Research On Jamming Detection Method For GNSS-based Train Positioning

In recent years,with the continuous development and application of satellite navigation systems in the railway field,the train positioning based on Global Navigation Satellite System(GNSS)has gradually become an important technique in novel railway train control systems.However,satellite signals are easily interfered during the propagation process under the complex external electromagnetic environment,which may lead to the performance deterioration in satellite-based positioning.With the rapid development of radio technology,the risk of signal jamming attacks with low cost devices to affect the GNSS-based positioning services is increasing,which encourage us to develop specific protection solutions against deliberate GNSS jamming attacks.The jamming protection is crucial to avoid adverse effects on operational safety of trains,railway transportation efficiency and social stability.In this thesis,the jamming detection and protection architecture is investigated for GNSS-based train positioning.A jamming detection method based on Singular Value Decomposition(SVD)and Convolutional Neural Network(CNN)is proposed.Based on that,a narrow-band interference protection method is proposed based on the Adaptive Notch Filter(ANF),which provides an effective solution for jamming mitigation in GNSS-based train positioning.The main research work completed in this thesis includes:(1)The jamming intrusion modes under GNSS-based train positioning scenarios are summarized,and the models for typical jamming signals are established.The degradation of satellite positioning performance is analyzed considering the acquisition and tracking operations in the GNSS receiver.(2)A jamming detection structure for the GNSS-based train positioning system is designed.Based on the principle of SVD and CNN,a jamming detection method within the signal domain is proposed.Based on that,a jamming detection method under the joint domain is further proposed as well.(3)A narrow-band jamming protection structure for the GNSS-based train positioning system is designed by introducing a narrow-band jamming protection strategy based on the ANF.Combining the jamming detection logic and narrow-band jamming protection logic,a complete autonomous protection solution against narrow-band jamming for GNSS-based train positioning is realized.(4)A jamming test platform for GNSS-based train positioning is built in the laboratory,and a jamming sample database was constructed.Through the jamming injection test,the proposed methods are demonstrated under typical jamming scenarios,and the jamming detection and protection capability of the autonomous protection logic against narrow-band jamming for GNSS-based train positioning is verified.This thesis considers the potential risks from the jamming interference under complex train operating environments.A complete autonomous protection scheme against the narrow-band GNSS jamming is established with the consideration of jamming detection and jamming degradation resolution.With the jamming test platform,the performance of the proposed method for jamming detection and protection is illustrated,and the whole process of the designed autonomous protection logic is simulated and demonstrated.Results of this research is with great potentials in enhancing the jamming attack protection to the GNSS-based train positioning,which will provide important assurance for the safety and reliability of the GNSS-enabled applications in specific railway systems.This thesis contains 51 figures,8 tables and 74 references.