Research On Space Target Detection Method Based On Ionospheric Disturbance Monitoring

In recent years,with the increase of human space activities and satellite navigation systems,the monitoring requirements for various characteristic parameters of the ionosphere are becoming more and more intense.The study of the ionosphere can not only promote human understanding of the near-earth space system,but also have important significance for military activities in the near-earth space.Domestic and foreign scholars have carried out a lot of research work on ionospheric detection.How to further improve the detection accuracy of ionospheric Total Electron Content(TEC)has become a key issue in ionospheric research.This thesis based on Kalman filtering algorithm,fuses the data of the International Reference Ionosphere(IRI)model with the data obtained by GPS(Global Positioning System)ground-based inversion to improve the near real-time inversion accuracy of Vertical Total Electron Content(VTEC)in the Ionosphere.Based on the interaction between space target activity and ionosphere,the GPS ground-based inversion algorithm and data fusion algorithm are used to analyze the ionospheric disturbance,so as to achieve the purpose of detecting space target activity.This thesis mainly studies from the following four aspects:1.The effects of solar activity and geomagnetic activity on the ionosphere are studied.The effects of space target activity on the ionosphere are studied.The propagation characteristics of electromagnetic waves in the plasma are analyzed by numerical simulation.The attenuation constant of electromagnetic waves is analyzed in detail with the change of the collision frequency,the frequency of the electromagnetic wave and the plasma frequency.Finally,the variation of the attenuation constant of electromagnetic wave with the collision frequency,the frequency of the electromagnetic wave and the plasma frequency is analyzed in detail.2.The ionospheric observation and inversion techniques are studied in detail.The GPS ionospheric occultation observation technology,ionospheric tomography reconstruction technology and GPS dual-frequency ground-based inversion technology are mainly introduced.The advantages and disadvantages of these observation techniques are also analyzed.The ionospheric VTEC in high latitude region,middle latitude region and low latitude region is obtained by GPS ground-based inversion.3.The existing ionospheric models are introduced,and two interpolation algorithms in the ionospheric grid model are expounded.The advantages and disadvantages of the two interpolation algorithms are analyzed through experiments.At the same time,it is proposed to use Kalman filter to fuse the data of IRI-2016 with the data obtained by GPS dual-frequency ground-based inversion,and compare the advantages and disadvantages of the fusion algorithm with GPS dual-frequency ground-based inversion algorithm in high latitude region,middle latitude region and low latitude region.It shows that data fusion can effectively improve the accuracy of ionospheric inversion.4.The GPS ground-based inversion algorithm and data fusion algorithm were respectively used to observe the ionospheric VTEC in the period before and after the launch of the north Korean launch vehicle in 2012.The GPS ground-based inversion algorithm and data fusion algorithm were used to observe the ionospheric VTEC in the period before and after the launch of the North Korean launch vehicle in 2012.The ground observation station monitors the ionospheric disturbance caused by the space target activity,thus verifying the feasibility of monitoring the space target activity based on ionospheric disturbance.