Research On Anti-interception Satellite Navigation Signal And Its Synchronization Algorithm Based On Phase-hopping Spread Spectrum Modulation

The Global Navigation Satellite System(GNSS)is playing an increasingly important role and is also facing various challenges.The current spread spectrum modulation scheme for satellite navigation signals is Direct Sequence Spread Spectrum(DSSS),but the development of interception technology poses a serious threat to the security of DSSS signals.The purpose of this thesis is to study new types of spread-spectrum modulation method to improve the anti-interception capability of satellite navigation signals and to improve the safety and reliability of GNSS.In order to improve the anti-interception ability of satellite navigation signals,a phase-hopping spread spectrum modulation method is proposed in the thesis,which is used as a spread spectrum modulation scheme for satellite navigation signals.The basic idea of the phase-hopping spread spectrum modulation method is to make the phase of the signal correspondingly change under the control of the phase-hopping sequence.By analyzing the autocorrelation function and power spectral density of the phase-hopping spread spectrum navigation signal,it can be known that the phase-hopping spread spectrum modulation is suitable for satellite navigation and has higher flexibility.Simulation results show that phase-hopping spread spectrum modulation method can improve the anti-interception ability of satellite navigation signals.DSSS can be regarded as a special case of phase-hopping spread spectrum modulation which hex is binary.The introduction of phase-hopping spread spectrum modulation brings new challenges to the receiving end and increases the complexity of the receiving end.In order to verify the feasibility of phase-hopping spread spectrum modulation method from the receiving end,this thesis studies the synchronization algorithm of phase-hopping spread-spectrum navigation signals.The basic idea adopted is to use complex correlation operations instead of the original real number correlation operations.This thesis analyzes the principle of signal detection and designs a fast acquisition algorithm of phase-hopping spread spectrum navigation signals.The correctness of this acquisition algorithm are verified by simulation.In this thesis,a tracking algorithm based on matching correlation is designed,and for the purpose of reducing complexity,a tracking algorithm based on carrier phase compensation is proposed.The simulation results show that both tracking algorithms can effectively track the phase-hopping spread spectrum navigation signal and have the same code tracking accuracy,but the implementation of tracking algorithms based on carrier phase compensation assistance is easier and more practical.