Rapid frequency acquisition method, system and terminal for low-orbit satellite communication system

Abstract

The invention belongs to the technical field of space-air-ground-sea integrated information networks, and particularly discloses a low-orbit satellite communication system rapid frequency acquisition method, system and terminal. The system comprises an initial estimation and compensation module, a coarse frequency offset estimation and compensation module, a fine frequency offset estimation and compensation module and a phase estimation and compensation module. According to the method, an FCCH signal m(n) and a voice DTB burst signal r(n) which are periodically broadcasted by a satellite are received, a signal x(n) is obtained through operation, and finally demodulation, coding and decoding are carried out. By adopting the technical scheme, the communication frequency offset can be effectively reduced to the minimum range, so that the mobile terminal is simple in design at the carrier synchronization processing part, the convenience and stability of the terminal are improved, and the frequency stability in the whole satellite communication process is effectively guaranteed.

Description

technical field [0001] The invention belongs to the technical field of air-space-earth-sea integrated information network, and relates to a fast frequency acquisition method, system and terminal of a low-orbit satellite communication system. Background technique [0002] The air-space-ground-sea integrated information network is based on the ground network and expanded by the space-based network. It adopts a unified technical architecture, a unified technical system, and a unified standard specification. It is formed by the interconnection of the space-based information network, the Internet and the mobile communication network It has the characteristics of diversified service bearing, heterogeneous network interconnection, and global resource management. As an important national information infrastructure, the air-space-ground-sea integrated information network has great strategic significance for many fields such as homeland security, emergency relief, transportation, and ...

AI Technical Summary

Problems solved by technology

[0005] Data-aided estimation algorithms can be divided into frequency domain estimation algorithms and time domain estimation algorithms. Influenced by the Nyquist sampling theorem (Nyquist sampling law), at the sampling rate f s case, the estimation range is limited to [-f s / 2,f s / 2] range, or even smaller; while the frequency domain estimation algorithm mainly maps the time domain signal to the frequency domain through FFT, and uses the search peak method to estimate the frequency offset, which has a large estimation range, but because FFT cannot overcome the fence effect, so Its estimation accuracy is limited

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