Satellite communication timing synchronization error detection method based on full-digital receiving

Abstract

Disclosed is a satellite communication timing synchronization error detection method based on full-digital receiving. In view of wide application of a Gardner algorithm in a timing synchronization loop and the limitation of the Gardner algorithm to band-limited signals, when polarity jump happens to two adjacent symbols, after two adjacent code elements are utilized for cosine roll-off forming filtering, the relation between samples of two best sampling points and the sample of a middle point of the two best sampling points is utilized, the effect of different adjacent symbols to the middle value is firstly taken into consideration and the effect value is calculated according to the minimum mean-square error criterion, and is then eliminated; when polarity jump does not happen to the adjacent symbols, how to reduce self noise generated by the situation that timing information can not be acquired is taken into consideration. A sign function sign (.) in an E-Gardner algorithm is utilized to solve the problem. Under the satellite channel environment, the enhancing algorithm is simple in structure, under the condition of a small roll-off coefficient, the performance of QPSK modulating signal clock capturing and error detection is improved, and the satellite communication timing synchronization error detection method based on full-digital receiving can effectively eliminate self-noise and reduce system resource consumption.

Description

technical field [0001] The invention relates to space communication, in particular to the time synchronization technology of the receiving end in low-orbit satellite communication. Background technique [0002] Low-orbit satellite communication is one of the hotspots of current communication development. Due to its wide coverage, high reliability, simple network topology, convenience and flexibility, etc., it is widely used in digital video broadcasting satellite system (DVB-S) and Iridium system In the satellite communication system, the phase-shift keying (PSK) modulation method has been widely used, in order to improve the performance of the satellite modem, it is necessary to introduce synchronization technology. Symbol synchronization is one of the key technologies of the satellite communication system, and its accuracy will directly affect the performance of the whole system. With the development of computer and digital signal processing technology, the traditional di...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is: in the mobile satellite channel, aiming at the multi-value and randomness of the sent QPSK signal amplitude, even if the signal is accurately sampled, the timing error output is not zero, so it is not conducive to the synchronous loop At the same time, the system will output serious self-noise, so that the receiving end cannot accurately recover the sending signal and other problems

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