The Research Of The Anti-jamming Technology Of Satellite Navigation Based On Antenna Array Direction Measurement And Offset

Satellite navigation has the advantages of global,all-weather,all-day,high-precision and so on.At present,satellite navigation has become the core of modern navigation technology in the field of civil aviation and the preferred navigation source for civil aircraft.Since the navigation satellite is far from the ground,the altitude of the orbiting satellite is about 20,000 km.Moreover,the transmitting power of satellite signal is relatively low.The CA code of L1 frequency point is about 27 watts,and the power of satellite signal reaching the ground is only about-128.5d Bm,so the signal is vulnerable to suppressive jamming.In addition,the structure of the satellite navigation signal is fixed and open,which is easy to be imitated and forged and vulnerable to deception jamming.Due to the vulnerability of satellite navigation receiver to the above two kinds of interference,the interruption of navigation service and terrain warning caused by GPS signal interference in civil aviation have occurred from time to time,involving most aircraft types.Therefore,it is urgent to solve the interference problem of satellite navigation signal.In this paper,the adaptive anti-interference technology based on array antenna is taken as the research object,and the related suppressive jamming algorithm is emphatically analyzed and studied.Firstly,the antenna array is constructed according to the direction of satellite and interference signals.The simulation results show that the four-element Y-type matrix has better performance than the four-element square matrix under the condition of fewer array elements,and the quaternary Y-shaped array is selected as the array structure in this paper.Secondly,this paper studies the spatial adaptive anti-jamming algorithm for deception jamming signals,including least mean square algorithm(LMS),sampling matrix inversion algorithm(SMI)and recursive least squares algorithm(RLS),and proposed an optimization method combining LMS and SMI.Then on this basis,combined with frequency domain processing technology,studied the adaptive algorithm based on space and frequency domain,which can suppress more interference signals.Thirdly,this paper studies the spatial spectrum estimation method based on multiple signal classification algorithm(MUSIC)for deception jamming signals.MUSIC algorithm can detect the direction of arrival of satellite signals.Compared with the real constellation azimuth in navigation messages,the deception jamming signal can be detected,and then its direction can be attenuated through the antenna array.Finally,combined with the case of GPS signal interference in the field of civil aviation,the anti-interference effect of adaptive antenna technology is verified and demonstrated.The experimental results show that the anti-interference method proposed in this paper has good performance,and the adaptive antenna technology can better solve the GPS suppressive jamming or deception jamming in the civil aviation field alone.Later research can consider solving suppressive jamming and deception jamming simultaneously further.