| The satellite navigation system is an important spatial information infrastructure.With the advent of GPS and the emergence of new global navigation satellite systems(GNSS),new navigation signal waveforms have been introduced.Compared to traditional GPS signals,modernized GNSS signals not only improve performance,but also ensure the compatibility and interoperability of the navigation signal in different systems.At the same time,in order to provide users with higher performance services to ensure the integrity of the navigation system,the modernized GNSS signal quality monitoring is required,if there is no timely detection of the navigation signal anomalies,it may cause great losses on the user's life and property security.The anomaly of satellite signals is one of the causes of satellite system integrity anomaly.The ICAO has proposed a classical 2OS threat model for the harmful waveform anomalies of the traditional GPS pseudo-code signal,and because of the emergence of modernized GNSS signals,it requires the expansion of the widely accepted 2OS threat model to the new GNSS signal.In this paper,the characteristics of the traditional navigation signal and modernized GNSS signal are analyzed in theory.Then,based on the classic 2OS model and the limitations of the model,the general form of the modernized navigation signal threat model is given.Finally,the general form of the threat model is applied to the BOC(15,2.5)and MBOC(6,1,1/11)signal.Mainly discussed the digital and analog threat model of MBOC(6,1,1/11)signal are studied respectively,and then theoretically analyzes the time domain waveform and the correlation function.At the same time,the error of the threat model is analyzed,and the typical range of the corresponding threat model parameters is given.The above research work can be used in modern navigation signal quality monitoring.It can quickly troubleshoot and locate the cause of the failure of the modern navigation system and signal anomalies. |
