Interference Mitigation In GNSS Vector Tracking Receiver Based On Array Antenna

Satellite navigation is widely used in civil and military fields.The Global Navigation Satellite Systems(GNSS)signals are vulnerable to interference,because their powers are weak on the earth's surface.For example,the signal powers of L1 frequency signals are-160 dBw.Therefore,satellite navigation receivers are vulnerable to various interference,and blanket jamming is a kind of the common jamming.It's an important guarantee for the successful application of satellite navigation to take research on anti-jamming technology effectively.Vector tracking receiver,as a new tracking technology of GNSS in recent years,combines the navigation filter with tracking loop in the Kalman filter and has advantage of tracking attenuated signal in the scene of signal interruption.Therefore,vector tracking receiver has a certain of anti-jamming ability compared with the traditional scalar tracking receiver.Up to now,the anti-jamming technology of vector tracking receiver is concerned and studied by many scholars of the world.However,traditional vector tracking loop(VTL)will lose lock when the vector tracking receiver is in the attenuation environment for a long time.In addition,the VTL is also faced with the risk of spoofing.Therefore,the combination of array signal processing and VTL can improve the anti-jamming performance of vector tracking receiver.The main contents include the following aspects:Firstly,the basic principle of vector tracking receiver is present,and intentional interference in the traditional VTL is analysed and described,which can establish theoretical basis for follow-up work.Secondly,power inversion algorithm is usually used to suppress oppressive jamming in satellite navigation system because of its simple principle.However,the satellite signals' direction and jamming signals' direction are gradually changing in the actual scene.In the case of satellite signals are near to radio frequency interference(RFI)sources,power inversion algorithm will lose lock and this will make receiver's positioning error increase.On the basis of the existing VTL based on Eigenbeamformer(EIG),this paper combines despread-respread(DR)algorithm with VTL to propose a kind of VTL based on DR,which improves anti-jamming performance of vector tracking receiver in this harsh scene.The method proposed in this paper can be applied to arbitrary array without prior information of satellites' directions and is not sensitive to the error of array.Copared to VTL based on EIG,VTL based on DR algorithm needs less correlators.Thirdly,spoofing can guide receiver to the wrong position,which is hard to be found by the user.To improve the receiver's anti-spoofing performance,spoofing detection and mitigation method based on VTL is present in this paper.This method has considerable anti-spoofing performance without knowing directions of satellites and spoofing.