Analysis of the Impact of Spacecraft Pointing Error on Terahertz Communication

In space terahertz communication missions, aircraft are subject to various factors such as platform disturbances and background noise, which can cause angular micro vibrations and result in non-zero antenna pointing errors, thereby affecting the overall performance of the communication system. This article combines the pointing error of typical spacecraft to establish a channel model under its influence, derives the expression of BER and channel capacity under the influence of pointing error, and quantitatively and intuitively analyzes the impact of spacecraft pointing error on terahertz frequency band communication performance from multiple perspectives such as signal constellation diagram, BER, channel capacity. The results indicate that the 16QAM modulation signal is affected by pointing errors with a RMS greater than 10 μ rad, resulting in a BER deviation greater than 4dB and a channel capacity deviation greater than 10%; At high SNR, the BER is greater than 20%, and the channel capacity deviation is close to 60%. The above results have important implications for the design of space terahertz communication systems in practice.