Study On The Influence Of Ionospheric Characteristics On Navigation Signal Reception

With the deeply development of global satellite navigation system(GNSS),GNSS has been used in all areas of national life,including agriculture,maritime,aviation,mapping and car navigation and mobile location services.One of the most important factors in determining GNSS performance is positioning accuracy.Therefore,it is necessary to continuously improve the positioning accuracy and reduce the measurement error.For many sources of error in GNSS,the ionospheric delay error is one of the main sources of error.There are two main reasons for the ionospheric delay error: on the one hand,because the ionosphere is essentially a dispersion medium,the different frequency components of the navigation signal will produce different delay when crossing the ionosphere,and for different bandwidth Of the navigation signal,the impact is also different;the other hand is due to the ionospheric irregularity caused by the ionospheric flicker.Therefore,the ionospheric dispersion and flicker on the navigation signal reception is the focus of this article analysis and research object.In this paper,the relationship between mass velocity and phase velocity,group refractive index and phase refractive index is deduced from the basic theory of ionospheric characteristics and atmospheric refraction and electromagnetic wave propagation.Then,the delay error formula of electromagnetic wave propagation in ionosphere The Then,the relationship between ionospheric delay and lattice ionospheric delay is obtained by using single layer ionospheric model and tilt factor,which lays a theoretical foundation for the study of the effect of ionospheric dispersion on broadband signal.And then introduced several commonly used ionospheric delay model,can be a good delay on the ionospheric error correction,and do not need to use the model of dual-frequency receiver measurement delay correction method.Secondly,the paper focuses on the influence of ionospheric dispersion on the reception of new broadband navigation signals.Firstly,the upper and lower sidebands of the BOC modulated signal are regarded as narrowband single frequency signals,and then the ionization of the BOC modulated signal is analyzed based on the first order refractive index model of the ionosphere.And then establish the corresponding double-sideband model.Finally,on the basis of this,we make the improvement,consider the influence of the elevation angle and other factors on the model and carry out the simulation experiment.The experimental results show that the difference between the code phase and the carrier phase of the upper and lower sideband signals is obvious.When the ionosphere is active,the code phase delay difference between the upper and lower sideband and the center frequency can reach 2 meters,and the difference of elevation angle The smaller the carrier angle difference,the larger the elevation angle,the smaller the difference,the lower the sensitivity to the ionosphere.Finally,the paper analyzes the influence of ionospheric scintillation on the reception performance of navigation signals.Firstly,the receiving model of ionospheric scintillation is established,and the fading characteristics related to flicker are introduced.Then,the receiver tracking loop error model under the influence of flicker is analyzed and analyzed according to the standard receiver tracking loop error model.Finally,The influence of the flicker on the code loop and the phase-locked loop is compared,and the relationship between the tracking error and the different parameters is compared.The correctness of the theoretical analysis is verified,which provides a reference for the design of the receiver parameters under ionospheric scintillation.