A Dynamic Delay and Doppler Simulation Method for LEO Satellite Communication

Abstract

The invention discloses a low-orbit satellite communication dynamic time delay and Doppler simulation method, which calculates the dynamic transmission time delay and dynamic Doppler frequency deviation according to the real-time communication distance between the low-orbit satellite and the ground terminal, and calculates the dynamic time-delay and dynamic Doppler frequency deviation according to the low-orbit satellite The signal transmission model designs the corresponding dynamic delay simulation system. After the sending signal of the satellite terminal passes through the dynamic time delay simulation system, the ground receiving signal under the real-time dynamic time delay scene can be simulated. In the dynamic delay simulation system of the present invention, the dynamic delay filter does not need to calculate the filter coefficients in real time, and the filter coefficients can be updated only by inputting the real time delay using the Farrow structure. Compared with other schemes, the structure is simple and the implementation complexity is low. And the simulation results are accurate. At the same time, the use of up-sampling and down-sampling processing makes the frequency band of the satellite transmission signal in the working frequency band of the time-delay filter with good amplitude-frequency response, further reducing the error of the time-delay simulation system.

Description

technical field [0001] The invention belongs to the communication field, and in particular relates to a dynamic time delay and Doppler simulation method for low-orbit satellite communication realized by using a fractional time delay filter. Background technique [0002] Low-orbit satellites operate at an orbital altitude of about 600km to 1500km, and their orbital period around the earth is less than 24 hours. Therefore, low-orbit satellites cannot remain relatively stationary with the ground receiving end like geostationary orbit satellites, but there is relative motion with the ground receiving end. The period during which the low-orbit satellite passes above the ground receiver and communicates with the ground receiver is called the overhead process of the low-orbit satellite. Due to the relative motion of the low-orbit satellite and the ground receiving end during the overhead process, the communication distance between the ground receiving end and the ground receiving ...

AI Technical Summary

Problems solved by technology

At the same time, the communication in the relative motion process will also cause Doppler frequency deviation, and the corresponding Doppler frequency deviation at different times is also constantly changing, making it difficult to accurately simulate the actual received signal of the ground terminal

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