Research On Interference Mitigation Methods For Weak Signal Based On The Auxiliary Antenna

The anti-interference of weak signal is to study how to effectively suppress the influence of the interference signals for weak useful signal.With the increasing capability of the radio astronomy observation equipment,which detects the radio sources from the distant cosmic,it's also more sensitive to the man-made radio interferences which local at the same frequency range of the observation,and especially the navigation signal is particularly prominent.Thus the problem which suppresses the navigation signals in radio astronomy is typically the anti-interference of weak signal.This paper focuses on the subject background which the pulsar in L-band is often affected by the navigation signals.Based on the antenna framework which is a single radio antenna plus auxiliary antennas,the characteristics of the navigation signal are used to research the effective methods to mitigate it.The main contents are as follows: building the interference evaluation criteria,anti-interference methods by means of auxiliary antennas,antenna pattern measurement of the large size radio telescope.Firstly,according to the signal characteristics of pulsars and navigation signals to establish signal models and build evaluation criteria based on the radio data to guide anti-jamming;Secondly,the delay which is generated the spatial relative position between the radio antenna and the auxiliary antenna can't be ignored on the correlation of the navigation signal,so the variable fractional delay filter is designed to accurately compensate the signal delay;later,the feature space adaptive side-lobe cancellation method based on suppression noise is proposed,which take use of the correlation of the pseudo-code in navigation signals and the spatial characteristics of navigation satellites for the fixed orbit.The method effectively suppresses navigation signals,which is usually below the noise;Finally,In order to solve the problem which the antenna pattern of the large radio antenna is difficultly measured,the large radio antenna pattern measurement method based on correlation is proposed and can quickly and effectively measures large radio antenna pattern.The results can provide an important reference on confirming the true power of the navigation signal in the observations.