Research On Spoofing Interference Detection Technology For Bei Dou Satellite Navigation Signals

With the development of its positioning technology,Bei Dou Satellite Navigation System(BDS)has not only played a pivotal role in the military field,but also made a significant contribution in the civilian field,and has gradually penetrated into all sectors of the national economy.However,due to the openness and fragility of its own structure,the Bei Dou signal is vulnerable to spoofing interference during its propagation.Spoofing interference achieves the purpose of spoofing by sending false signals with the same structure and different parameters as the Bei Dou signals,its purpose is to let the receiver receive the spoofing signal in an unconscious state,mistake the spoofing signals as the Bei Dou signals,and solve the wrong parameters,which leads to receiver error timing,positioning,resulting in disastrous consequences.Spoofing interference is one of the major threats to Bei Dou signals,which greatly interferes with the receiver to receive normal signals by virtue of its strong concealment,thereby affecting the positioning accuracy of BDS.Therefore,as the primary link of anti-spoofing interference,it is very necessary to study the spoofing interference detection,which lays a foundation for the subsequent spoofing interference elimination and suppression.The main contents of this paper research are as follows:Firstly,the characteristics of Bei Dou signals and the principle of spoofing interference are analyzed.Describing the characteristics of Bei Dou signal,establishing the mathematical model of Bei Dou direct spread signal.The working principle of the Bei Dou receiver was introduced,the working principle of the acquisition module and the tracking module in the Bei Dou receiver was mainly analyzed,and the receiving model of the Bei Dou direct spread signal was established.On the basis of Bei Dou signal,the principle of spoofing interference was analyzed,the mathematical model of spoofing signal was established,and the receiving model of spoofing signal was deduced,which lays the foundation for the subsequent research on spoofing interference detection technology.Secondly,study the induced spoofing detection algorithm.Aiming at induced spoofing,S Curve Bias(SCB)algorithm was studied,and the working principle of the algorithm was analyzed,the detection performance of the algorithm was evaluated by simulation,the simulation results showed that the detection performance of the algorithm is poor for induced spoofing interference with strong concealment.Aiming at the problem that SCB algorithm is not suitable for induced spoofing interference with strong concealment,proposing an induced spoofing detection algorithm based on weighted combination,which defined a new detection parameter by weighting the output value of the receiver’s prompt channel and the SCB value and selected the optimal weighting factor through simulation analysis.In order to verify the effectiveness of the proposed algorithm,different induced spoofing scenarios were set to compare and analyze the detection performance of the two algorithms.Finally,study the forwarding spoofing detection algorithm.The principle of multi-peak algorithm was analyzed,and the performance of the algorithm was evaluated by setting a variety of interference scenarios,and the experimental results showed that the algorithm is invalid for spoofing signals with forwarding delay less than 2 chip.In view of the problem that the multi-peak algorithm cannot be used to spoofing signals with the forwarding delay of less than 2 chip,the Full Width Half Maxima(FWHM)algorithm was studied and used to detect small delay spoofing signals,the effectiveness of the algorithm is verified by simulation analysis,and simulation results showed that the algorithm has poor detection performance for spoofing signals with forwarding delay less than 0.5 chip.In view of the above problem of the FWHM algorithm,the spoofing detection algorithm based on the CNR moving variance was studied,the working principle of the algorithm was described,and the performance of the algorithm was verified by setting different interference scenarios.Based on the above three algorithms,a forward spoofing joint detection algorithm was proposed,and its performance was evaluated by simulation analysis.