Abstract: In the super solar junction (SSC) stage of deep space communications, strong solar radiation is one of the key factors that affect the calculation and analysis of the received noise temperature of the ground station. Aiming at the problem of high transmission error rate and communication interruption caused by solar radiation, taking Mars exploration as an example, a research method for calculating Sun-Earth-Probe angle ∠SEP during the operation of the orbiter was proposed. Combined with ∠SEP, the cause for the influence of the Sun on the link in the SSC stage was analyzed. The focus was on the relationship between the solar noise temperature received by the ground station and ∠SEP, air interface parameters, and antenna beam characteristics. Research and simulation experiments show that when the antenna diameter is constant, the peak value of the noise temperature received by the ground station and the influence time of the Sun on the ground station are inversely proportional to the communication frequency. And when the communication frequency is constant, the peak value of the noise temperature received by the ground station is proportional to the antenna diameter. But the influence time of the Sun on the ground station is inversely proportional to the antenna aperture. Combined with the analysis of the influence of solar radiation on the communication link, the link parameter design suggestions under different ∠SEP were given, which provided a reference for the parameter setting in the Mars exploration project.

Key words: Mars exploration, solar radiation, superior solar conjunction(SSC), system noise temperature, antenna characteristic