Modelling Of BDS-3 B2 Signal Spatial Transmission Errors And Study Of Their Impact On Signal Quality

The transmission of satellite navigation signals from the transmitter to the receiver through the complex space electromagnetic environment is bound to be affected by the non-ideal characteristics of the space transmission channel,causing deterioration in signal quality and generating ranging errors.With the booming development of satellite navigation systems and the increasing reliance on them for high-quality application services,the impact of the spatial transmission error problem on the high-precision performance of satellite navigation systems cannot be ignored.Therefore,this paper addresses the characteristics of the BDS-3 B2 signal,from the narrowband interference,ionospheric dispersion effect,and ionospheric scintillation effect,to the impact of spatial transmission error on signal quality.The impact of errors on signal quality is studied in depth.The main research elements are as follows.（1）Establishing a research model on the influence of narrowband interference on the signal quality of BDS-3 B2 signalEstablishing a model for narrowband interference signals under different combinations of IF,bandwidth,and dry signal ratio,evaluating the signal quality,and collecting measured signals for verification.The results show that the larger the narrowband interference parameters are,the greater the impact on signal quality,which will cause power spectrum distortion,asymmetry in the correlation curve,correlation loss,and deterioration of signal quality,and the power spectrum deviation will be exceeded when the dry signal ratio is-15 dB,and the correlation loss will reach the critical value of the index when the dry signal ratio is-14 dB,and the overall change of SCB is small.（2）Establishing a model to study the effect of ionospheric dispersion on the signal quality of BDS-3 B2 signalThe ionospheric dispersion signal models with different ionospheric total electron number contents were established,and the signal quality was evaluated separately.The results of the study show that the signal quality is affected by the change in the total electron number content of the satellite navigation signal transmission direction.The ionospheric dispersion effect introduces a delay to the signal,transferring the energy of the real part of the signal to the imaginary part,which in turn causes the correlation curve to be delayed and the correlation curve to be faded and asymmetrical,deteriorating the signal quality,generating code phase tracking error and carrier phase tracking error,and reducing the receiver measurement accuracy.When the total number of electrons is 50TECU the signal correlation loss reaches the threshold of the indicator,causing a 44ns delay to the correlation curve,at which point the carrier phase tracking error reaches 9.5°and the rest of the term is not exceeded.However,when the total number of electrons increases to 100TECU,the ionospheric dispersion is considered to be more serious,causing a time delay of 88ns to the correlation loss,and the correlation loss is exceeded to 1.96dB,and the signal quality deteriorates sharply,while the impact on the carrier phase tracking error is greater,reaching 17.78°,which may cause the carrier tracking loop to lose lock and eventually lead to the growth of positioning error or even interruption of navigation communication.（3）Establishing a research model on the effect of ionospheric scintillation on the signal quality of BDS-3 B2 signalThe ionospheric scintillation signal models with different ionospheric amplitude scintillation indices and different ionospheric phase scintillation indices were established,and the probability distribution characteristics of the ionospheric amplitude and phase scintillation sequences were used to verify the correctness of the scintillation models,and then the signal quality was evaluated separately.The results show that the impact of different ionospheric scintillation intensities on the signal quality is large,with the signal jittering violently,energy transfer from the real part to the imaginary part of the signal,time domain waveform distortion,deviation of the main peak of the upper and lower sidebands power spectrum,deviation of the power spectrum,correlation loss,deviation of the S-curve over-zero point,deviation of the S-curve over-zero slope,carrier phase tracking error fluctuating with increasing scintillation intensity,but the S-curve over-zero slope deviation The trend of increasing curve is influenced by the influence of S₄ greater than the influence of σ_φ,the time domain waveform digital aberration standard deviation by the two flicker indices is similar,the rest of the evaluation items are influenced by the influence of σ_φ greater than the influence of S₄.