithm with adaptive iteration step size based on the error power.This algorithm enhances the convergence speed,decreases the misadjustment of the LMS algorithm,smoothes the weigh variation caused by the adaptive step and avoids the spurious modulation in the iteration process.This paper proposes an anti-jamming satellite navigation antenna based on sub-band space-time adaptive filter.Through experiments,the adaptive interference cancellation capability and simultaneously suppressing of multiple interferences of the anti-jamming antenna are verified.The anti-jamming antenna processes effectively narrow-band interference to interference signal ratio of 85dB and wide-band interference to interference signal ratio of 80dB under three different j amming conditions.