Communication Technology Research Of Space Vehicle During Blackout Range

In recent years,with the continuous development of manned space technology and the continuous application of space vehicles,the communication problem of space vehicles in the black-out area has been widely concerned by everyone.Research on the effect of plasma sheath on the propagation attenuation of electromagnetic wave produced by the spacecraft surface in the black barrier area has also become an urgent problem to be solved.Therefore,the transmission characteristics of the electromagnetic wave in the plasma sheath of the spacecraft surface in the black barrier area are studied in this paper.The main contents of this paper are:First of all,this paper analyzes the causes of the communication problems in space-vehicle black-barrier area and the generating principle and shape features of plasma sheath on spacecraft surface in black-barrier area.And research the relationship between the characteristics of each medium in plasma sheath of spacecraft.According to the data of experimental studies at home and abroad,the relevant data of plasma sheath were summarized,and the distributions of plasma electron density in plasma sheath at different heights were fitted in experimental data.Due to the double Gaussian curve of the electron density distribution of the plasma sheath in the black-barrier area above 48 km,the electron sheath density of the plasma in the black-barrier area below 48 km is Epstein curve,which is also an important parameter of the influence of the plasma sheath on the electromagnetic wave.Therefore,the black barrier is divided into two parts: the black barrier area above 48 km and the black barrier area below 48 km.The medium characteristics of the plasma sheath on the surface of spacecraft in 100km-48 km and 48km-20 km are fitted and compared.Secondly,this paper also studies the influence of plasma sheath on the attenuation of electromagnetic wave propagating on spacecraft surface above 48 km in black-out area and below 48 km in black-out area.In the course of the study,the influence of uniform plasma sheath on electromagnetic wave propagation was quantitatively analyzed and discussed.In addition to the traditional analysis,the depth of skin of the electromagnetic wave propagating in the plasma sheath was also conducted due to the conductivity of the plasma sheath similar to metal Analysis.Because of the heterogeneity of the plasma sheath,an improved gradient adaptive stratification method is proposed to stratify the plasma sheath.It is easy to use the equivalent impedance method to measure the electromagnetic wave in the plasma sheath The propagation attenuation in the sleeve is simulated.Finally,we also consider that the electromagnetic wave will also generate attenuation loss in the atmosphere during the communication between the ground station and the spacecraft.Therefore,the electromagnetic waves propagating in the commonly used frequency band above 48 km and the black-out area below 48 km have been calculated respectively At the same time,with the attenuation loss of the electromagnetic wave in the plasma sheath,the conclusion that using the high frequency electromagnetic wave can effectively overcome the influence of the plasma sheath on the electromagnetic wave propagation when the ground station and the spacecraft communicate can be obtained according to the simulation data.